[Vapor Audio]

This is what I should have done from the beginning 

So I started off with 2 M-165x's and a T2 in a 1.65 cu/ft box.  I made it into a 2.5 way, but quickly realized that it's a waste to use them in that function - the 165x drivers natural response curve has some baffle step 'built in'.  I ended up with a system that did sound pretty good, but was pretty thick on the lower midrange and upper bass.  I just kept thinking I should have made these things a MTM.

Well, I'm going one step better! 

The idea really just snapped into my head yesterday after a little forum Q&A with Danny.  I have enough room and volume in my cabinets to make this thing a MTMWW!  2 M-130/16's and a T2 in the upper MTM, sealed in .35 cu/ft ... and then use the 2 M-165x up to about 200hz in a 1.3 cu/ft vented.  I was bi-amping already, so just add my Behringer DCX2496 and actively cross between the lower half and the MTM, then use the already perfected AV-3 network for the MTM. 

I really like the M-130/16 specs, that extra Bl should give a bit more slam and impact that I love in my vocals and instrument ranges ... and the pair of 165x's move a ton of air.  I'm sure this thing, bi-amped with 150wpc won't have any problem re-arranging pictures on the wall. 

I'm pretty excited to get going, I think this will be the speaker I was hoping for at the start.  It also didn't help that I had one bad tweeter, which I sent back to Danny today

I'll be adding a layer of 3/4" Baltic Birch ply to the front baffle, these cabs could use it.  I'll then cut a bevel edge or roundover and recover the front with some killer Bubinga veneer I have.  Since I'm a professional photographer, count on lots of pics!

[Danny Richie]

Please keep us up to date on this project. It should be very interesting.

[Pierre]

So I started off with 2 M-165x's and a T2 in a 1.65 cu/ft box.  I made it into a 2.5 way, but quickly realized that it's a waste to use them in that function - the 165x drivers natural response curve has some baffle step 'built in'.  I ended up with a system that did sound pretty good, but was pretty thick on the lower midrange and upper bass.  I just kept thinking I should have made these things a MTM.

 

I'm glad I'm not the only one. I'm working on a small sealed 2-way, to be used near a wall, and have been having the same problem with the lower mids/ upper bass being pronounced. The way the diffraction properties of the box and the native response of the M165X sum together seems to make it more difficult than normal for me.  Just a cap and a coil isn't going to work on this project.

That being said I am making progress at the cost of many components. I'm up to 4th order electrical low pass and 3rd order electrical high pass for a BW5 acoustic response. I believe I have a keeper with the last revision.
Pierre

[Vapor Audio]

I think Danny would tell you that's way to many components and complexity for his drivers.  You gotta think simple ... really simple 

BTW, got my box today from Danny - 4 M-130/16's and the AV/3 network components with Sonicap upgrade.  I'll have something to do this weekend now, lots of box rebuilding and putting together the networks!

Once my parts arrive from down under, I'm building a 4 channel amp with embedded crossovers tailored for this projet (I hate how messy the Behringer is).  The amp modules are SKA GB150D, proclaimed to be one of the cleanest and most detailed Class AB designs around.  I expect the combination to be exceptional!  But boy do I have a lot of work to do 

[Vapor Audio]

Things are moving along!

These cabs were the same ones used when I had them setup as a 2.5 way, they started life as Wharfedale Emerald 87's.  The cabinet originally had a .65 cu/ft upper section, and a 1.1 cu/ft lower section, with a vertical window brace.  For this implementatioin I cut off the front baffle with a jigsaw to make re-working the guts possible.  I then made the top section a .35 cu/ft sealed enclosure (for the MTM section) and the bottom a 1.2 or so cu/ft that will be vented (for the pair of 165x's) - the bottom chamber volume extends upward behind the top section.  I also added quite a few horizontal braces you can see in the picture using dowels.

Next was the fun part, I used a generous layer of this stuff to glue down a layer of 1lb per sq/ft mass loaded vinyl

http://www.greengluecompany.com/

After I covered all internal walls with the glue and MLV, I put down some sections of Sonic Barrier you can see in the picture.  I know, Danny doesn't like the PE Sonic Barrier, but I think with this application it'll be a completely dead enclosure!  Next I'll screw down one front baffle of 3/4" baltic birch, then laminate another layer on top of that with the green glue.  You can see in the shot one box is covered with Bubinga veneer, after I get the new baffle on, I'll re-do both enclosure with the Bubinga and put polished poly finish on it

Thanks to my wife for not throwing a fit while doing all this on the kitchen floor!

[Danny Richie]

Looks good.

I know, Danny doesn't like the PE Sonic Barrier, but I think with this application it'll be a completely dead enclosure!

Yea that stuff is of no value. It has no damper or resonance control effectiveness. The suspended barrier can also mass load the woofers some and have an adverse effect. A layer of foam would be just as effective with no adverse effect.

I can't wait to see how these turn out for you.

