AudioCircle

Industry Circles => GR Research => Topic started by: Captainhemo on 22 Jul 2014, 05:26 am

Title: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 22 Jul 2014, 05:26 am
Not sure how interesting this will be but figured I'd post it  anyhow....

I'm starting with  one dual 12" OB H-Frame, can't afford to  do them both right now .  This will replace my current sub, a CSS Quartet 10 ( 10"  SDX 10 driver and  2 10" PR;'s).  Eventually I'll  build the 2nd H-Frame and have them config'd in stereo.

So,   I started with 4  panels,  27" x 15" x 3/4"
(http://www.audiocircle.com/image.php?id=102623)


I laminated these into 2 panels
(http://www.audiocircle.com/image.php?id=102624)

Next the panels were trimmed to size  ( 26 3/4" x 13 3/4"  and  3/4" x 1/2" dados were cut for the  baffle and braces
(http://www.audiocircle.com/image.php?id=102625)

I  cut the baffle 26 3/4" x 14" (an extra inch wider for the dados), routed the 11" holes for the woofers and  put a  small roundover on the rear  side of each cutout. Braces were cut 14" x 6 1/2".   Also  laminated  a base and a top plate that I left  long so I could  trim it off after I glued it in place
(http://www.audiocircle.com/image.php?id=102626)


Next I dry fit it all together to make sure there were no issues
(http://www.audiocircle.com/image.php?id=102627)

After that it was time for some  glue
(http://www.audiocircle.com/image.php?id=102628)

I had to use screws  instead of clamps to  glue the top plate  on,  I don't have long enough clamps  :(
Plan was to   let the glue set up and then   get the flush trim  bit out and zip off the excess....  problem.....  my  flush trim bit only has a 1"  cutting blade :duh:  Had a 2"   one sent out this afternoon.  So instead,  I   did some sanding  and  put a 3/8" round over on all the  inner edges  of the cabinet.  I'll add 3/4" roundovers to all lthe outer edges once I get the new  flush trim bit and can   cut off the excess  from the top plate.  Note, I'm  just dong the round overs on the cabinet for appearence.
(http://www.audiocircle.com/image.php?id=102629)

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 22 Jul 2014, 05:33 am
Hi Jay.
Nice project.
Nice step by step slideshow.
Anxiously awaiting the next pictures of your project.

Guy 13

Hopefully in the following threads
you will mention the following:
What finish the wood?
Spikes or rubber feet?
What make + model of plate amplifier.
What make + model of drivers?
Will the drivers be firing in opposite directions.
Will it have fron and/or back grills.
So many questions, now I can't wait for answers.

Title: Re: Dual 12" OB H-Frame Construction
Post by: mresseguie on 22 Jul 2014, 06:25 am
I agree with Guy, Jay. [Must be cuz we both have Asian wives. :lol:] That's a nice looking project you've got going.

I'm still fairly new to OB speakers, so could you educate me a bit? Where will the amplifier be placed?

Big question: What are the advantages of an OB subwoofer over a sealed subwoofer (assuming the same drivers and amps are used)?

Michael

If I should ask these questions in another thread, by all means someone redirect me. :oops:
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 22 Jul 2014, 07:18 am
 :lol:  you guys are funny.  I saw  Guy's post over in another circle  regarding  your wive's  the other day too.

No worries about asking here Micheal,,  heopefully a few others will chime in to

As I understand it,  with the OB subs, you'lll get much more detailed, accureate "clean" bass.  A lot less boom which is something I am really hoping for. With the servo controlled drivers,   you aren't supposed tolose the  "impact" either ,  just some SPL   compared to the sealed   versions.  I'm sure someone else will  provide you with more details but that's a start
  Supposed to be amazing for audio  which I have   really migrated towards since building my OB7's. I just  very rarilly  watch movies any mre  ,  pretty much all  2 (2.1) ch audio so the OB subs seemed the logical choice
Don't get me wrong ,   it is not that the OB7's don't sound good   for HT use,  I  just have lost all interest  in it. I do still wastch the occasional movie with my neice but other tan that,  nada.

Sure am looking forward to   hearing what  the OB subs  will do

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 22 Jul 2014, 07:18 am
I agree with Guy, Jay. [Must be cuz we both have Asian wives. :lol:] That's a nice looking project you've got going.

I'm still fairly new to OB speakers, so could you educate me a bit? Where will the amplifier be placed?

Big question: What are the advantages of an OB subwoofer over a sealed subwoofer (assuming the same drivers and amps are used)?

Michael

If I should ask these questions in another thread, by all means someone redirect me. :oops:

Hi Jay and Michael.
Yes, that's must be it, we both have Asian women. :lol:
I am sure some AC members will/can tell you what are the advantages
of Open Baffle versus Sealed or vented.
If I've choose Open Baffle it's not because the sealed (Servo or not)
is inferior in sound.
It's because they are different and I like something different,
plus to me, the OB sound better, at least with what I have now.
However, OB need more room, therefore later,
when I am confine into a smaller apartment,
I might (If I have no choice) go with (Several) small sealed subwoofer.
I don't want to answer for Jay, but I think the plate amplifier will be
in a separate box.
Now, I am out, I will let Jay do the writing and posting
with hopefully, lots of nice pictures.

Guy 13


 
Title: Re: Dual 12" OB H-Frame Construction
Post by: monte on 22 Jul 2014, 11:26 am
What made you do a h- frame over a w- frame? Thanks for the picts it's looking good.Keep us posted.Paul
Title: Re: Dual 12" OB H-Frame Construction
Post by: Early B. on 22 Jul 2014, 12:02 pm
Where will the amplifier be placed?

The amps for OB subs are typically in a separate box (or no box at all). One of the problems with most sealed subs is that the amp is attached directly to the box, making it subject to lots of vibration. Not a good thing.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 22 Jul 2014, 12:16 pm
The amps for OB subs are typically in a separate box (or no box at all). One of the problems with most sealed subs is that the amp is attached directly to the box, making it subject to lots of vibration. Not a good thing.

Hi Early B.
I thought that solid state amplifier were not subject to vibration.
(Tubes amplifier, yes...)
Does that means it would be better if my subwoofer ss amplifier were in a seperate box away from all the powerful boom boom of my subwoofer?
It's the first time I hear something like that.
Of course even after 66 years,
I have not heard everything about everything.

Guy 13


Title: Re: Dual 12" OB H-Frame Construction
Post by: Early B. on 22 Jul 2014, 12:40 pm
Hi Early B.
I thought that solid state amplifier were not subject to vibration.

There is an huge audiophile accessory business based on vibration reduction. Many of us who have experimented with vibration isolation devices have noticed sonic improvements, even with solid state amps. With tube amps, it's obvious to want to control vibration, but the same is true for SS amps. Imagine a SS amp's internal parts vibrating incessantly. What impact would that have on the sound (recall that sound is vibration that we hear)? This vibration issue is magnified exponentially with an amp attached to a subwoofer cabinet.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 22 Jul 2014, 01:15 pm
There is an huge audiophile accessory business based on vibration reduction. Many of us who have experimented with vibration isolation devices have noticed sonic improvements, even with solid state amps. With tube amps, it's obvious to want to control vibration, but the same is true for SS amps. Imagine a SS amp's internal parts vibrating incessantly. What impact would that have on the sound (recall that sound is vibration that we hear)? This vibration issue is magnified exponentially with an amp attached to a subwoofer cabinet.

Hi Early B.
If it's not good or even so bad,
why 99% of the speaker manufacturers attached their ss amp to the enclosures?
I wonder if I detach my ss plate amplifier from my H type subwoofer enclosure
by how much the sound will improve ???

Guy 13

Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 22 Jul 2014, 01:18 pm
Hi Jay.
Sorry to hijack your thread like that,
but while we wait for your next set of pictures,
we have nothing else better to do than... Well, what we are doing now.
If you want, you can hate me...

Guy 13
Title: Re: Dual 12" OB H-Frame Construction
Post by: Early B. on 22 Jul 2014, 01:41 pm
why 99% of the speaker manufacturers attached their ss amp to the enclosures?

That's easy -- the target market for subwoofers is comprised of 99% non-audiophiles. Only people like us would consider separating the plate amp from the cabinet. There are other reasons to do so, but we have derailed this thread long enough.
Title: Re: Dual 12" OB H-Frame Construction
Post by: corndog71 on 22 Jul 2014, 02:07 pm
Looks great so far!  :thumb:

Ever since Danny introduced the V-1 I have been wanting a pair of these OB subs.  It's amazing to me how even a fairly simple cabinet design can still be so much work.  Sadly, I am not cut out to be a wood worker. 

I would be real interested in the weight of the finished cabinet with and without subs.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 22 Jul 2014, 04:34 pm
What made you do a h- frame over a w- frame? Thanks for the picts it's looking good.Keep us posted.Paul

Figured I'd make them "match" my OB7's, an H Frame seemed  a better fit .  Usually when I see Danny  use them paired with a speaker,  they are in stand alone H Frames or built into the speakers cabnets in an H Frame.

