Isolation Cabinet Build

Discussion in 'Shock Brother's DIY Amps' started by itsGiusto, Feb 14, 2019.

  1. itsGiusto

    itsGiusto Tele-Meister

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    I would like to build an isolation cabinet. This would be a cabinet large enough to fit an entire speaker cabinet inside of it. I would build in ports on the side for running the speaker-signal from the amp in, and running two XLR mic cables out. The inside of the cab would have acoustic foam to dampen reflections inside the box.

    The purpose of this would be to record guitars at loud volumes to be able to capture the non-linearities of high-volume speakers, and to not destroy my own hearing, or bother my neighbors. I would add in ambience (room sound) later via room modelers or convolution.

    1. I'm considering a box-within-a-box approach, for added sound attenuation. One question I have, is would it be better to actually have an MDF box inside of another MDF box with an air-gap in between? Or would it be better to have some form of insulation in-between? Or would it be better to actually glue the inner box to the outer box with Green Glue? Which would provide the best sound attenuation?

    2. Is MDF the best thing to work with? Would it be better to actually try to use drywall or something else? Or would that be prohibitively heavy with no added benefit?

    3. How much room for acoustic foam should I leave in designing this? 2 inches on all sides? Is that enough?

    4. Should I do a different shape instead of a rectangle, to prevent standing waves? Or is the acoustic foam going to mostly deal with that anyway? If I did a different shape, what should should I do? Should I simply have a curved piece of foam on the mic-side? Should it be curved concave or convex relative to the mic?

    5. For the outside of both boxes, should I go with the "tennis ball riser approach", like this:
    [​IMG]
    Is this sturdy enough for long-term use?

    6. Is there some sort of metal or plastic panel I should use to mount the outer and inner XLR/speaker cable jacks on? Or should I just screw them directly into the MDF? Is there a particular way to route out space for them that minimizes sound transfer?

    7. Is there a particular method of connecting the MDF joints in creating the box that would minimize noise transfer? Any particular glue to use? Should I caulk it?

    8. I'm planning on using weather stripping on the lid of the boxes. I was going to go with the kind they use in car doors. Is that a good approach to create a tight seal? Should I have some sort of latch like this to help keep it tightly shut and minimize sound leak?
    https://www.surplussales.com/Images/Cabinets-Racks/Latches-Bolts/hwx-lch4.jpg
     
    Last edited: Feb 14, 2019
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  2. strat a various

    strat a various Friend of Leo's

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    I've helped to build several iso cabs. The most successful result I had in-studio was in an older building: put an amp in a coat closet full of coats, with a mic stand, and shut the door. But, anyway, my latest version is simply a closed-back speaker cab with the speaker mounted from the outside, and hinges installed to facilitate access to the mic mount. The speaker has an input-jack wire running out of the cab to the terminals, and the cab is it's own isolation box. Good results, surprisingly.

    I use the self sticking weather seal they sell at Home Depot ... for windows. It's white. I stick it to the box's edge that contacts the hinged back and put felt along the opposite sticky side. Seals good.

    A small closet works better, IMO. I know that doesn't help with neighbors.
     
  3. archtop_fjk

    archtop_fjk Tele-Holic

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    Interesting topic. I have a question though about the tone from an iso-cab.

    Suppose you wanted to gig a 30W amp head, and rather than using your trusty 1 x 12 cabinet (and damaging your hearing when you turn it up to 10) you use an iso-cab instead, with a mic (or two) fitted, running to your mixer board. Would this arrangement sound good? The reason I ask is that I'm using my Blues Cube Artist (80W combo) for gigging, and rather than turning up the master volume in the 40W mode, were running the signal from the line out to the mixer/PA. Since we now use IEMs, I can hear myself perfectly in the monitor mix but not blow out my eardrums (since I can control the volume, and can turn the master way down but still get a great signal from the pre-amp/EQ/reverb). It occurred to me that you could also place a mic in front of the amp then connect it to the mixer/PA and use the amp as normal (with the combo's 12 inch speaker), but then the sound level out front would be too loud unless I used the 0.5W mode (which I could). Anyhow, just interested if a head+iso-cab would also make a good gigging solution.
     
