Building a Iso Cab

StayTrue

Member
Aug 17, 2011
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Boulder, Colorado
So I've decided I am going to build a Iso cab for my 4x12 Mesa. With living in an apartment, it has become really hard to record efficiently at the cost of pissing my neighbors off. I can't really convert a closet into an iso room without completely destroying the apartment walls. I plan to build it over Memorial Day weekend, so all I'm waiting for is the supplies to come in.

I plan to take a different approach than most people seem to take when building their own Iso cab. The main sound proofing material I plan to use is called Acoustiblok. Here is a video of how it work:



Here is a link to the specs on the actually product I will be using:

http://dl.dropbox.com/u/39522476/AB32 Cutsheet 04292011.pdf

The walls of the box will be roughly 4 layers thick, using the Acoustiblok, birch plywood, and one other layer of a sound absorption material. The inside of the box will be treated with Auralex foam to limit reflections. Also, I plan to place the cab on a Auralex Great Gramma to uncouple the cab from the walls of the Iso cab.

This is where you guys come in.....

I plan to make the box collapsible. The box will be a little over 3'x3'x3', so it will take up some space. With making it collapsible, I can store it under a bed when it is not in use. I plan to initially seal the box with acoustic sealant, but then cut them with a razor blade. The walls with either be screwed together or bolted, which ever seems reasonable after I start to build it. Do you think the sound loss through the seems will be substantial?

Something else I have considered is venting the box, much like the Rivera Silent Sister. I could use vents to allow the cab/mic to breathe with the outside room. However going back to making it collapsible, it the seams allow the same effect, the vent will be pointless. I also plan to cut a port for the cables to go through the wall.

Any other suggestions you guys may have are more than welcome. I really think this will work very well, or it may be a very expensive construction project.......
 
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4 layers should significantly decrease the outside volume. If you vent the box, it's going to let a lot of noise get out and almost defeat the purpose.

Personally I would rather record with a 4x12 in a room at low volume but to each his own.
 
Can't really see the advantages of an iso box over a dummy load + impulses. It's always going to deteriorate the sound coming out of the speaker no matter what.
 
I builded something like this a year ago, although i used rather cheap materials, all together it costed me like 150 euro. Just large enough to fit a harley benton 2x12 in it. It isolates the mid and hightones rahter well, but it seems the lows get amplified in there. You notice it best when standing at least 4 meters away from it. Ofc the stuff i used totally not comparable what you are planning to use.

http://dl.dropbox.com/u/1283560/SANY0700.JPG


some stuff i recorded in there, basicly almost everything i ever posted here was done in there.
http://dl.dropbox.com/u/1283560/SANY0667.AVI
http://dl.dropbox.com/u/1283560/Narco.mp3
http://dl.dropbox.com/u/1283560/LandM.mp3
http://dl.dropbox.com/u/1283560/Tbdm.mp3
 
If you make something like that, you have to be very careful as the wrong design could ruin your tone horribly. You will need absorbing and diffusion on the surface parallel to the speaker, and even with that, the surface should not be truly parallel.
 
Tried that (building my own iso cab). The sound is not good. All sorts of acoustical issues. Imagine 412 cab cranked in small box. Also, it doesn't help so much to lower the general loudness "impact" of the cab. I'm talking about low frequencies. Sometimes cab resonates and makes things even worse.he best way to prevent sound leaking is to have sealed iso cab. Or iso cab inside the iso cab.But that means not much of air movement inside the cab. Which means, bad sound. Then you have to deal with absorption or even diffusion treatment inside the cab.
I also never heard any good clip with commercial iso cabs.

Try playing at lower volume but put some heavy absorption panels around the cab, in the right places to pick up the reflections. Not too close to the cab. Lift the cab from floor if you live in apartment.
But what I really sugest is using impulses.
Few years ago I tried some impulses+amp and I was never impressed. I kept using amp simulations and hardware processors.

Till week ago, I tried miking my new amp-cab setup. But had no luck (I changed mikes, thought something was wrong with my 57, changed guitars, but now i think that the main reason for not pleasant scooped sound was the cab, although it had v30 in it).
Then I threw the di box into signal chain between cabinet and amp.
So, the next thing was to get some GOOD "flat poweramp" impulses because I used my amp pre and poweramp. Same amp settings. Cranked amp.
I cannot describe you the thrill with the results.
THE SOUND was there. I completely fell in love with this technique.
Currently I don't even think about using processors or vst simulations, or miking the cab (though I am planing to buy mesa oversized for recording and try that setup).
At the end of the day, things like kemper and axe use impulses also . And they all sound "real". I was even thinking about buying kemper or axe, but now I don't really feel the need for that stuff. It feels nice to buy real amps and just use speaker simulations.

Also, I really dig stuff like torpedo's speaker distortion.

So my point is, with the impulses being so good these days, don't even bother with building iso cab.
Just get dummy load or some cheap speakers to take the load from the amp (without wooden cabinet) or throw blankets or something over your cab and send your poweramp signal with di to your computer.
You can send preamp out signal only, but I was never impressed with that sound vs. poweramp out.

Also, keep in mind that big iso cab is really big. It takes much more space in room than 412 cab. It's like a big wooden box.


P.S.

That youtube video shows how to decrease the noise, but doesn't show you the sound inside. And that's your main problem, the sound inside iso cab. It's not so hard to lower the sound of your amp, the hardest thing is to make it sound good inside the iso cab.
 
I builded something like this a year ago, although i used rather cheap materials, all together it costed me like 150 euro. Just large enough to fit a harley benton 2x12 in it. It isolates the mid and hightones rahter well, but it seems the lows get amplified in there. You notice it best when standing at least 4 meters away from it. Ofc the stuff i used totally not comparable what you are planning to use.

http://dl.dropbox.com/u/1283560/SANY0700.JPG


some stuff i recorded in there, basicly almost everything i ever posted here was done in there.
http://dl.dropbox.com/u/1283560/SANY0667.AVI
http://dl.dropbox.com/u/1283560/Narco.mp3
http://dl.dropbox.com/u/1283560/LandM.mp3
http://dl.dropbox.com/u/1283560/Tbdm.mp3
I think the low end will be fine from outside the box. If I decouple the cab using the GRAMMA and use Acoustiblok, it should suit it's purpose. I also plan to use a sound reduction pad that is used under laminate flooring called Quietwalk. It's thinner than the carpet pad you used and made specifically for reducing transfer of noise through the sub floor.
 
If you make something like that, you have to be very careful as the wrong design could ruin your tone horribly. You will need absorbing and diffusion on the surface parallel to the speaker, and even with that, the surface should not be truly parallel.
I've given this a lot of consideration. I'm trying to figure out a way I can taper the box from the cab to the far wall. That way, the walls will not be parallel. I've also wondering if I make the walls angled and treat them with studio foam, will I really need to use diffusers? I hope the angles walls on the inside will reduce the standing waves enough.
 
I also plan to use a sound reduction pad that is used under laminate flooring called Quietwalk. It's thinner than the carpet pad you used and made specifically for reducing transfer of noise through the sub floor

hate to say it man, but i don't think that stuff's gonna help much

honestly, i can't help but to be pessimistic that your iso cab will give you the results you're looking for, but the best of luck to you with it regardless!
 
My advice would be to get something like this:

http://www.palmergear.com/pga04.shtml

I own one of this particular model and can tell you that you'll get a much better tone out of it than you will out of any cab iso box. You'll get the sound of your tube amp without the muddiness and boxiness of an cab iso box. Maybe it won't sound 100% "authentic" to the sound of a real rectifier cab, but if you put your cab in an iso box, you won't have an "authentic" sound either.