I sent out some more goodies to you today.

[Vapor Audio]

Looks good.

I know, Danny doesn't like the PE Sonic Barrier, but I think with this application it'll be a completely dead enclosure!

Yea that stuff is of no value. It has no damper or resonance control effectiveness. The suspended barrier can also mass load the woofers some and have an adverse effect. A layer of foam would be just as effective with no adverse effect.

I can't wait to see how these turn out for you.

I sent out some more goodies to you today.

I know that's what you say about the Sonic Barrier, but would be curious to know if any real testing has been done.  I have some Whispermat 2 as well, and the PE stuff sure looks a lot like it ... and isn't NoRes essentially the same thing just without the bottom open cell foam layer?  I figure with the MLV layer I put under it, I've essentially created Blackhole 5 with a much thicker bottom layer.  It seems like it should work, and the knuckle test says it's really dead ... but what do I know 

I'll be looking for the other goodies, should have the cabs ready in a couple days!  I'm waiting on my amp and crossover kits, but will just use the Behringer with my 5 channel amp in the meantime for active bi-amping.

[Danny Richie]

I figure with the MLV layer I put under it, I've essentially created Blackhole 5 with a much thicker bottom layer.

You did good with the MLV layer. That is what will give you your resonance control and damping of the box. Blackhole 5 is similar. I still like the Blackhole 5 best in sub-woofer cabinets.

I know that's what you say about the Sonic Barrier, but would be curious to know if any real testing has been done.

Yes, I had resonance control testing done on MDF by a couple of different companies and have a stack of different types of materials that were tested. I even have some with lead lined barriers. 

I have some Whispermat 2 as well, and the PE stuff sure looks a lot like it ... and isn't NoRes essentially the same thing just without the bottom open cell foam layer?

Nope. Sonic Barrier and Whispermat are products designed to block sound from penetrating from one side of it to the other. This is ideal for walls and industrial applications.

In a speaker cabinet we really don't have as much of a problem with sound passing "through" the cabinet walls.

What we have is a resonance caused by rapid pressurization and de-pressurization of the box. Thick of the box as a tining fork. Hit it hard at the right frequency and you excite it. With different panels being different sizes it can actually have several different resonance points at once.

Sonic Barrier and Whispermat have no damping layer against the enclosure wall to dampen that resonance. The cabinet walls are still allowed to resonant independently of the barrier that is suspended on it.

The suspended barriers are typically just a sheet of vinyl too.

No Rez uses a heavy damper that is a asphalt composite that will deaden the box walls and eliminate the resonance. Its damping layer is nearly twice as thick as the one used on Blackhole 5. It is very effective and less expensive than Blackhole 5.

[Vapor Audio]

You did good with the MLV layer. That is what will give you your resonance control and damping of the box. Blackhole 5 is similar. I still like the Blackhole 5 best in sub-woofer cabinets.

Good, glad you think so.  I'm surprised nobody has heard of that Green Glue, I've mentioned it quite a few times on a few boards and nobody has used it.  When it dries it almost feels like sorbothane.  I have a feeling in the right applicaton it could be a great help, who knows if I used it in the 'right application' though.

Yes, I had resonance control testing done on MDF by a couple of different companies and have a stack of different types of materials that were tested. I even have some with lead lined barriers.

You should publish that kind of stuff on your website, people like me would LOVE to read the results.

How did the lead do?

Nope. Sonic Barrier and Whispermat are products designed to block sound from penetrating from one side of it to the other. This is ideal for walls and industrial applications.

In a speaker cabinet we really don't have as much of a problem with sound passing "through" the cabinet walls.

What we have is a resonance caused by rapid pressurization and de-pressurization of the box. Thick of the box as a tining fork. Hit it hard at the right frequency and you excite it. With different panels being different sizes it can actually have several different resonance points at once.

Sonic Barrier and Whispermat have no damping layer against the enclosure wall to dampen that resonance. The cabinet walls are still allowed to resonant independently of the barrier that is suspended on it.

The suspended barriers are typically just a sheet of vinyl too.

No Rez uses a heavy damper that is a asphalt composite that will deaden the box walls and eliminate the resonance. Its damping layer is nearly twice as thick as the one used on Blackhole 5. It is very effective and less expensive than Blackhole 5.

Excellent explanation, thank you! 

[Danny Richie]

You should publish that kind of stuff on your website, people like me would LOVE to read the results.

Yea, but the companies that participated in the tested would not like to share that info with other companies that they complete against.

How did the lead do?

It was the most bad ass stuff of everything tested. Mainly though because it had a damping layer that was over 1/8" thick. It then had a 1/4" thick foam layer, the lead layer, then 1.125" thick foam top layer. It also had a PSA on the back. This one even help shield the guts of the speaker from RFI.

But it was really expensive and there was a concern with handling and cutting the lead. Not that it will hurt you to handle the lead, but there is still a concern and a possible liability issue to deal with. 

