Open Baffle H Frame with Built in Amp

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russellberg

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Open Baffle H Frame with Built in Amp
« on: 25 Nov 2020, 04:06 am »
I am starting an open baffle sub and I am using wood from a cherry tree that a friend cut down.  I got someone to rough mill the tree into 3 ½" boards and it has been drying for 2-3 years.  I am ready to use it now.  It may not look like much yet but the cherry wood really shines once it is dressed properly.  Here is the design that I have come up with.  I am planning to have both drivers facing forward.


The baffle will be 1½" of MDF and I will paint it black.  Everything else is going to be cherry.  I am not going to be using no-res.  I may be wrong but I am feeling like the mass of the 2-2½" side, top and bottom panels will limit resonance.  Also, the look of the exposed foam isn't really for me.  The amp will be mounted in the bottom section of the build.  I am pairing this with X-SLS Encores so I don't need it to act as a stand for bookshelves.


Can you see the open baffle H frame in that chunk of wood? :)   Its fun to take what is just this side of a tree and turn it into something like a speaker.




I had a lot of checking in some of the raw boards so I could sometimes break them apart, sometimes I had to saw them apart.  Then I would mill a clean edge on each one and glue them back together to get the wide 14-15"panels.  You always have to oversize your pieces in a project like this because there is always wood movement once you start sawing.


I would cut to rough length with the circular saw then strike a string line down one edge.  Then I ran it through the band saw to get one relatively straight edge.  This picture doesn't show the correct sequence, I can't remember why, but next I would typically take it tow the table saw to cut the wane off of the other edge of the board.


The boards are 3½" thick so I had to run it through the table saw once, then flip it over and run it through again to get a through cut. 


This gave me one edge that was pretty close to flat and I cleaned it up my jointer and a hand plane.


This is why I spent so much on a bandsaw.  To be able to cut through 13¼" of solid cherry is a very cool thing.


I didn't take a picture with the thickest board but here I am resawing a much smaller piece.  When I did the big piece the red blade guide is retracted all the way up into the saw.


This is as far as I've gotten.  Its all the pieces I need for one open baffle H frame with the sub mounted underneath.  My garage is not heated so I have brought everything inside so that I can get any last wood movement happening.  When you resaw wood you release a lot of tension within the wood and it is not uncommon for even quite dry wood to move after resawing.  Everything is well oversized so that I can mill out any cupping, twisting, or bowing.  Much of it will have to done with hand plane because my planer is not big enough for some of these pieces but I really enjoy the hand work.  You will notice the checking that is still present in some of the long side pieces.  I am going to fill them with black epoxy and then inset some purple heart bow-ties to hold the cracks in place.  I just got the shipping notice from Danny for my drivers and the amp so I am excited for them to arrive!


Jon L

Re: Open Baffle H Frame with Built in Amp
« Reply #1 on: 25 Nov 2020, 04:42 am »
I got someone to rough mill the tree into 3 ½" boards and it has been drying for 2-3 years.  I am ready to use it now. 
Love that!
Making just one, or hopefully two?

russellberg

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Re: Open Baffle H Frame with Built in Amp
« Reply #2 on: 25 Nov 2020, 04:46 am »
Love that!
Making just one, or hopefully two?
Just one for now is all the budget will allow.  I have already built one of Danny's sealed subs so I am hoping to integrate the open baffle unit with my sealed sub to give me more even and responsive bass response.

aldcoll

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Re: Open Baffle H Frame with Built in Amp
« Reply #3 on: 25 Nov 2020, 04:59 am »
Looks like a great wood project and then I keep going back to what is that receiver up on the shelf? 

I will be watching for updates and pictures.  Man I remember wanting all those eq settings on my stereo to :thumb:

russellberg

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Re: Open Baffle H Frame with Built in Amp
« Reply #4 on: 25 Nov 2020, 05:03 am »
Looks like a great wood project and then I keep going back to what is that receiver up on the shelf? 

I will be watching for updates and pictures.  Man I remember wanting all those eq settings on my stereo to :thumb:
Haha, can't believe you noticed! That is a 30 year old Radio Shack unit!  Still makes sound but I don't use it that often as I am almost always listening to audio books when I am working with wood.  With the little earbuds I can keep my ear protection on.

russellberg

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Re: Open Baffle H Frame with Built in Amp
« Reply #5 on: 3 Dec 2020, 05:13 am »
Well, it is starting to look like a sub.  I decided to do the baffle out of two ¾" layers of MDF and paint it black.  Am I ever glad I did.  I am usually an all wood guy but I think this contrast really looks good.


Here is a dry fit before I had cut the dado for the middle dado.


Hopefully we can learn from each other's mistakes.  Here I screwed up by cutting the dado on the wrong side of the line so I ended up with a dado that was double the thickness it should have been.  I will cut an extra piece and fill it in.  I've got some pieces with similar grain so I don't think it will be too noticeable.


I did the finish on the inside parts before I did the glue up.  I sand to 220, then buff with two different compounds, and then buff in the wax.  The finish is so smooth and lustrous and I love the way it feels and looks but it would be impossible to get my buffing wheel inside the boxes so I have to do it first.