Ever since Danny introduced the V-1 I have been wanting a pair of these OB subs.  It's amazing to me how even a fairly simple cabinet design can still be so much work.  Sadly, I am not cut out to be a wood worker. 

I would be real interested in the weight of the finished cabinet with and without subs.

I think jparkhur is working on a  simple flat pack for the H  frames,  might want to contact him and see where they  stand.
Even without  the base attached yet,  it is heavy.  With the  panels doubled up ,  the weight piles on fast.   Approx 3/4 sheet of MDF  in  this cabinet.  According to the UPS   shipment details,   the packae weights  62 lbs so  add  a good chunk of that too .

Hi Jay.
Sorry to hijack your thread like that,

Guy 13

No worries, post away   :lol:

As for the amp,  I  just built an open box  to houe it in.  I am going to put some small rubber feet on it and try it both ways... sitting ontop of the enclosure as well as on the ground to see if I notice any difference. I kind of doubt  it, but you never know

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: gregfisk on 23 Jul 2014, 03:14 am
Jay, Really nice look on these. Can't wait to here what they do for your system, I'm curious if they smooth out your room a bit and how much better the bass is.

Keep the pictures coming, I really enjoy them :thumb:
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 23 Jul 2014, 03:40 am
Jay, Really nice look on these. Can't wait to here what they do for your system, I'm curious if they smooth out your room a bit and how much better the bass is.

Keep the pictures coming, I really enjoy them :thumb:

Hey Greg,  any word on your   project   ?    Been anxiously awaiting to see how they are going to   look  :)

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: monte on 23 Jul 2014, 06:34 am
This is what I want to replace my sunfire jr with.
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 24 Jul 2014, 11:12 pm
Really excellent H-Frames, Cap. They look to have been inspired by the black pair Peter J made and posted pics of here awhile back (the top and bottom of the frame extending past the vertical side panels). I'm using W-Frames at the moment, but when I get around to making H's, I'm making mine in a similar design (but without the extended top and bottom), also doubling up on the MDF for the panels, and the baffle as well, just to make sure. Doubling the horizontal brace seems unnecessary, I think. What do you say Danny?
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 24 Jul 2014, 11:21 pm
No need to double up the horizontal brace.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 24 Jul 2014, 11:57 pm
Really excellent H-Frames, Cap. They look to have been inspired by the black pair Peter J made and posted pics of here awhile back (the top and bottom of the frame extending past the vertical side panels). I'm using W-Frames at the moment, but when I get around to making H's, I'm making mine in a similar design (but without the extended top and bottom), also doubling up on the MDF for the panels, and the baffle as well, just to make sure. Doubling the horizontal brace seems unnecessary, I think. What do you say Danny?

Once  the  new flush trim bit arives (need a longer one), that top panel will be trimmed down to the overall width .I did see the pics  you mention, I think they were actually made by Ruben  (post #59 http://www.audiocircle.com/index.php?topic=125667.40 ) and  really liked them, thought about going the same way but I want these towers to have a similar shape to the OB7's (at least from the front) so there will only be the wider base.   I did not double up the baffle or the braces.... thought about  doing the baffle  but figured with the dados and the little area of baffle left exposed,  there would be little room for any   movement /resonance once the drivers are installed.  It's  very solid as it it is

Not much I can do  until that bit arrives .... this afternoon I did  finsih up the open box for the amp Gone back to the Duplicolor paint for the finish but going a little draker than the  OB7's ,  figured the darker color  would   be more versitile if I ever decide to change spekaers in the future . Color is  called  Metallic Graphite.

(http://www.audiocircle.com/image.php?id=102743)


-jay .
Title: Re: Dual 12" OB H-Frame Construction
Post by: gregfisk on 25 Jul 2014, 01:49 am
Hey Greg,  any word on your   project   ?    Been anxiously awaiting to see how they are going to   look  :)

-jay

Derailing your own thread huh :lol:

All parts are apparently cut out and paint should be happening now? I can't wait either, I'm really looking forward to getting them home so I can put them together.

I will keep you posted, thanks for asking.

Greg
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 25 Jul 2014, 10:19 am
You're right Captain, they were Rubens. Damn memory! You're probably right about the baffle as well. With so little baffle area left once the woofers are mounted, not much left to resonate. Once again, I ask for Danny's input.

Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 25 Jul 2014, 01:07 pm
You're right Captain, they were Rubens. Damn memory! You're probably right about the baffle as well. With so little baffle area left once the woofers are mounted, not much left to resonate. Once again, I ask for Danny's input.

I thought I answered your question in post number 18. Did I miss a question?
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 25 Jul 2014, 04:29 pm
You answered the question of not needing to double the horizontal brace. This one concerns whether or not the baffle would benefit from being doubled. Thanks Danny.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 25 Jul 2014, 05:10 pm
You answered the question of not needing to double the horizontal brace. This one concerns whether or not the baffle would benefit from being doubled. Thanks Danny.

You could if you wanted to, but I don't see a benefit. There isn't much there but a frame when you cut the mounting hole out of it.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 25 Jul 2014, 05:14 pm
With an H frame like the Super-V, the frame is just big enough for the woofer (13" square) and then there is a four sided box mounted to it.  So it is very solid.

(http://gr-research.com/mis/superv1.jpg)

Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 26 Jul 2014, 07:23 pm
Good enough for me. Plus, Jon's new H-Frame flat pack is made with a 3/4" baffle. I know you prefer MDF to Baltic Birch in general Danny. Any reason to go with BB in an H-Frame?.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 26 Jul 2014, 07:50 pm
Good enough for me. Plus, Jon's new H-Frame flat pack is made with a 3/4" baffle. I know you prefer MDF to Baltic Birch in general Danny. Any reason to go with BB in an H-Frame?.

The BB will be fine for the H frame application. I like them about the same in this application. The side panels are not excited as to resonate. They are more prone to flexing under the pressure they see. So the BB works fine.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 1 Aug 2014, 03:48 am
Ok, here's some more progress fianlly...  took   a week and a half to get the router bit I needed.
Note, pay attention to what you are ordering...  the bit arrived and it was only 1/4" shank with a 2" cutting blade !!   I can't believe they even  make such a thing  but serves me right for not paying attention . Anyway,   needless to say,  I had to trim the top  panel very slowly and  couldn't put too much  presuare on that bit,  was really worried  I was going to bend/sanp    the bit.
(http://www.audiocircle.com/image.php?id=103137)

But I did get it  done with some patience
(http://www.audiocircle.com/image.php?id=103138)

Next I removed the temporarily installed base after  marking it with  a couple reference points for lining it back up  once  I   was ready to permanently   attach it..  I then  rounded ove the corners with a 3/4" round over bit and also did the  upper edge
(http://www.audiocircle.com/image.php?id=103139)

Next   I took the 3/4" round over bit to the outer edges and also to tpe   top panel of the cabinet
(http://www.audiocircle.com/image.php?id=103140)

After giving it all a thorough sanding I reaattached the base   this time using  a nice layer of glue.  I had thought about making the  base removable but  really didn't see a need for it... permanent it is.
There is one little knick in the upper  right corner (verwed from front) that I must have    done with the router,  will have to     touch it up tomorrow. 
(http://www.audiocircle.com/image.php?id=103141)

Slipped  out to HD this eve and picked up a piece of  1/2 MDF   so I'll   whip up a grill frame tomorrow afternoon and maybe get  the magnets set in place.  Not sure  I'll even use a grill  but better to  have it and not use it  rather than  want it and not have it   :lol:

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: ZAKski288 on 1 Aug 2014, 04:31 am
Nice Job :thumb:  Someday I hope to make a pair myself.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 2 Aug 2014, 04:39 am
Nice Job :thumb:  Someday I hope to make a pair myself.

Thanks man.  I'd have liked to have done a pair at the same time but  couldn't swing  the funds so doing   1 H Frame at a time.  Hopefully it woun't be tooo long before I can do the 2nd  .

Ok,  grill frame....

1st I cut the piece of  1/2" MDF to  the size I wanted for the grill.  Sized it so it would sit  1/2"  insded the cabinet outer edges on the sides and top, it will site down  on the  base at the bottom.  Once I had that cut,  I  marked out the 6 locations for  the magnets and then used a 1/8" drill bit to  drill  right through each spot.  With my  low vision, I find doing it this way  is much easier  than rasfering the measurments to the cabinet, plus I can use the  through holes  later.  Once I'm done and the  magnets are epoxied in, I can  just    fill the little holes with  either a little glue or wood filler.
Once the holes are all drilled I clamp the  grill blank in place on the cabinet, spacing it equally  on both sides then  use the same 1/8" drill bit to  mark the  cabinet at each spot.
(http://www.audiocircle.com/image.php?id=103196)

After each hole is  marked on the cabinet,  I remove the grill blank and proceed to drill the  holes for the magnets.  In this case I had planned on  using  1/4 x 1/4 N52 cylinder magnets (thought I had some)  but  after looking closer at what I had on hand,  I found I only had  3/16 x 1/4 N52's which are going to have to do.  I'm sure using 12 ( 6 in cabinet, 6 in grill frame) will work fine, these little guy are  surprisingly  strong.