  4. flyswatter

    flyswatter Friend of Leo's

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    1. The box within a box makes sense if you were planning an ISO cab you could use with various pre-existing cabs. But I don't see the point of box within box if you're planning to build a dedicated cab to go inside -- when you could simply build one iso box for a speaker that will be half the weight and more airtight (since you can add jack plates and won't need ports to get the cables in and out)

    2. MDF can work but is heavy and you should wear a respirator to protect against the fine dust it creates when you mill it. Poplar or birch plywood would be my choices. Drywall won't work. It will simply crumble when you try any sort of joinery with it.

    3. Buy your foam product first then offset its thickness.

    4. Foam inside a rectangular cab should be alright -- as it is in any closed-back regular cab.

    5. (The pic won't load for me)

    6. Any stereo or electronics dealer that sells the stuff for car audio will have blank jack plates you can use for mounting different jacks. If you mount XLRs etc directly in MDF, any dampness or prolonged vibration will strip the screw holes and they will work loose.

    7. Dovetail or box joints add solidity, but if don't have the gear to do them, butt joints reinforced with dowling is plenty strong. Again, plywood will be easier than MDF. Regular carpenter's glue works fine if you clamp or nail while it sets.

    8. Latch the top or it is likely to rattle at whatever resonant frequency the cab has.
     
    Last edited: Feb 14, 2019
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  5. flyswatter

    flyswatter Friend of Leo's

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    It should work fine at gigs provided you have full control over your P.A. and monitoring setup. If you are frequently on gigs where you have to rely on a house system or whatever random sound guy shows up, you may have problems. One advantage of a live cab onstage is if the sound guy is one of those 'don't talk to me' types or doesn't know how to set up a good monitor mix, you can just set your own amp volume and survive the night.
     
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  6. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    here's the one I built, make sure you have a port in the box to allow for the compressions to disapate outward or you will roast your speaker , I put 2 X tunable ports on the bottom of the box and used sound insolation to create baffles in the lower box , there are 2 X 2" baffle ports between the upper box and the lower box I used a 100 watt Jenson 12 " inch speaker (8 OHM)

    On axis sennheiser E609 off axis Beyer dynamic ( both can take High SPLs )


    P1011343.JPG P1011344.JPG P1011346.JPG P1011350.JPG P1011347.JPG
     
    Last edited: Feb 14, 2019
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  7. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    1. I'm considering a box-within-a-box approach, for added sound attenuation. One question I have, is would it be better to actually have an MDF box inside of another MDF box with an air-gap in between? Or would it be better to have some form of insulation in-between? Or would it be better to actually glue the inner box to the outer box with Green Glue? Which would provide the best sound attenuation?

    I used a 5/8 ply in side of a 5/8 ply box, this is really heavey , MDF would be heavier

    2. Is MDF the best thing to work with? Would it be better to actually try to use drywall or something else? Or would that be prohibitively heavy with no added benefit?

    I would Use Ply , D grade cheap and easy to work with , I went to a fabric store and bought naugahyde to cover it with worked really well
    ( I used A grade finishing ply for the front , some scrap I had laying around)

    3. How much room for acoustic foam should I leave in designing this? 2 inches on all sides? Is that enough?

    I left 2.5 inches all around between the boxes for the sound proof insolation and used 2.5 inches of acoustic foam for the upper box, the bottom box has regular acoustic insolation lining the sides and pieces of staggered insolation to create the baffles to break up any standing waves

    4. Should I do a different shape instead of a rectangle, to prevent standing waves? Or is the acoustic foam going to mostly deal with that anyway? If I did a different shape, what should should I do? Should I simply have a curved piece of foam on the mic-side? Should it be curved concave or convex relative to the mic?

    the foam will take care of what you need for standing waves, the 2" baffles allow air to move from the upper box to the lower, the tunable ports in the bottom allow the air to move air compressions to between thew boxes to allow for hard useage with out burning up the speaker coil

    5. For the outside of both boxes, should I go with the "tennis ball riser approach", like this:
    https://photobucket.com/gallery/htt.../user/WildWes_2007/media/misc/riser5.jpg.html
    Is this sturdy enough for long-term use?