I had put the green masking tape on to prevent the finish getting on to the parts of the wood where I need the glue to go.  Glue will not bond properly to wood that has been waxed.


The glue up is a little tense with 7 pretty tight dadoes that all have to line up correctly but it went together pretty nicely.  I tried to use the minimum amount of glue but I still had a little squeeze out.  I waited until it was nearly hard, kind of rubbery feeling and then it scrapes out pretty nicely.  It comes off the waxed surfaces very easily.  I'm really happy with how it is looking so far.  The amp will go in the cavity at the bottom.


I also got the frame for mounting the amp cut out and installed.  I made this with ¼" cherry plywood laminated on a piece of ¾" MDF.  Every other piece of wood in this design has the grain running in the same direction.  I am hoping that this, along with the fact that all the wood came from the same tree will help keep any wood movement consistent so that it isn't pulling against itself.  With this piece and the corresponding piece that will cover the front of the amp cavity  I could not line up the grain direction so I did it with plywood and MDF which will not move.  This was also part of the reason for making the baffle out of MDF.  I'm getting close to the finish line and I'm excited to hear it.  Any questions let me know.

Peter J

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Re: Open Baffle H Frame with Built in Amp
« Reply #6 on: 3 Dec 2020, 03:15 pm »
Looking good! I'll bet the realization on mis-cut dado was a moment. I've done (perhaps more than) my fair share. The good news is we get to learn, eh? Thanks for taking us along for the ride. I really enjoy reading and looking at other people's projects.

russellberg

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Re: Open Baffle H Frame with Built in Amp
« Reply #7 on: 3 Dec 2020, 10:18 pm »
Looking good! I'll bet the realization on mis-cut dado was a moment. I've done (perhaps more than) my fair share. The good news is we get to learn, eh? Thanks for taking us along for the ride. I really enjoy reading and looking at other people's projects.
I know that I have learned more from figuring out how to fix my mistakes than I do on a project that goes smoothly.

2bigears

Re: Open Baffle H Frame with Built in Amp
« Reply #8 on: 3 Dec 2020, 11:43 pm »
 :D a simple trick is a little X on cutting side.  Just saying. That sub is gonna be very nice. Very heavy.  :D

Jonathon Janusz

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Re: Open Baffle H Frame with Built in Amp
« Reply #9 on: 4 Dec 2020, 02:23 am »
I've thought for a while that mounting the amp this way would be the nicest way to do it from the perspective of a finished-looking speaker.  Either leaving the amp in a separate box or even those that had the amp laying flat in a box that was somehow attached to the back of the frame just seemed to be a compromise/workaround to mounting the plate amp for what it is - a plate amp (and this keeps the wiring runs to the drivers hidden, neat, and as short as can be too).  I'm glad to see somebody put it together this way.  That is going to be a really nice looking subwoofer! :thumb:

Early B.

Re: Open Baffle H Frame with Built in Amp
« Reply #10 on: 4 Dec 2020, 04:54 am »
I've thought for a while that mounting the amp this way would be the nicest way to do it from the perspective of a finished-looking speaker.  Either leaving the amp in a separate box or even those that had the amp laying flat in a box that was somehow attached to the back of the frame just seemed to be a compromise/workaround to mounting the plate amp for what it is - a plate amp (and this keeps the wiring runs to the drivers hidden, neat, and as short as can be too).  I'm glad to see somebody put it together this way.  That is going to be a really nice looking subwoofer! :thumb:

The problem for many would be the added height which may not be ideal if you plan to build dual subs to set monitors on top of them. However, the monitors can perch on stands close to the subs, but you encounter another kind of clutter issue. Nevertheless, I prefer this approach and would angle monitors downward to compensate for the height. Just need longer speaker cables to reach up to the monitors.

russellberg

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Re: Open Baffle H Frame with Built in Amp
« Reply #11 on: 4 Dec 2020, 05:06 am »
:D a simple trick is a little X on cutting side.  Just saying. That sub is gonna be very nice. Very heavy.  :D
Absolutely, I use that trick a lot, until I get careless and I don't ;)

russellberg

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Re: Open Baffle H Frame with Built in Amp
« Reply #12 on: 4 Dec 2020, 05:10 am »
The problem for many would be the added height which may not be ideal if you plan to build dual subs to set monitors on top of them. However, the monitors can perch on stands close to the subs, but you encounter another kind of clutter issue. Nevertheless, I prefer this approach and would angle monitors downward to compensate for the height. Just need longer speaker cables to reach up to the monitors.
Yes, I am running it with X-SLS's so the height isn't an issue for me.  I just couldn't see having the amp in a box on the floor, plus my wife would never go for it. 

Early B.

Re: Open Baffle H Frame with Built in Amp
« Reply #13 on: 4 Dec 2020, 05:27 am »
I just couldn't see having the amp in a box on the floor, plus my wife would never go for it.