After drilling the holes in the cabinet, I  epoxy the mangents in place.  I usually  smear a little wood filler over each one just to fill in the "edge"  around each magnet.   Run a  piece of 120 grit over each one  using a block after  it drives. 
(http://www.audiocircle.com/image.php?id=103197)

Now it is on to the  frame itself.   I decided to   leave the frame 1" wide on the edges.   It's 15" wide  so a 13"  cut out should work great...   I left the bottom frame 1.5"  thick for  something later.  Befroe routing out the holes,  Ir ounded each corner  and then ran a 3/8" round over  around the outside.  Then  I  routed out the  large  holes
(http://www.audiocircle.com/image.php?id=103198)

After this, it's just a matter of  getting rid of the little  pieces left over in the middle. Time to put those little 1/8" holes  I drilled all the way through to use again.   I use them to run a  #6 x 1"  wood screw through and attach a  guide for  a flush trim bit to cut out the little excess pieces.  This works well as long as you aren't distracted  and thinking about  other things  :duh:  Note the little  blooper in the lower left corner,  don't ask what I was dong  cuz I can't  tell you.  At least it is only a grill frame  and  some MDF  saw dust mixed with some glue easily filled it in.   
(http://www.audiocircle.com/image.php?id=103199)

I wanted to finish this up this eve but  I'm going to let that patch  cure overnigh before I run a 2/8" rond over around the inner edge of the frame

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 2 Aug 2014, 07:17 am
I really like the proportions of your H-Frame. They're about the same as those of the flat pack Jon is now offering, except that yours has a doubled thickness MDF top. I've been envisioning an H-Frame along the same lines, but for anyone thinking of also making their own frame (though Jon's flat pack makes that unnecessary) with this difference: Instead of attaching the grill frame to the front edge of the double-thickness top and side panels, I was going to make the outer 3/4" panel of the top, bottom, and sides extend past the inner 3/4" panels by 1". Then a grill frame could be made slightly smaller than the inner dimensions between the top & bottom and two sides, and inserted into the front cavity, making it (with the thickness of the grill cloth, and Velcro to hold the grill in place) about flush with the outer panels, like speakers from the 60's and into the 70's (picture the AR-3). Just an idea.
Title: Re: Dual 12" OB H-Frame Construction
Post by: monte on 2 Aug 2014, 10:50 am
Jay your grill is exactly what I was thinking about. Have you decided on a color or veneer.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 2 Aug 2014, 03:53 pm
bdp24

Yeah, the dimensions I used are pretty much the same as the  Super V H frame....Side panels are 3/4" taller as I didn't stagger the  braces , just ran the dado straight  across and also the extra 3/4" from the  douoble layer top panel
Leaving the  ouoter panels a bit  wider to create a recess for the grill would work and probably look prety cool  :thumb:  I'd prefer the magnets over the velcro as they are never seen... just remember to make a little tab or something to remove the grill,  those little magnets are strong and with  the  frame inside a  recess,  it may prove awkward to remove  without something to  grasp.  You  could also do as Jon suggested over in his flatpack thread ...  make the cabinet as is  and make a full sized grill .  Just omit the round over on the  outer edges of the H frame and make the grill frame pretty much flush .  I did exactly that  onthe  XSL Encores for my neice and I like   how the look.

monte ,
I wanted the grill frames "match"  my  OB7's.  The H frame will  be painted in the same Dupli Color  Metallic paint I used for the OB7's but  the next darker  color , which is called  Metallic Graphite .   Back on page  1,  there is a picture of the amp box painted in it. Figured by going  darker,  the subs  would pretty much go with anything if I shold ever decide to   change speakers.... not  likely for some time though  . The 7's are  in Metallic Charcoal but you can see the  "look" should be similar
(http://www.audiocircle.com/image.php?id=77757)

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 2 Aug 2014, 04:52 pm
Looking really good there Jay.

Mike
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 2 Aug 2014, 10:43 pm
Fixed up  that little  mistake  from yesterday   and  put a 3/8" round over on the inside edge of the  grill frame this morning
(http://www.audiocircle.com/image.php?id=103223)


Epoxied in al lthe  magnets
(http://www.audiocircle.com/image.php?id=103224)


Gave the whole thing a light sanding  and poped it on the  H frame.  Amazing little magnets,  that thing snaps into place.   As with any of the magnets I've used, once it's in place,  yo can shift it slightly  from side to side  for fine adjustment if yo are  a detail freak
(http://www.audiocircle.com/image.php?id=103225)

Now just need to  roll a coat of paint  over it and  wrap in grill cloth :beer:

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: cody69 on 2 Aug 2014, 11:35 pm
Quote
Now just need to  roll a coat of paint  over it and  wrap in grill cloth

Jay - Am following your build with great interest. If you wouldn't mind, appreciate if you'd post a few pics showing how you wrap and fasten the cloth to the grill frames. My woodworking skills are pretty fair, but my grills are nothing to write home about. The outside looks fine, but when pulled off, the inside looks somewhat amateurish. The corners throw me off, pleats... gathering... folding... have not found a technique that doesn't bunch up the fabric when I turn a corner.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 3 Aug 2014, 12:08 am
Jay - Am following your build with great interest. If you wouldn't mind, appreciate if you'd post a few pics showing how you wrap and fasten the cloth to the grill frames. My woodworking skills are pretty fair, but my grills are nothing to write home about. The outside looks fine, but when pulled off, the inside looks somewhat amateurish. The corners throw me off, pleats... gathering... folding... have not found a technique that doesn't bunch up the fabric when I turn a corner.

Afraid I'm  in the same boat man.  Mine always look good fromthe front, but I always tell people  just don't turn them over and look at theback  :lol:   Honestly, I'm embarrassed by the back of them
Not really sure what the answer is maybe someone  who is good at upholstery can give us  some pointers  .
I know some guys use the  spray adhesive instead of staples,  was thinking of trying that  but I just don't see it being sstrong enough and it  doesn't help the issues with the corners.  If  I can do any better with the back of this,  I might actually show  the back but no promises  !!

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 3 Aug 2014, 12:17 am
Afraid I'm  in the same boat man.  Mine always look good fromthe front, but I always tell people  just don't turn them over and look at theback  :lol:   Honestly, I'm embarrassed by the back of them
Not really sure what the answer is maybe someone  who is good at upholstery can give us  some pointers  .
I know some guys use the  spray adhesive instead of staples,  was thinking of trying that  but I just don't see it being sstrong enough and it  doesn't help the issues with the corners.  If  I can do any better with the back of this,  I might actually show  the back but no promises  !!

-jay

Hi Jay.
I saw my cabinet maker installing the grill cloth on my V1
and on the back he uses some liquid adhesive
and with a cloth iron with just a little heat even out all the wrinkles.
It does a nice job.

Guy 13
Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 3 Aug 2014, 12:52 am
Gave the whole thing a light sanding  and poped it on the  H frame.  Amazing little magnets,  that thing snaps into place.   As with any of the magnets I've used, once it's in place,  yo can shift it slightly  from side to side  for fine adjustment if yo are  a detail freak
(http://www.audiocircle.com/image.php?id=103225)
-jay

Jay,

I was thinking along the lines of Ed's suggestion about insetting the grill but that really looks good.

Mike
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 3 Aug 2014, 02:06 am
Captain---The reason I was thinking of Velcro is because the magnets are so attracted to each other that getting the grills back off after they are inset into the H-Frame might be a problem. Velcro holds, but without the strong magnetic pull. I would never be using H-Frames without grills, so the look of Velcro wouldn't be an issue. Speaking of grills, I watched a friend of mine while he put new vintage reproduction grill cloth on my '67 Fender speaker cabinet; he stapled the cloth onto the back of one of the short ends of the grill frame and then stretched the cloth as tightly across the length of the grill as possible, stapling the other end of the cloth to the back of the other end. Then he did the same across the width. He told me the longer the length of cloth, the more it stretches (makes sense), so length first is the way to do it. With a pair of scissors he cut into the corner at a 45 degree angle, then cut off the extra material (to get rid of the bulk), and folded and stapled the cloth onto the frame. The stapler he used was pneumatic, with staples having a depth of about 1/2". The cloth now sags just a little in the middle, but it is much thicker and less stretchy than the cloth anyone here would use, and was very difficult to pull even as tightly as it was. I would pull the cloth as tightly as possible without ripping it---the 3/4" MDF grill frame won't bend from the pull of the cloth.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 3 Aug 2014, 04:38 am
Jay,

I was thinking along the lines of Ed's suggestion about insetting the grill but that really looks good.

Mike

Thanks Mike  hoping there will be enough metallic in this paint to get some of the same contrast  that I get with the  OB7 grills when the light hits the paint.  I actually considered going with the same color  on the subs , was a bit torn between  the  contrast  and the versitality of going darker (goes with  anything) .  The decision was made for me when I found out  that this paint is no longer  available in Canada but I did mange toi find a few cans of the  metallic graphite so boought them.   I could have ordered the same charcoal I used previously but   Jegs wanted  close to $20 / can  for the shipping alone !

bdp24,
I hear you  on the magnets, wondered if that might be an issue with a recessed grill. I even wonder if the velcro would cause problems...if the grill is actually flush or below the surface of the outer panel, it could prove   really hard to   remove.  Don't really see how you'd grab it
Thanks for the  clothng ideas.  I've never had any issue withe geting the cloth nice and tight ( thin stuff)  just those dam corners are  messy .   Was thinking of  45'n  the excess in the corners already, may have to give it a try.  There are some tutorials   ouot there too

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 3 Aug 2014, 10:41 am
     Some of the speakers in the 60's and earlier with inset grills actually had nothing holding them in place except the friction of the frame and cloth against the inside edges of the cabinet. When I got my first pair of real hi-fi speakers (AR 4ax's) I wanted to look at the drivers, and I just (carefully!) put a butter knife into the space between the grill and the cabinet and pried the grill off. No harm done, but I was kind of surprised by how crappy the drivers and baffle looked. No one would want to listen to speakers with the grills removed back then if it meant having to see the hideous looking baffle (glue smears, ugly particle board, not MDF), woofers and (especially) tweeters. The irony is, grill cloth back then was so thick (like burlap!) and acoustically non-transparent that the speakers would have sounded better without the grill cloth between the drivers and our ears. The frequency response was tailored to compensate for the cloth, but still.
     For these H-Frames, I won't be removing the grills after they are put in place anyway, so I'm not concerned about the appearance of the Velcro. Grills mounted to the front of the frames, such as yours, are unquestionably much easier to add without having to modify the frames. I just really like the old school look of AR, KLH, Dynaco, Advent, Klipsch (they are STILL made with inset grills), etc., speakers, with the grills flush with the front edges of the cabinet. For those getting Jon's H-Frames, the inner side panels and horizontal brace can be cut back an inch, and grill frames made to fit in the recess, for those who also like the old look. Either way, these are fantastic subs, aren't they?!
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 7 Aug 2014, 12:44 am
Here's the grill frame with a coat of paint, just some Satin Black Behr Premium Primer/Paint
(http://www.audiocircle.com/image.php?id=103495)
I went to the local store that usually carries the cloth,  found out they are moving and have cleared  everything out and aren't bringing any more in until after the move.  I had to order a yard from  Vancouver, hopeuflly it will show up by   Fridday

Cabinet  all primed up with Bulls Eye 123. primer/sealer , this stuff seems to adhere extemely well to the MDF
(http://www.audiocircle.com/image.php?id=103499)

(http://www.audiocircle.com/image.php?id=103497)

I picked up a bag of these M8 x 13mm threaded inserts , going to give them a try instead of the inserts that come  with the spikes
(http://www.audiocircle.com/image.php?id=103498)

Gong to  get the  top coat on in the next day or so. 

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: PDR on 7 Aug 2014, 05:11 am
Great job, looks like its going to turn out VERY nice!..... :thumb:
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 8 Aug 2014, 04:29 am
Great job, looks like its going to turn out VERY nice!..... :thumb:

Thanks Perry :)
After I last  "talked" to you, I did a bit more research on the Poly Diffusers and found a thread  in the GIK circle where Bryan recommended  a diffuser behind each   OB speaker. Decided to give this a try and it is working well.  Planning to eventually replace  with a couple of the PI Audio diffusers  but for now these are staying put

Anyway , sprayed the top coat on this afternoon.   Here is a shot of the  Metallic Graphite trying to show  how much it changes   in the light,  had to sue the flas as it was already  sundown when I took these
(http://www.audiocircle.com/image.php?id=103534)

And here are a couple of the cabinet itself
(http://www.audiocircle.com/image.php?id=103535)

(http://www.audiocircle.com/image.php?id=103536)

I'm pleased with the resuults, I''ll  grab a coule shots tomorrow afternoon when the sun  is poking through the back door of the garage.
Now I  just need that grill cloth  and more importantaly,  a delivery from  my buddy who has the packages from Danny  ,.. right Holmes  ?   :lol:

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: monte on 8 Aug 2014, 10:45 am
Jay, looking good. Those early Christmas presents are fun to open. Keep up the good work .
Paul
Title: Re: Dual 12" OB H-Frame Construction
Post by: Mr. Oczka on 8 Aug 2014, 02:26 pm
Damn, those look fine!!!  Just curious, how did you apply the sealer?  What brand paint did you use for the metallic Graphite?

thanks,

tom
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 8 Aug 2014, 03:53 pm
Jay, looking good. Those early Christmas presents are fun to open. Keep up the good work .
Paul
Paul,
Yes they are  !   Looking forward to it

Tom,
I found a can of the BullsEye 123 primer/sealer in a spray bomb so I used that.. however, the 1 can I picked up was not enough so I  went back and  decided to get a  liter can which  was about 3 times the quantity of paint for the same price.  I rolled  it on and  just gave it a light sanding with a block .
The paint is made by Dupli Color

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: ebag4 on 8 Aug 2014, 11:58 pm
That sub turned out great Jay, nice job.  I will likely be spraying my next project with rattle cans, I pickup up some Duplicolor metalcast to practice with, painting has never been my strong suit but I am encouraged by your excellent results.

Best,
Ed
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 9 Aug 2014, 03:22 am
Hi Jay.
May I say that the color of your enclosure is not my favorite color.
(I prefer lighter color, but that's your choice and I really respect that.)
That's being said, I love your wood work and the paint job.
I wish my subwoofers would look as nice as yours.
I think with front grill it will makes a better looking enclosure,
that's what mine are missing.
I am riveted to my computer's screen to see and enjoy the end result.

Guy 13
 
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 9 Aug 2014, 04:42 am
That sub turned out great Jay, nice job.  I will likely be spraying my next project with rattle cans, I pickup up some Duplicolor metalcast to practice with, painting has never been my strong suit but I am encouraged by your excellent results.

Best,
Ed

Hey Ed, thanks for the comments.  if I can give you one tip for painting,  it would be prep, do lots of block sanding and get  everything as good as  you can   With every project,  I do more prep  and  end up with better results.  Learning my lesson :)
 Not sure if anyone else is using it , but I was  really impressed with how well that Bulls Eye 123  primer/sealer aheared to the MDf and  it covered very well too.   I let it dry overnight  and then give it a quick sanding  with a block  and some  240 , then a final   pass with 400. 

Guy,  no worries,  everyone has different  tastes in color.  As I mentioned  earlier in the thread,  I  almost went to the same color as the OB7's which is a shade lighter, almost silver in the light.    Unfortunately,  I can't get that paint in Canada anymore  but did manage to find some of the graphite so that really helped make the decision .  This stuff will   stand out pretty well  in the natural light I think

As for the grill, well , here you go
(http://www.audiocircle.com/image.php?id=103584)

I'll post a bit more about the fiasco with the grill cloth tomorrow,  need to jump inthe shower and   have a Corona after, maybe even a couple, time to relax  :beer:

Oh,   figured I'd share this too as I know there are a few dog lovers out there....  Roxy likes to hang out inthe garage and  watch the projects  progress, crazy dog even stays in there when I'm  running the table saw  or router   !!
(http://www.audiocircle.com/image.php?id=103585)
 
-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: gregfisk on 9 Aug 2014, 06:24 am
Jay, those look great! I like the grills, gives them a nice finished look especially with the softened inside corners.

I think Roxy is just keeping a watchful I on you, you know in case you make mistake and need to be saved :o
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 9 Aug 2014, 06:30 am
Hi Jay.
I really like how your grill look like.
I would like to do the same with my enclosures,
but unfortunately, it's too late now.
I have to tell you a little secret,
I've hired your pouch to spy for me on how to do wood work.
He will report to me, when he know how to use the computer.
Next step, the woofers ?

Guy 13
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 9 Aug 2014, 10:03 am
Handsome cabinet AND dog! The grill looks as good as the cab, and keeps listeners from thinking about the sub's "guts" too much. Now, after you install the woofers, let us know what you think of the sound, the ultimate point of all the work.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Ron on 10 Aug 2014, 03:06 am
  Excellent job Jay. Your OB H-frame cabinet looks great!  :thumb:  I'm anxious to hear your report on how it sounds
once you get the components installed and have a chance to test it.

Ron
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Aug 2014, 03:47 pm
Thanks for the comments you guys, really looking forward  to getting it up and running.

Funny about the dog Greg,  she definitely likes to keep an "I" on things and now I know why  Guy !! Guess we'll know why a couple boxes of Milk Bones arive from planet Viet nam huh  ?  :lol:

Cody698,  I found this  which may interest you, 
https://www.youtube.com/watch?v=BQ1H3_uv2uE

I tried to  do the same basic  thing as the video shows but am still too ashamed to show the  rear  ,  not pretty.  My biggest mistake was not  using quie a wide enough piece of cloth,  had I made it an inch or two wider to start with,   it would have been much better, I ened up having to really stretch the sides over to  just get a staple in .  Lesson learned for the next one. 
With the much more flexible grill cloth we typically use,  you still can end up  with a bit of a problem in the corners but  I  just used a little  bit of  adhesie on a q tip   right at the corner on the rear which helped a lot

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: monte on 10 Aug 2014, 04:03 pm
Jay, do the speakers and amp come in kit form or do you buy them separately.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Aug 2014, 04:23 pm
Jay, do the speakers and amp come in kit form or do you buy them separately.

