Building an Isolation Box
Old 29th April 2009
  #31
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2x12 box
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Old 29th April 2009
  #32
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Quote:
Originally Posted by effectsnut View Post
Well Mr Zipps, Its not a rocket science. I wanted to fit a 4x12 cab so I measure the cab. I want to add 2 inches per side for sound proofing or damping I should say. then another inch per side for clearance. Then your cab thickness and maybe 2 FT for Mic's.. I put some small pieces of wood as stops to hold it from falling in then clamp it where needed...One thing you don't want to use is the glue spray to hold the sound proofing. Use a staple gun
Cheers for that. I've been looking into the materials. I'm not building one for a 4x12. I'm going to be using modest combos - 15w Fender Bass and 30w Marshall. Therefore, I'll go for around 2ftx3ft lining it with the foam pictured below, also incorporating (for the base) a small tennis ball riser similar to the one pictured that I built for my vdrums kit.







Thanks effects nut.

Zipps
Old 29th April 2009
  #33
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I like the tennis bass effect...I put my cabs on top of 4 inch foam myself
Old 4th May 2009
  #34
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Door

How do you get the door not leak?
Old 4th May 2009
  #35
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idk where we left off, but to the OP:

make walls out of roxul rockwool with 2x4s for the frame. i would go at least 4 inches thick, 8" if you can budget it right. that will not only isolate the cab, but keep it quiet outside. i would avoid enclosing the space with any sort rigid material that would reflect the sound waves. that will enduce phase cancellation tutt also avoid aurelex and of those around the house items, i.e rugs, old beds, etc. yes, they absorb well, but not all frequencies. this will leave you with mud. you need to get acoustic insulation to get real results. dont half ass, it isnt worth it
Old 4th May 2009
  #36
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Quote:
Originally Posted by mikethedrummer View Post
idk where we left off, but to the OP:

make walls out of roxul rockwool with 2x4s for the frame. i would go at least 4 inches thick, 8" if you can budget it right. that will not only isolate the cab, but keep it quiet outside. i would avoid enclosing the space with any sort rigid material that would reflect the sound waves. that will enduce phase cancellation tutt also avoid aurelex and of those around the house items, i.e rugs, old beds, etc. yes, they absorb well, but not all frequencies. this will leave you with mud. you need to get acoustic insulation to get real results. dont half ass, it isnt worth it
Hi Mike

Are you suggesting not using wood or rigid material as a means of enclosing an isobox at all and having an isobox just consisting of 4"-8" thick of rockwool? Also, are you suggesting that sound could penetrate through acoustic material and reflect back once it hits a rigid surface if enclosed with one?

Just requiring a bit of clarity before I plan stuff as I'm new to acoustics.


Thanks

Zipps
Old 4th May 2009
  #37
There seems to be a logical flaw in his argument. If that would prevent sound from coming out, then the sound would have never reached the exterior walls in order to be reflected back so it wouldn't matter if it had walls or not. If any sound would have reached the external solid walls then it would be sound that wouldn't be kepted inside and therefore wouldn't be isolated.
Old 5th May 2009
  #38
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Quote:
Originally Posted by Dean Roddey View Post
There seems to be a logical flaw in his argument. If that would prevent sound from coming out, then the sound would have never reached the exterior walls in order to be reflected back so it wouldn't matter if it had walls or not. If any sound would have reached the external solid walls then it would be sound that wouldn't be kepted inside and therefore wouldn't be isolated.
By the definition of the word isolate you are correct, but now were arguing semantics.
If he was using a 15 watt crate amp that cost $100 I would agree with you completely. 8" of even the most rigid rockwool wont stop the noise of a 4x12 with a powerful head cranked to the point where the cabinet is reacting harmonically with the tone. Though, due to the reflection the total distance the sound would have to travel would be 16". That might be enough to completely stop all tones, but is it really worth risking when it being absolutely "isolated" isnt necessary?
Plus, depending on the construction, the box can be taken apart and used as bass traps when not in use. Moveable acoustic walls are my new favorite studio toy =] Drum iso, vocal booth, etc.
So OP, to answer your questions, yes and yes. I can stand on the opposite side of my 4" walls while drums are being played at full volume and hold a conversation at normal talking volume. 8" would be killer. thumbsup
Old 2nd August 2009
  #39
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Kenny
Did you ever build these? I am looking to do the same very shortly and wanted to know how it worked out for you.

Thanks!
Old 2nd August 2009
  #40
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Thread Starter
There was a slight change in plans although I will be building these (in a different location) over the next few months.

I will report back.
Old 2nd August 2009
  #41
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Yes, "slight" change.
Old 2nd August 2009
  #42
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I encased an Alnico 8 inch 15w max spkr in a small cab and placed it in a 2X4 ft plywood cabinet with 2 inch 703 all the way around.It is fed with small watt boutique amps and cuts the noise from 120db to 70db.Try every mic you got with placement attempts just like in a room.You'll find something that works! I also have had luck with another spkr/cab placed facing opposite,wired out of phase,with an R121 or R84 centered and even fed by two different amps.It's fun to blend them.
Old 2nd August 2009
  #43
3 + infractions, forum membership suspended.
Quote:
Originally Posted by juniorhifikit View Post
You know...

I built one - kind of an enlarged booth. It did it's job, but also sounded kind of funny. You'd think a 57 stuffed right up against the grill cloth of a Marshall wouldn't hear any of the walls. But it did. And the amp sounded "suffocated". I ended up pulling the amps into the control room and tracking with headphones. Amps need to breath I guess.

Any time I'm forced to use a doghouse for amps, like for isolation when tracking live, I usually try to take a direct feed to re-amp later.

Is this for band isolation, or don't annoy the neighbors isolation?
This is exactly the point I was about to make. Generally iso boxes don't work well with big cabinets. Big cabinets move a lot of air and they need a certain omount of volume of air to operate properly, otherwise the sound wave can't "form" and you lose the very characteristics that you were using the big cabinet to achieve. Even a small iso booth is generally too small to get really decent sound off a 4X12.

This being said, if you really want to try this and you need to contain the sound of a cranked 4X12 there is only one way to do it - LOTS OF MASS! The only way to contain that much energy is to have an enclosure that is too heavy to be vibrated by that much power. That means that rock wool, acoustic foam, or an air gap aren't going to cut it. You need something like granite, lead, of many, many alternating layers of drywall and something like Aurelex Sheetblock, with a few layers of particle board thrown in for good measure. You also have to effectively isolate it from the floor with something like Sorbothane.

Understand that for this thing to be effective it WILL NOT be portable - or most likely even movable without a forklift.
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