    6. Is there some sort of metal or plastic panel I should use to mount the outer and inner XLR/speaker cable jacks on? Or should I just screw them directly into the MDF? Is there a particular way to route out space for them that minimizes sound transfer?

    I made an aluminum , Jack plate , 2 mic return and one speaker send , XLR for the mics and 1/4" for the speaker send. Decoupling your box could
    be a good Idea, depending on where you place the box afterwards ( mine is in the garage and hard wired to my studio) I used sphynx glides and one handle and rear mounted wheels to be able to move it


    7. Is there a particular method of connecting the MDF joints in creating the box that would minimize noise transfer? Any particular glue to use? Should I caulk it?

    I used titebond worked fine , to fasten the sides of both boxes I used a ripped 2X4 into 3/4" triangular cleats , on all edges, glued and screwed

    8. I'm planning on using weather stripping on the lid of the boxes. I was going to go with the kind they use in car doors. Is that a good approach to create a tight seal? Should I have some sort of latch like this to help keep it tightly shut and minimize sound leak?
    https://www.surplussales.com/Images/Cabinets-Racks/Latches-Bolts/hwx-lch4.jpg

    what is missing from my photos is a 2.5" piece of the white foam ( like the type in the upper box) that sits between the upper doors this removes the vibration of the doors , I used butterfly latches that seal really tight , no insolation needed.

    Last edited: Today at 8:52 AM

    P1011348.JPG P1011349.JPG

    I hope this is usefull, also check out You tube there are some great Ideas on there , I got my Ideas from working with ZZtop and the commercial unit Billy G uses

    avoid boxes for the amp inside , the heat build up will be killer , Baffle ports and allowing the air to move freely are the most critical considerations if not done you will kill your speaker

    notice I've set up so I could remove the speaker by opening up the top box removing the latches and the speaker pops out , I did line the speaker hole with weather stripping to seat the speaker solidly, also make sure the speaker you choose can handle the amp , for me I have a 50 watt marshall JCM 800 and an 85 watt fender twin BFR, if you have mor questions PM me>
     
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  8. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    this vid explains alot about the tunable baffles and how I set mine up I used this vid as template while making mine

    have fun with it

     
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  9. flyswatter

    flyswatter Friend of Leo's

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    Nice work, 24track. I'm considering building one of these myself to sit in the shop, so your posts and pics are helpful.
     
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  10. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    Thank you,
    if you have any questions PM me .
     
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  11. itsGiusto

    itsGiusto Tele-Meister

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    Thanks for the great replies!
    I'm more interested in building a larger isolation cabinet, that I could put an entire speaker cab into, not one that's small and has only a single speaker mounted inside. The size of the largest cab I want to fit inside is roughly 2'x1'x2'. I'd also like the option of placing the mic a foot or so out, not necessarily having to have it right up against the grill cloth, so I was planning on making a cab to accommodate 2'x4'x2' of space, not including space for dampening foam.

    A few more questions:

    1. I was considering using Auralex 4" studiofoam wedges, though if there are cheaper-but-almost-as-effective solutions out there, I'd much rather go with them! Does anyone know any?

    2. Glancing around at a site like Auralex, it seems like they indicate that different products dampen different frequencies well. Is it better to have a variety of different foams on different surfaces, as opposed to one type? Should I also have bass traps in the corners?

    3. What should I use on the floor of the box to ensure no reflections are there? Should I just use more acoustic foam, or carpet or something else?