Seperately, but, just give Danny a call and he will set you up with all the components you need.  remember too,  if you are only doing  dual  driver OB  (H, W, U frmes), not triples,  he has the new 8 ohm  drivers coming in shortly

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: monte on 10 Aug 2014, 04:47 pm
I believe I read that the 8 ohm 12's would be in around the end of Aug.
Title: Re: Dual 12" OB H-Frame Construction
Post by: cody69 on 10 Aug 2014, 05:09 pm
Quote
Cody698,  I found this  which may interest you, 
https://www.youtube.com/watch?v=BQ1H3_uv2uE

Thanks for posting this. The video is interesting and the miter corners look like a good approach when the sides of the grills meet at a rectangular corner.
Did you use this method with the slightly rounded corners you have on the H-Frame?
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Aug 2014, 05:46 pm
Thanks for posting this. The video is interesting and the miter corners look like a good approach when the sides of the grills meet at a rectangular corner.
Did you use this method with the slightly rounded corners you have on the H-Frame?

Yes I did, or at least I tried  ....  .  As mentioned,  I really  didn't   cut the original piece wide enough, if it had been   a couple inches wider it wold have  looked much better as I could have  trimmed up the   rear so much  nicer. 
With the rounded corners,  you do still get a lttle  bunching, but if you really pull it and use just a dab of adhesive on the back right at the corner,  it works quite well.

This is embarragsing, but  :wtf:    I have no clue as to why I struggle so much doing these....
(http://www.audiocircle.com/image.php?id=103661)

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: monte on 10 Aug 2014, 07:27 pm
If somebody asks to see the back of your grill,throw them out. Good job
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 10 Aug 2014, 11:21 pm
Hi Jay.
If you don't like the way the back of your grills look like,
I can relieve you of the shame you might suffer when your friends
will see the back,
by taking them away from you. :lol:
Nice job, if I was you I would be proud, look nice from the front.  :thumb:
I don't even have myself any grills, even after two years of the original built.
Next step, the drivers ?

Guy 13
Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 10 Aug 2014, 11:38 pm
Yes I did, or at least I tried  ....  .  As mentioned,  I really  didn't   cut the original piece wide enough, if it had been   a couple inches wider it wold have  looked much better as I could have  trimmed up the   rear so much  nicer. 
With the rounded corners,  you do still get a lttle  bunching, but if you really pull it and use just a dab of adhesive on the back right at the corner,  it works quite well.

This is embarragsing, but  :wtf:    I have no clue as to why I struggle so much doing these....
(http://www.audiocircle.com/image.php?id=103661)

-jay

Jay,

As long as it works what does it really matter? After all, you don't see the back side of the grill frame.

Mike
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Aug 2014, 11:56 pm
yup, I hear what  you guys are saying and you are right, it looks good from the ront and  it will finction as  planned.  I guess it is more about improving each time I build one of these and while the wrapping did go better,  it  did not  come out as I had hoped, in that way it is disappointing. 
When I look back at  what I did with the N3 grills, (my fist grills)   the improvement is dramatic, I really need to redo those for my folks but again, they also look fine from the front.

Guy, depending on how your  cabinets are  finished,   it may not be overly difficult to do  frames for  them.    If they are veneered,  you can always get those  push in/on type  fastners , if painted you could use a similar  technique  that I used and  clamp the  frame in  place before drilling small through holes to mark the locations of the magnets.  Once the magnets are in place, it would be a matter of  touching up  the paint and  a little cut polishing 

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 11 Aug 2014, 03:34 am
yup, I hear what  you guys are saying and you are right, it looks good from the ront and  it will finction as  planned.  I guess it is more about improving each time I build one of these and while the wrapping did go better,  it  did not  come out as I had hoped, in that way it is disappointing. 
When I look back at  what I did with the N3 grills, (my fist grills)   the improvement is dramatic, I really need to redo those for my folks but again, they also look fine from the front.

Guy, depending on how your  cabinets are  finished,   it may not be overly difficult to do  frames for  them.    If they are veneered,  you can always get those  push in/on type  fastners , if painted you could use a similar  technique  that I used and  clamp the  frame in  place before drilling small through holes to mark the locations of the magnets.  Once the magnets are in place, it would be a matter of  touching up  the paint and  a little cut polishing 

-jay

Hi Jay.
When it comes to woodworking or DIY projects,
I am a BIG ZERO.
I don't have four fingers and one thumb, I have five thumbs per hand.
The Vietnamese cabinet maker uses those little push in the hole devices
and they never hold in place the grills,
what I did to solve that annoying problem is to add lots of Velcro strips around the grills,
it holds everything in place, but it also create a gap,
but looking at the grill from the front, it does not show, same as yours.
So, no problem, I'm happy.
As for the grills on my V2 Ferrari red speakers,
I have the cloth, I have the Velcro, I am only missing the 1/4" MDF or plywood, which is inexpensive
on this planet.
The only other thing missing I the courage or the get and go to start the project.
Like I say before and I am repeating myself (Normal I am an old fart) next step, the woofers.

Guy 13
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 11 Aug 2014, 03:58 am
Sorry man, yup, next step is the woofers,    just been  a slight delay in getthing them ( nothing to do with Danny btw) but  soon enough, soon enough   :)

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 27 Aug 2014, 08:54 pm
Got my parts  from my buddy at the coast about a week ago so I've put a bit of time  on the subs and am  loving them  :drums:

First, here a few pics
After installing the drivers,  I cut  all the no rez, 8 pieces 6.25" x 13" and 8 pieces 6.25" x 11".  I then cut  a 1.25 strip  of the foam (leaving the dampening layer)  off each piece to leave  clearence front and back.
(http://www.audiocircle.com/image.php?id=104492)

Here is the rear after the no rez. The  upper side pieces of no rez  were  just slid into place  until  the wires were actually sodered. I used the  quick clips on the driver to make sure I had all the wiring correct before sodlering.
(http://www.audiocircle.com/image.php?id=104493)

Front view after it's all soldered up.  We went and forgot the  shrinktube  :duh:
(http://www.audiocircle.com/image.php?id=104494)

Used a handy 4-pole quick connect for the  wiing to the amp  which I got from Danny with the  rest of the parts
(http://www.audiocircle.com/image.php?id=104498)

Grill  with the GR logo of course 
(http://www.audiocircle.com/image.php?id=104495)

(http://www.audiocircle.com/image.php?id=104496)

(http://www.audiocircle.com/image.php?id=104497)


The H Frame has  blended so seamlessly with my OB7's it's amazing.  It actually seems like  I have no subs,  but all the suden  the OB7's reach way down deep.  I was telling Ron that the bas from the H Frame  is very similar to the mid bass produced by the 4  M130X drivers in each  OB7.  It is so clean and well defined, the detail is wonderful, brings a whole new "layer"  to the music that I didn't even know I was missing.  Plus, at moderate and lower listening levels,  pretty much all the boom is gone from ny room ,  it starts to creep back in a bit when  I start rolling over the volume dial but  I'd imagine that is mostly due to the lack of   treatment in my room.

My previous sub was based on the  SDX 10 driver  which is a push/pull  (XBL2 motor)  driver and I always thought it sounded pretty good. It actually does sound prety good compared to some other subs I have heard but  it's not in the same league by any means as  this design. 

Truely impressive Danny  :thumb:
-jay

Oh, if I am not using the  RCA outs, should I have the  amp's low pass slope set to  EXT/12 or does it matter ?  .  Funny, with some  music  I prefer the EXT/12 setting, with other  music I prefer tje 80/24
Title: Re: Dual 12" OB H-Frame Construction
Post by: monte on 27 Aug 2014, 09:12 pm
Great job Jay. Now get to listening.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 27 Aug 2014, 10:07 pm
Quote
Oh, if I am not using the  RCA outs, should I have the  amp's low pass slope set to  EXT/12 or does it matter ?  .  Funny, with some  music  I prefer the EXT/12 setting, with other  music I prefer tje 80/24

The EXT/12 setting means the crossover slope is 12db per octave and controlled by the crossover dial on the amp.

The 80Hz/24 setting adds an additional 12db per octave slope at 80Hz plus whatever you do with the dial.

The 50Hz/24 setting adds an additional 12db per octave slope at 50Hz plus whatever you do with the dial.

There is no right or wrong setting.
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 28 Aug 2014, 12:10 am
The sub not only blends sonically with the speakers Jay, but cosmetically too. Very nice! Did you put spikes on the bottom of the H-Frame?
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 28 Aug 2014, 01:09 am
Thanks guys,

Danny, I'll  continue to play with it and see  what works best then, I know it probably shouldn't be but  it is a bit confusing  when  one isn't used to making these adjustments to the slope

bdp24,  yes, I did install inserts in the base for the spikes,  just haven't threaded the spikes in yet althugh they are sitting right here,  Once installed,  the  base height of the  H Frame will be equall to that of the  OB7. 