I got three plate amps on the floor. Yeah, they're in the way. I have to step over wires and power cords every time I power up my system. Dust magnets, too. One of my amps lies on the floor because the power cord wants to come undone when the amp is upright. It's a small price to pay for the incredible sound, though. You're gonna love your sub.

ThePriest

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Re: Open Baffle H Frame with Built in Amp
« Reply #14 on: 4 Dec 2020, 09:46 am »
Beautiful work! I love the look and the cherry wood.
I have had a few amplifiers with front panel in cherry, so nice.

Regarding no-rez or similar: While I don't think you will have problems with resonances in the wood, the function of the foam part is actually to lower air speed along the sides of frame. These create artefacts in the sound. I noticed a big improvement in the precision of the bass when I lined my frames with a foam not dissimilar to no-rez.

So, you might want to try it out. You can mount foam pieces temporarily with double sided tape or similar.

Looking forward to see your prgogress!

/The Priest

Jonathon Janusz

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Re: Open Baffle H Frame with Built in Amp
« Reply #15 on: 4 Dec 2020, 06:05 pm »
The problem for many would be the added height which may not be ideal if you plan to build dual subs to set monitors on top of them. However, the monitors can perch on stands close to the subs, but you encounter another kind of clutter issue. Nevertheless, I prefer this approach and would angle monitors downward to compensate for the height. Just need longer speaker cables to reach up to the monitors.

Interesting that you made this point this way.  Based on reading this forum for quite a while, I get the impression that it is actually a minority of people using these subs as monitor stands and the exception to the rule seems most often folks doing one of Danny's designs intended to integrate an upper and lower frequency section (like the V2, Super-V, Super-7).  The nx-monitors and super-minis it seems were kits made up in retrospect to accommodate folks that needed (or wanted) to compromise to get as much sound in as little floor footprint as possible (accepting that there would be a meter of space to stash the amp on the floor behind the sub in any case because the subs are OB). 

It is looking at what people have been mostly building/buying that brought me to surprised that someone hadn't done this sooner.  I also think it is something to consider for Danny going forward if statement speakers like the line forces are going to be finished-production rather than kit speakers.  Having a triple stack plus amp of height (effectively a quad driver height speaker) in a sub tower to go along with speakers like the line forces or nx-tremes for that matter I think would make a final product more in line with the priorities of people in the market for such speakers (where size of the room isn't an issue but reducing the number of boxes scattered on the floor aesthetically might be a higher priority).

Regardless, I still think this will be a very cool looking sub tower!  :thumb:  I've said it before and will say it again that I admire folks who can build really great stuff like this.

russellberg

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Re: Open Baffle H Frame with Built in Amp
« Reply #16 on: 4 Dec 2020, 08:05 pm »
Regardless, I still think this will be a very cool looking sub tower!  :thumb:  I've said it before and will say it again that I admire folks who can build really great stuff like this.
Thank you so much for your kind words.  The creative burst I get from making this stuff provides a real lift to my day.  I was inspired by some other people on here who have done versions of this with the amp integrated into a taller version so other people have done it, but I haven't seen many.

Early B.

Re: Open Baffle H Frame with Built in Amp
« Reply #17 on: 4 Dec 2020, 09:18 pm »
Interesting that you made this point this way.  Based on reading this forum for quite a while, I get the impression that it is actually a minority of people using these subs as monitor stands and the exception to the rule seems most often folks doing one of Danny's designs intended to integrate an upper and lower frequency section (like the V2, Super-V, Super-7).  The nx-monitors and super-minis it seems were kits made up in retrospect to accommodate folks that needed (or wanted) to compromise to get as much sound in as little floor footprint as possible (accepting that there would be a meter of space to stash the amp on the floor behind the sub in any case because the subs are OB). 

Yeah, since Danny has recently introduced several OB-style monitors, more people will likely use the subs as stands. Nevertheless, there's value in keeping subs as short as possible for practical reasons such as weight, mobility, WAF, and reduced sonic interference. It may also be a good practice to separate plate amps from subs to eliminate vibrations to the amp. With all that being said, I want to get in the queue to commission Russell to build a pair for me. 8)


   

Captainhemo

Re: Open Baffle H Frame with Built in Amp
« Reply #18 on: 4 Dec 2020, 11:42 pm »
If there was interest,  we might  do something up  with our triple kits ( turn into  a dual with  integrated amp section)  or  quads ( turn into  triples with   integrated amp section).....    ......     :scratch:
Danny has always   suggested keeping the amps separate if at all possible so.....

jay

Hobbsmeerkat

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Re: Open Baffle H Frame with Built in Amp
« Reply #19 on: 4 Dec 2020, 11:50 pm »
If there was interest,  we might  do something up  with our triple kits ( turn into  a dual with  integrated amp section)  or  quads ( turn into  triples with   integrated amp section).....    ......     :scratch:
Danny has always   suggested keeping the amps separate if at all possible so.....

jay

Could always section off part of the amp chamber to be filled with sand or something. May also help with balancing, esp when all 3 drivers are facing forward. :scratch: