Want to build an isolation cab. What should I NOT do?

Discussion in 'Gear & Equipment' started by SYLrules88, Sep 4, 2018.

  1. SYLrules88

    SYLrules88 I play drums!

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    I've got a pretty good idea of how I'm going to build it, unless there's a unanimous vote here to avoid something. It's got to fit my 2x12 Avatar cab in it standing on its side, and it's going to roughly be LxWxH 32x32x36. 1/2" thick plywood of the cheapest variety I can find (so far that's <$12 for a 4'x8'). Lining the insides will be Rockwool Mineral Wool 60, just a hair over $100 shipped from Amazon for 6-2'x4' sheets. Leaving it at just that, that's maybe $140-145 for materials. I'm about 50/50 on whether that will be enough to soak up all the sound waves. If needed, I could buy about 36 panels of some cheapo 1'x1' studio foam, but that seems to add another $50 so I'd almost like to try it without that first. I think me dimensions are big enough to allow an extra 1" of foam internally.

    I read another thread where a guy built one but the speaker cab was part of the structure instead of a box being built around an already existing speaker cabinet, and people complained of it sounding boomy. I figure if the cab is separate, I won't run that risk since I know what to expect from this cab and I know it isn't boomy.
     
  2. Randy

    Randy ROOMFORYOUROOMFORYOUROOMFORYOU Super Moderator

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    Separate cab from encloure won't stop it from being boomy. The sound waves create too much pressure and all the air stuck inside wreaks havok on the speaker and mic diaphragm; these are conditions that happen no matter what if you have that much energy being released in an enclosed space.

    The solution in both cases is finding some way to release the excess pressure without letting noise escape. Thats technically impossible but you can at least reduce it. Isolation cabinets like the Silent Sister are popular because they use a maze of wood inside with foam stuffed it strategically to get the noise to trap become trapped inside while the air can escape. I've got a Jet City cab I'm considering simulating this effect in using angled PVC tubes (similar to this concept: )

    As far as noise reduction, thin plywood and foam ain't gonna do it. Despite the insulation we're used to seeing in houses and recording studios, the best weapon for suppressing noise is thick and dense with some small gaps inside. Think, like, cinder blocks. And that's obviously impractical but one of the next best alternatives is sheetrock and if the box is going to be semi permanent, you could always line the inside of the a plywood box with matching dimensions of sheetrock and some insulation to control the acoustics inside the cabinet.
     
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  3. prlgmnr

    prlgmnr ...that kind of idea

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    Personally I'd buy some sort of reactive load box and use IRs rather than bother with an ISO cab.
     
  4. OliOliver

    OliOliver SS.org Regular

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    As someone who has owned an isocab fashioned from a custom made road trunk, and currently owns a Randall ISO412... You're right. Amps just sound best with a lot of room to breathe around them, even if that space is deadened. The air just has to go somewhere. Isocabs make that damn hard, and mic'ing an amp without an isocab is loud as shit. If you're recording at home, reactive load may be the best way to go. I like to mic my amps up, but with neighbours it's just not doable.

    That being said, years ago as an idiot teen, I flipped a lounge chair up against a cab to create a makeshift booth with the cushioning blocking most (if not all) reflections and it worked really well for the sound. The volume was only killed a bit, though. Big lounge chairs are a priceless studio commodity, haha
     
  5. tedtan

    tedtan SS.org Regular

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    This won't stop the boominess of an isocab. I would suggest you either 1) use a reactive load box with impulses if you need to keep the noise down, or 2) if keeping noise down isn't an issue, make yourself some gobos out of 6" OC 703 or equivalent and place them around your cab when recording. Option 2 won't kill the noise, but it will give you clean recordings without bad room tone, resonances, etc.
     
  6. NateFalcon

    NateFalcon #Ox45

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    Iso cabs are old tech, and are a compromise...at best. Use a load box and IR’s
     
  7. SYLrules88

    SYLrules88 I play drums!

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    I do actually want to mic a real amp so I'm going to stay away from IRs. Anything that I do modeling-wise I'll just use my 11R or maybe upgrade to AxeFx, but at the end of the day I'd like to be recording a real amp. That wood maze box with ports idea might be worth trying. I do live outside the city so bothering neighbors isn't the issue. I'd like to keep the in-house noise down for the girlfriend :french: and possibly still be able to record late at night if inspiration strikes without bothering her.
     
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  8. Kyle Jordan

    Kyle Jordan Ace of Knaves

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    How much room do you have to play with and where can you build? You'll want to think Iso Booth, not isocab honestly.

    Check out starting at 00:35 in the video.



    Do you have a small bathroom or a decent sized walk in closet? 20-40 square feet about. If you do, take a day and clear either out as best you can, line the walls with some blankets to absorb, and throw your cab in there with mics on it. You'll still have to watch for issues caused by the closed nature, but it should give you an idea of the sound. This is just a trial run that will allow you to check and make sure you like the tone before spending money.

    I know Henning Pauley had a video up showing his isoboxes and they are sizable, but more along what you're talking about. The one thing though is to kill sound, you need hard, dense materials. Here's a good article.

    https://www.acousticalsurfaces.com/...he-difference-between-blocking-and-absorbing/

    To block sound, especially for late night recording and harmonious relationship protection, you'll need something substantial even if you're amp isn't pushing the cab in the box/booth hard.

    Here's a tour of Tommy Lee's Atrium Studio. At 1:02:17, they begin to show the tiny room they stick cabs in. For your 2x12, You may be able to get away with half the floorspace and a shorter ceiling without boom and other issues.



    Finally, here's a video that shows the difference the load makes. It shows an amp run in to a DAW with a 4x12 NOT miked and only acting as the load, and two different load boxes. Starts around the 7:10 mark if the video doesn't start there.



    There's a difference between the cab and Two Notes load box, but it's small.

    This is a bit of an undertaking, but can definitely be done. You mentioned that neighbors aren't a problem, so that makes we want to ask if you think you could nab a small wooden shed, some Quietrock, and the insulation you already wanted and throw it up outside near your recording/playing room?
     
  9. Kyle Jordan

    Kyle Jordan Ace of Knaves

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    Found the Henning vid.

     
  10. SYLrules88

    SYLrules88 I play drums!

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    Thank you so much for that info!! I decided to abandon the idea of a cabinet and am instead going to turn the closet into an iso booth of sorts. If that still doesn't cut it, I could still try a small woodshed outside. There is room to do it. Thanks again for the videos. The Tim Pierce vid reminded me I need to upgrade my recording gear as well!
     
  11. prlgmnr

    prlgmnr ...that kind of idea

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    Tim Pierce's videos always remind me that I need to construct a fort out of amp heads and never, ever come out.
     

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