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 28 Aug 2014, 01:22 am
Jay,

Looks really good. What is the purpose of the 4-pole quick connect?

Mike
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 28 Aug 2014, 01:45 am
Jay,

Looks really good. What is the purpose of the 4-pole quick connect?

Mike

Quick connect/disconnect  the  amp from the cabinet   :lol:   Sorry man, couldn't resist !

2 driver coil leads, 2 servo coil leads, just the one connector.   The female side of the connector is permanently installed in the side of the amp enclosure ,  the leads coming from the cabinet   are attached to the male  side

http://www.parts-express.com/neutrik-nl4mp-speakon-connector-4-pole-panel-mount--092-052
http://www.parts-express.com/neutrik-nl4fx-speakon-spx-cable-connector-4p--092-190

Works well

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 28 Aug 2014, 01:51 am
Hi Jay.
Really nice work.
Now with those subwoofers you will be able to really enjoy the classic:
Fanfare for a common man !

Guy 13

Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 28 Aug 2014, 02:11 am
Quick connect/disconnect  the  amp from the cabinet   :lol:   Sorry man, couldn't resist !

Ha Ha, you funny man  :icon_lol:

Didn't realize you needed 4 wires for the servo units. Did you hard wire the leads to the cabinet so you only have one connection or did you put a female connector on the cabinet as well then make the connecting wires an interconnect with male connectors on both ends? Or would that degrade the signal?

Mike
Title: Re: Dual 12" OB H-Frame Construction
Post by: Ron on 28 Aug 2014, 02:34 am
  Your entire speaker system looks great Jay! You did an excellent job building all of them.  :thumb: Only wish that I lived close enough so that I could see and hear them in person. Thanks for posting pictures during the build for everyone to see.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 28 Aug 2014, 04:38 am
Ha Ha, you funny man  :icon_lol:

Didn't realize you needed 4 wires for the servo units. Did you hard wire the leads to the cabinet so you only have one connection or did you put a female connector on the cabinet as well then make the connecting wires an interconnect with male connectors on both ends? Or would that degrade the signal?

Mike

Not sure how much  the extra connector woould degrade the signal, but no,  I  didn't put a female  connector in both the cabinet and the amp enclosure.  The wires are just hard wired into the cabinet with the male connector  that plugs into the amp enclosure..  For movng, the  wires and connector actually will coil up and  sit inside the lower   rear  "box" ... not that I am planning on movng theiis much, it is  friggin' heavy.

Ron,  thanks  for the comments  man,  I too really wish we were closer so we could  hang out, would be cool  :beer:

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 28 Aug 2014, 04:48 am
Not sure how much  the extra connector woould degrade the signal, but no,  I  didn't put a female  connector in both the cabinet and the amp enclosure.  The wires are just hard wired into the cabinet with the male connector  that plugs into the amp enclosure..  For movng, the  wires and connector actually will coil up and  sit inside the lower   rear  "box" ... not that I am planning on movng theiis much, it is  friggin' heavy.

Ron,  thanks  for the comments  man,  I too really wish we were closer so we could  hang out, would be cool  :beer:

-jay

Hi Jay.
I have hard wired my V1 top and bottom because the Rythmik plate amplifier is attached to the enclosure,
therefore, no need to use those nice looking connectors.
Danny supply them to me with the purchase of the V1 but never used them.
I know the audio purists will be horrified when I tell them that my V1 are on wheels,
but I will not break my back moving those super heavy monsters
and since the little Vietnamese are no help for me,
because they cannot lift anything heavier than a bowl of rice, I cannot rely on them for help
and I have to do it myself.

Guy 13

Title: Re: Dual 12" OB H-Frame Construction
Post by: sortner on 28 Aug 2014, 02:41 pm
Jay,

beautiful looking system..................Any chance we can get a listen on you tube like Ron did, love to hear them sing..

Title: Re: Dual 12" OB H-Frame Construction
Post by: nickd on 28 Aug 2014, 02:50 pm
Nice Work Jay,

I have had the pieces cut for a pair of OB subs for a couple of years now. I think you just inspired me to build them up and order the amps and woofers.

I have boxes already built and the aluminum woofers on hand for a pair of Rythmik sealed servo subs too. But after having the Super V's in my room for a year, the OB bass still has my heart.

I'm also a little jealous of your diffusors. :green: Not sure what they are made of but I like the shape!
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 28 Aug 2014, 05:40 pm
Jay,

beautiful looking system..................Any chance we can get a listen on you tube like Ron did, love to hear them sing..

Strange as it may seem these days, I actually don't have a camera that records decent sound.... I've been  trying  to get a decent sounding video using all the different  devices we have here  for a while now but  not having much luck.  My neice actually  just got one of those  mini, and I mean mini,   video cameas but the sound is awful.  Ron told me he used an HD camcorder ,  I'll have to try and borrow one.

nickd,
I'm already hooked on the OB subs too,  I'm so happy with the results :)
The diffusers were an experiment..... hoping to  replace them one of these days with some of Dave's (PI Audio) diffusers. 
The poly's were easy to make (after exploding the first attempt made with 3/16 ply)  I  ended up making the fronts out of  fiberboard ( I believ you guys down in the US call it masonite?)  with a  2/4" plywood back.      They are bent in 1/3 of a circle, have a 7" segment height,  and the interiors are stuffed with  rockwool.
Used a circle  calculator to determine all the measurements
http://www.1728.org/circsect.htm

Using  a couple of rachet style tie downs and  a few well placed blocks,  the panels weren't difficult to bend and then fasten to the bevel cut plywood  just using screws


Guy, 
I will hae to  have a listen to that   !!

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: corndog71 on 29 Aug 2014, 10:37 pm
... not that I am planning on movng theiis much, it is  friggin' heavy.


I'm really curious about what the final weight is for it.  My single sealed servo sub came out to be around 54 pounds if I remember correctly. 

Your's looks heavier.  It looks killer too!  :thumb: 

Now I really want one!  :drool: :bounce: :notworthy:
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 30 Aug 2014, 12:31 am
Hey corndog71,  thanks  man  :)

The boxes of parts Danny sent were listed at 65 lbs according to UPS,, not sure what  all lthe packing itself would have weighed but I wouldn't think ovelry much.   I used  about 3/4 sheet of   3/4" MDF

I've never heard one of the  sealed servo subs so unfortunately, I can't make any ccomparsions for you

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 30 Aug 2014, 03:05 am
Hi Jay.
My V1 are about 90+ pounds each,
that because all the walls are double thickness and the top part and bottom part are separated
and the Rythmik plate amplifier is built in.
That's the reason why they are still on rollers, I protect my spine.

Guy 13


(http://www.audiocircle.com/image.php?id=104602)
 
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 30 Aug 2014, 04:34 am
Hi Jay.
My V1 are about 90+ pounds each,
that because all the walls are double thickness and the top part and bottom part are separated
and the Rythmik plate amplifier is built in.
That's the reason why they are still on rollers, I protect my spine.

Guy 13


You must have ued that lightweight MDF   :lol:

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 30 Aug 2014, 06:53 am
Here are a couple videos

http://www.audiocircle.com/index.php?topic=128434.new#new

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: ThePriest on 21 Nov 2014, 10:05 pm
Hi Jay.
Just want to say thanks for the nice thread and pics.
I have my own set of GR woofers being delivered across the Atlantic, can't wait to have them finished.
I am in the process of making the frames, and have been using your build as inspiration, as I quite liked the slots in the sides for the baffle.
My own two frames have been glued, and will now need some sanding and filling, before I start priming them.

Cheers

Mikkel
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 22 Nov 2014, 12:52 am
hey Priest
Glad you are finding the thread helpful :)
Using the dado's in the side panels makes assembly a lot easier, not to mention probably adds some streangth. I even thought about adding an extra 1/2" to the top and bottom of the baffle and  cutting a dado in  the top and bottom panels as well but in the end , didn't  go that far.
When you're all done, post  some pics for us   You are going to love  these, still find  it amazing !!

BTW, I've got the 2nd  frame done and recently placed the order for the  parts so soon both will be up and running  :hyper:

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Dec 2014, 12:47 am
Hey folks
Here is a  brief update.   I finally placed the parts order with Danny for my 2nd H-frame.  Received  them all last week and this past weekend  I got it all assmebled, so..... it is up and running  8)

 Right  away, there were  a couple things very apparent 1.  significantly more  "wieght" behind the bass , 2. An increase in both the  depth and width of my sound stage, this I was not expecting at all.  I shot Danny a  mail about this and he said  he has had similar experiences, he suggested playing around with the dampening  settings  as they can have an effect on the size of he stage  (I'm trying the low setting out   now Danny).

I know  bass is supposed to be omni directional but adding the 2nd H-frame definitly seems  to be creating more movement in the reproduction,  you really notice a drummer going   from one side to the other now.  This was present before but not to the same deree.