It was really heavy too.

[Vapor Audio]

Here's the layout, the port will fit on the front but is it a bad idea to put it this close to the floor and bottom of the enclosure inside?  Should I rear port it?  What about down-firing port, how much space would it need from port opening?

Special thanks to my feline model for this photo session 





I can get some 1/32" lead sheeting fairly inexpensive.  When I do a from scratch cab build, I was going to try putting a layer of that inbetween sheets of MDF for all the walls. 

[SET Man]

Special thanks to my feline model for this photo session 

Hey!

     Cool! Nice kitty Yeah, Mr. Bubble my orange tabby cat helped me out too when I built my TQWT Fostex speaker back in 2002.

    Anyway, good luck with your project and keep us posted.

Take care,
Buddy

[Danny Richie]

I built a sub box one time that had a 3/4" MDF layer, a 3/4" layer of packed sand, and then a second 3/4" MDF layer. It turned out pretty rock solid and sounded very good. 

[Vapor Audio]

I built a sub box one time that had a 3/4" MDF layer, a 3/4" layer of packed sand, and then a second 3/4" MDF layer. It turned out pretty rock solid and sounded very good. 

That's great but what do you think about where I should put the port? 

If I put it in back it'll pretty much have to be behind a woofer, so I'm guessing I'd want to use a 90 angle on it.  Or I could bottom mount the port - I've heard you want floor clearance equaling the port diameter - which would be do-able.  I'm making a base for the cab out of 1 1/2" thick solid curly maple, and could cut out an hole in it right under hte ports.  Add in the floor spikes and it would be about 3" clearance. 

I'm having some trouble in Unibox.  For some reason it's just not modeling out anything like I'd expect, inputing 2 drivers in 1.3 cu/ft and a single 3" port ... I'm getting a peak around 68hz and F3 at like 52hz.  I know that can't be right.  Any input on how to tune that?  I could do dual 2" or 2 1/2" ports too. 

[Hank]

I'd put it in the back IF you will be able to have the cab at least 6" from the wall.  Hmmm...with the airflow involved here, I'd say 12" from the wall.  A port that large on the front will be an inviting curiosity not only for the cat, but for small children (yours or visitor's) to poke whatever (use your imagination here) in the port tube.  Marbles, anyone?

[Danny Richie]

For some reason it's just not modeling out anything like I'd expect, inputing 2 drivers in 1.3 cu/ft and a single 3" port ...

Bass box says that if you put a pair of the M-165X woofers in a 1.3 cubic foot box, then you'll need one 3" port that is 6.75" long to tune it to 38Hz and get a -3db down of 43Hz.

I'd run the port out the back. That will give you flexibility to vary the output with distance from the rear wall. It won't matter if it is behind a woofer.

[gprro]

why not go larger, like 2+ cu. ft.?

Slight off topic, sorry , how is Win ISD pro as a program, I have played around modeling the 130's and 165x. I liked the 165's in 1-1.4 cu.ft. at 29-32 hz depending on size

And, Danny, have you had time to test the moddified OB7 that Dayglow and i were interested in? I was hoping for a ported model with 165's. Dayglow said you were going to work on a sealed version? PM me a response if you want to. Thanks.

Turbo, good looking project, definatly keep us posted. Finished performance should be nice.

[Danny Richie]

Hey Turbo, I goofed. What I told you was optimal ported for a single woofer, not a pair.

No more air space than you have there for a pair of them I would go with a sealed box. You're really not going to get much more output or extension by porting that box.

And, Danny, have you had time to test the moddified OB7 that Dayglow and i were interested in? I was hoping for a ported model with 165's. Dayglow said you were going to work on a sealed version? PM me a response if you want to. Thanks.

I have not. The air space needed for four of them is going to start looking pretty large even sealed. You'd need a sub anyway so it might be best to use four M-130's. The box would be smaller and the sensitivity would match better too. Plus it is a done deal. That would be an OB-7 minus the 12" subs.

[Daygloworange]

And, Danny, have you had time to test the moddified OB7 that Dayglow and i were interested in? I was hoping for a ported model with 165's. Dayglow said you were going to work on a sealed version? PM me a response if you want to. Thanks.

gprro,

Sorry man, I forgot to follow up.....Yeah, I spoke to Danny about it, and it does look like the box is going to need to be very large. Disproportionately large. Not practical enough. Would have loved it though.

I will be building the OB/7 minus subs as my next main speakers, and will do some crazy overdone sub enclosure for my PR sub.

I'll update when I start building my OB/7's.

Cheers

[gprro]

ahh, oh well.

I was expecting to use about 4 cu. total. Definately big. Should have had extension into the 20's. The OB5 x-over looked like it may match up if the 200hz sensitivity was close. The woofer section would have to have a wider baffle 12 inches or more to not have the depth of the box be rediculously far.

I do have a couple of the original ascendant atlas 15's in the waiting, or maybe some diamond d915's.