I listened quite late on Saturday night and didn't seem to notice much difference comapred  to the single H-frame at low volumes but,  listening late  again last night ( the subs now has  some time on it)   I'd have to say there is  even  more behind the bass at low levels.    Guess the bass just seems more  dynamic with more  ooomph

As I mentioned to Danny,  I'm finding the pair very impressive !!

Here's a couple of piccs, one without grills, one without
(http://www.audiocircle.com/image.php?id=110117)

(http://www.audiocircle.com/image.php?id=110118)

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: gregfisk on 10 Dec 2014, 01:00 am
Jay, I remember when you started on this journey.... at least here at the GR Research Circle. Man have you come a long way, look at that nice set up, the speakers and subs look great together and I bet it sounds wonderful now. :thumb:
Title: Re: Dual 12" OB H-Frame Construction
Post by: corndog71 on 10 Dec 2014, 01:36 am
Awesome report!  This is what I'm looking forward to! :bounce: :rock:

Just have to wait to see what my bonus will be before I pull the trigger on the drivers, No Rez, and an amp.

They look great too.  :thumb:
Title: Re: Dual 12" OB H-Frame Construction
Post by: Early B. on 10 Dec 2014, 03:02 am
I really like the grilles on the subs. I'm sure they sound great!
Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 10 Dec 2014, 03:06 am
Jay,

That's one heck of a setup :thumb:. I'm jealous (but I'll get there eventually :eyebrows:).

Mike
Title: Re: Dual 12" OB H-Frame Construction
Post by: Guy 13 on 10 Dec 2014, 03:22 am
Jay,
nice looking and sounding (I'm sure) set up.

Guy 13
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Dec 2014, 04:01 am
Thanks fellas,  I appreciate all the comments.

Corndog,  you're going to love your subs,  they are   wonderful, and with the 8 ohm woofers, you'll be able to get a bit more output. 

Greg,   I  was sitting here listening  to  some tunes tunes on Sunday night  and  was remembering  the exact same thing.   Back when I was trying to decide between the AV and N3 series.  I had built  my first sub that summer and figured I could do a speaker upgrade , I had a  set of Fluance HT  speakers.  I did a google search and  found Danny (GR Research)  and  from there  found  AC . 
 Been lots of  fun not only learning, building and listening, but also getting to know many of you guys :beer:

To the next step  !!



Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 10 Dec 2014, 04:09 am
To the next step  !!

Which is? Enquiring minds want to know ...
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Dec 2014, 05:46 am
Which is? Enquiring minds want to know ...

Sit back,  pop a cold one,, maybe  two,  and enjoy the music !
After that,  who knows  :scratch:

-jay


Title: Re: Dual 12" OB H-Frame Construction
Post by: corndog71 on 10 Dec 2014, 05:47 am
I just noticed the amp stands.  Great idea!  Gives me some ideas.   :idea:
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Dec 2014, 06:22 am
I just noticed the amp stands.  Great idea!  Gives me some ideas.   :idea:

Yeah  they  were  just quickly thrown toether with some scraps of 1/2" MDF  and leftover 2x2's from a dog house project.  A few quick cuts, some router work, and some black paint . Simple but they work  just   fine,  and my Minibuss found a home on the bottom shelf of one

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: ThePriest on 10 Dec 2014, 06:30 am
Nice work, Jay!

I am really looking forward to get my own pair up and running.
Painting starts in the weekend (mother-in-law is visiting, so I have to have something to do  :lol: ).
The amps are almost ready, one is finished, the box is ready for the other one.

Cheers!

The Priest
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 10 Dec 2014, 06:34 am
I just noticed the amp stands.  Great idea!  Gives me some ideas.   :idea:
You don't want to get the Rythmik plate amps too far from the Servo drivers. In fact, the closer the better.
Title: Re: Dual 12" OB H-Frame Construction
Post by: ThePriest on 10 Dec 2014, 06:52 am
What is 'too far'?

I have kept as much as possible of the cabling from the plate amp itself, so how much speaker cable would be too long? 1 meter? 2?

Cheers,

ThePriest
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 10 Dec 2014, 09:12 am
What is 'too far'?

I have kept as much as possible of the cabling from the plate amp itself, so how much speaker cable would be too long? 1 meter? 2?

Cheers,

ThePriest
Good question. Danny has commented on the question before, maybe he will now.
Title: Re: Dual 12" OB H-Frame Construction
Post by: lacro on 10 Dec 2014, 02:05 pm
Wow Jay!

Are you trying to catch up with Mike? :green: Nice set-up :thumb: It looks like it's a fairly small room for all those speakers, must sound awesome.. What are the big black boxes on the wall, is that room treatments? Also, is that a Crown power amp sitting on the floor?
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 10 Dec 2014, 04:09 pm
What is 'too far'?

I have kept as much as possible of the cabling from the plate amp itself, so how much speaker cable would be too long? 1 meter? 2?

Cheers,

ThePriest

Shorter is better. I use a SpeakOn connector at the end of the factory wiring coming off of the amp. Then plug that into the female SpeakOn that gets mounted to the back of the H frame.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 10 Dec 2014, 04:30 pm
I thought I read in one of the threads that a few feet was okay for  leads to the H-frame.   Mine are 4' using   the 16 ga solid copper  Danny sells.  I use the same connectors Danny mentions but   I have the cables soldered direct tothe   H-frame and the male plug at the end.  Then I mount the female side in the amp box.

Larry
The room is It is  18' x 12', wish it were a couple feet wider. Those are  poly diffusers behind the  OB7's which I hope to eventually replace with some  "MR T" diffusers from PI Audio.   Nope, no Crown amp

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 10 Dec 2014, 04:49 pm
A few feet is okay. Shorter is better.
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 12 Dec 2014, 02:58 am
I thought I read in one of the threads that a few feet was okay for  leads to the H-frame.   Mine are 4' using   the 16 ga solid copper  Danny sells.  I use the same connectors Danny mentions but   I have the cables soldered direct tothe   H-frame and the male plug at the end.  Then I mount the female side in the amp box.

Larry
The room is It is  18' x 12', wish it were a couple feet wider. Those are  poly diffusers behind the  OB7's which I hope to eventually replace with some  "MR T" diffusers from PI Audio.   Nope, no Crown amp

-jay
12' IS a very common room width. My room is a little wider at 13, but I too would love a foot or two more on each side of the left and right front speakers. My dream room would have a 10' ceiling, with the width and depth in the "Golden Ratio" proportions (see the Cardas site for details) of 1 : 1.6 : 2.6, which would make the width and depth 16' and 26' respectively. Dream is right! The only rooms like that I've been in are the ones Brooks Berdan built for his hi-fi shop (Brooks Berdan Ltd. in Monrovia, CA) and his son Brian Berdan just built for his new shop in Pasadena, CA, Audio Elements. Those dimensions give the most even spread of room modes and lowest resonant signature possible in an enclosed space.
Title: Re: Dual 12" OB H-Frame Construction
Post by: glynnw on 13 Dec 2014, 02:48 am
I am slowly building one of these sub cabinets with an eye to finishing and ordering the electronics in a month or so.  For the outer walls I am using 2 pieces of 3/4" MDF to get a 1 1/2" wall.  I am using 6 1/2 " as the depth of each woofer well as per the plans  but want to make the outer of the 2 MDF pieces 1 " wider to give a 1/2" overhang on each end to frame a grill cloth.  Will extending the depth of each woofer well by 1/2" seriously change the sound?  I can give up the 1/2" extension - I just think a frame around the grill cloth would look nice. Or should I adjust the size of each wall piece so that the final depth is still only 6 1/2" with a grill attached"?
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 13 Dec 2014, 06:08 am
I am slowly building one of these sub cabinets with an eye to finishing and ordering the electronics in a month or so.  For the outer walls I am using 2 pieces of 3/4" MDF to get a 1 1/2" wall.  I am using 6 1/2 " as the depth of each woofer well as per the plans  but want to make the outer of the 2 MDF pieces 1 " wider to give a 1/2" overhang on each end to frame a grill cloth.  Will extending the depth of each woofer well by 1/2" seriously change the sound?  I can give up the 1/2" extension - I just think a frame around the grill cloth would look nice. Or should I adjust the size of each wall piece so that the final depth is still only 6 1/2" with a grill attached"?
I had the exact same idea for my W-frames, and extended the outer 3/4" MDF layer 1" past the inner layer at the front, to allow for an inset 3/4" thick grill frame. It gives the cabinet the look of the 50's-60's (and even 70's) speakers, like Klipsch, AR, Dynaco, Advent, etc. speakers had (Klipsch STILL has that look in it's classic series). That style cabinet (with the grill inset into the front of the cabinet) went out of favor when research discovered the problem of diffraction caused by the sound from the drivers reflecting off of the front edges of the cabinet, solved by having the front baffle not inset into the cab. At subwoofer frequencies, however, diffraction is not a concern. That 6-1/2" depth is a compromise between supporting the lowest possible frequency while not creating too much of a cavity resonance. The depth of the driver cavity doesn't have to be exactly 6-1/2"---You can make it an inch shallower or deeper without incurring a serious penalty in sound quality or quantity.
Title: Re: Dual 12" OB H-Frame Construction
Post by: glynnw on 13 Dec 2014, 05:30 pm
Thanks.  Just what I needed to hear since 1 of the boards is already glued into place.
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 14 Dec 2014, 04:44 am
You may have already noticed this, but there is one mistake in the plans for the H-Frame. The dimension given for the depth of the frame is 13.5", which is incorrect. It is actually 14"---6.5" for each driver cavity plus 1" for the baffle thickness. Unless I'm misunderstanding something!
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 14 Dec 2014, 06:43 am
I think the Super-V only used a 3/4" baffle making the depth  13.75".  I don't see the point of making the baffle any thicker as there is really no panel  there to resonate, the coutouts and drivers pretty much take up the whole   area.

If you've got the  material  , making  it thicker isn't going to hurt but  not necessary.

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: bdp24 on 14 Dec 2014, 06:53 am
I think the Super-V only used a 3/4" baffle making the depth  13.75".  I don't see the point of making the baffle any thicker as there is really no panel  there to resonate, the coutouts and drivers pretty much take up the whole   area.

If you've got the  material  , making  it thicker isn't going to hurt but  not necessary.

-jay
The 1" spec for the baffle came not from me but from the plans for an H-Frame found in the listing for the GR-12-16FR driver on the GR Research website. I brought it to the OP's attention only in case he is building his H-Frame from those plans, and wanted to let him know that if he uses the 13.5" spec to cut his top piece, it will be 0.5" short. That 13.5" spec, were it to be correct, and assuming that both driver cavities are indeed 6.5" deep, would require the baffle be 0.5" thick, surely not something Danny would suggest.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 14 Dec 2014, 07:13 am
I mentioned it only in case the OP is building his H-Frame from the plans found in the GR-12-16FR driver's listing. If he uses the 13.5" spec to cut his top piece, it will be 0.5" too shallow.

Ahh,  you're right, hadn't seen those plans before.  Good catch.   A bit different  than the Super- V drawing

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 14 Dec 2014, 06:07 pm
Error noted and corrected.
Title: Re: Dual 12" OB H-Frame Construction
Post by: gab on 14 Dec 2014, 07:02 pm
Error noted and corrected.

I think you missed the note at the top of Pg 3 Front View. It is currently "Top panels is 16” wide and 13.5” deep" and if I understand correctly it should be "Top panels is 16” wide and 14” deep"

gab
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 14 Dec 2014, 07:35 pm
I think you missed the note at the top of Pg 3 Front View. It is currently "Top panels is 16” wide and 13.5” deep" and if I understand correctly it should be "Top panels is 16” wide and 14” deep"

gab

Also noted and corrected.
Title: Re: Dual 12" OB H-Frame Construction
Post by: ZAKski288 on 14 Dec 2014, 07:44 pm
Where are the H-Frame Plans available. Thanks Guys,  ZAK
Title: Re: Dual 12" OB H-Frame Construction
Post by: ZAKski288 on 14 Dec 2014, 07:49 pm
  :duh: :duh: I found them.  Are there any advantages of going with three per side. Thanks  ZAK
Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 14 Dec 2014, 07:50 pm
Where are the H-Frame Plans available. Thanks Guys,  ZAK

You can find them here http://www.gr-research.com/pdf/H-frame%202.pdf
Title: Re: Dual 12" OB H-Frame Construction
Post by: ZAKski288 on 14 Dec 2014, 07:55 pm
Thanks mlundy57,  I found them. Thanks ZAK
Title: Re: Dual 12" OB H-Frame Construction
Post by: mlundy57 on 14 Dec 2014, 08:00 pm
Shorter is better. I use a SpeakOn connector at the end of the factory wiring coming off of the amp. Then plug that into the female SpeakOn that gets mounted to the back of the H frame.

Where would you mount the connector at the back of the H-Frame?
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 14 Dec 2014, 08:17 pm
Where would you mount the connector at the back of the H-Frame?

You can mount the connector on the inside back corner of the side panel.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 15 Dec 2014, 03:39 am
Are there any advantages of going with three per side. Thanks  ZAK

More output and overall , you'd be working each driver less to reach a given SPL so  less distortion/cleaner.  At normal listening levels  ( relative I know)   mine  are  being worked very little

-jay
Title: Re: Dual 12" OB H-Frame Construction
Post by: ZAKski288 on 16 Dec 2014, 02:21 am
Thanks Captainhemo for info. Your setup is awesome, and I'll bet it sounds incredible.  ZAK
Title: Re: Dual 12" OB H-Frame Construction
Post by: Odal3 on 4 May 2016, 02:55 am
 I will finally join the servo sub club. I will also start with a dual 12" H-frame and I'm very excited to get started! The second one will be added at a later point. Will use this build to improve my poor wood working skills. If all goes wrong, my back-up plan is of course to buy the the nice looking CNC cut frames you offer.

Captainhemo -
I noticed on the GR Research drawing that the brace location is off-set between front and back but it looks like the dado you cut is straight across? Is the only difference the total height of the H-frame - 26 3/4" vs 26"?

Thanks again to you and everyone else who has shared their builds for the inspiration!
Title: Re: Dual 12" OB H-Frame Construction
Post by: Captainhemo on 4 May 2016, 03:55 am
Saves you  .75"   in height if you offset them.
 The ones I've been building (these and the CNC ones) use the  exact same size "chamber"  front  and rear, 13" x 13"  instead of the 13"  x 12.25" you get with the offset braces.

You're in for a real treat with these subs  :beer:

jay.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Odal3 on 4 May 2016, 04:48 pm
Thanks Jay!
Title: Re: Dual 12" OB H-Frame Construction
Post by: Bobusm on 6 May 2016, 07:39 pm
I am hopefully building one of theses as well as got hold of a370 servo amp here in Uk which is rather rare. 

Not decided on what to build yet. I would love to build H frame open baffle but dont really have a lot of space for it and it will probably end up in corner of the room. Will this limit the performance of this sub?
I also have pretty much ideal sealed box for my current sub about 50 liter 2 cu ft or so in size. If I just get servo driver for it it will save me lot of hassle. What is the main difference between sealed and OB?

I am using  N3's on end of amp camp. Listening on low levels most of the time - late night so spl is not an issue. Just want to add bit of extra dimension to the bass.

Thanks
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 6 May 2016, 07:49 pm
I can send you an amp and woofer or woofers. No problem.

The open baffle subs need breathing room. Near a corner is not going to give you good results.

Our sealed box SW-12-04 servo woofer needs just 1.5 to 1.8 cubic feet of air space. You might be able to use your current box for them if the through hole for the woofer is no bigger than 11" across. You can also line the inside of your box with a thin layer of MDF to stiffen it up and take up a little air space at the same time.

It sounds like the sealed box version might be more ideal for your application.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Bobusm on 6 May 2016, 08:42 pm
Hi Danny.

Thanks for quick reply. Just measured the box again and it seems like it is around 2cu ft without the driver (not sure if you take this into  measurements or no) I am not sure if I can add any braces as it already have 2 braces going accross and it is all build from 1" material (bought already built so not sure what it is - looks like something solid not MDF). Box is bery solid and braced very well hence I was thinking it should work. Hole is tiny bit over 11" so it should work ok.

I think I will go with sealed for now due to the cost involved with shipping and tax etc. You should really open some european branch Danny as there would be definitelly lots of interest for the Subs and kits.

Now I just need to find second hand driver and get some cheap courier from Us to Uk :-)

Title: Re: Dual 12" OB H-Frame Construction
Post by: Hank on 8 May 2016, 08:06 pm
Danny wrote: 
Quote
Near a corner is not going to give you good results.
Danny, what's the minimum distance from a corner?
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 8 May 2016, 09:39 pm
Danny wrote:  Danny, what's the minimum distance from a corner?

The open baffle subs really need to be out from the corner three feet or more.  And treating the corners with some tube traps of some kind will really help as well.
Title: Re: Dual 12" OB H-Frame Construction
Post by: Danny Richie on 8 May 2016, 09:44 pm
Hi Danny.

Thanks for quick reply. Just measured the box again and it seems like it is around 2cu ft without the driver (not sure if you take this into  measurements or no) I am not sure if I can add any braces as it already have 2 braces going accross and it is all build from 1" material (bought already built so not sure what it is - looks like something solid not MDF). Box is bery solid and braced very well hence I was thinking it should work. Hole is tiny bit over 11" so it should work ok.

That is actually what I'd call very mildly built. Cutting you some pieces of MDF and gluing them in with liquid nails will really help. And on that I'd line it with No Rez or at least some industrial floor tiles.

I'll get you a shipping quote on Monday.
Title: Re: Dual 12" OB H-Frame Construction
Post by: sglau on 17 Nov 2019, 10:08 pm
That is some awesome build quality in these frames for the OB 12's. I might resurrect my two pairs and rebuilt as you have! How did the final finishing completed set come out and do you have pic you can post?