    4. @flyswatter and @24track, you both recommend using plywood, but isn't MDF much more absorptive? I don't trust plywood to actually get much sound reduction. I feel like with all the work I'll be putting into this cab, better to just wear a respirator and get better results. Although I might change my mind if MDF is prone to longer-term issues, like swelling, and thus not going to last. Is that the case?

    5. I'm not certain I understand the ports you're talking about. Wouldn't the existence of such ports allow sound to just totally leak out of the cabinet, effectively ruining isolation? It's hard for me to see/understand what's going on with that PVC piping and the labyrinth thing based on the pics in the video, so maybe I'm just not fully understanding?
    Also, would ports be necessary for my build, since I'm not planning on building a single mounted speaker, but instead a larger box in which I can fit an entire speaker cab? I've seen lots of builds on youtube where people are building larger isolation cabinets, and they don't seem to build in ports to relieve the pressure, but maybe I'm missing something?

    6. If I were to go for the double-box approach, are the boxes actually glued together? Or is there an air space, or some sort of insulation-space, for more sound separation? In my intuition, I feel like it'd reduce more volume if the inside box were not making physical contact with the outside box, so the sound would have to transfer from MDF to air to MDF again. Is that right? But maybe using something like Green Glue to actually glue the boxes together is a better approach?
     
    Last edited: Feb 16, 2019
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  12. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    my outside box is 4'X2'x2" the inner box is 1.5'X 1.5' X3.5' leaving room to place the bats of sound proof insolation to be fit in between them . my finished box measured out at about 150 lbs total. if your box is 2X2x1 and you use a 12"speaker you will not have room to mount the speaker

    Aualex foam is very expensive and for this purpose is overkill but functional a good foam shop will have what you need, I used sound proofing insolation I got from home depot, to insolate between the boxes and in the lower inside box

    MDF is really heavy and not that dense a matterial plus is prone to swelling if the cab gets wet and will chip readily if flexed, but a box is a box , and what ever works for you ,

    I based mine on the rivera Silent Sister design used by Billy G of ZZtop for their live shows, this vid explains the principle of the porting , by turning the PVC piping in the lower box I can effectivly reduce the amount of air leaving the inside box, there for allowing me to tune the port to allow for control of the venting, these boxes are deigned to reduce the external DB signal while allowing you to crank the amp to optimum level. but inherently do not allow for the speaker to create high levels of compression or sound pressure levels with out allowing the air to move out side the box in a confined area , the cone has to move both forwards and back wards effectivly creating a pump for the air in a confined area and if the air it pushes has no where to move to your voice coil will over heat and blow out the speaker in a very short time. not to mention that the diaphram of the mic will be pinned under pressure of the air compression.

    so yes the the air vents out side the box and by creating the sound baffles in the lower box I break up the sound before it leaves the inside box but allows the sound to dissapate before it leaves the box



    my inside box floats on a 2.5" piece of sound proof insolation in between the 2 boxes and is enough to suspend the inner box in place look at my 3rd & 4th pics see the acoustic insolation between the boxes there is no contact between the boxes, I intially over thought this as well and was going to suspend the inner box on springs , not neccessary , by any stretch

    take a serious look at the designs on youtube before you start , be aware of some of the pit falls in some of the DIY designs , like placing the amp in a box , etc , if going for a speaker in a confined area , allow for porting , between the upper and lower portions of the box ( I placed 2X2" round holes in the speaker mount plate to allow the air to move to the lower box) and investigate the external porting before you build , a little fore thought before you start will save a ton of headaches later .and if some one thought of it before youand worked out the issues , then find what works for you and dont over think it , its not rocket science, just basic physics.

    if you need more info Im glad to help!
     
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  13. noah330

    noah330 Friend of Leo's

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    Years ago I had a home studio with three iso chambers.

    At the end of the day it was a cool idea but I wouldn’t want it again.

    [​IMG]

    [​IMG]

    Matchless vs Line 6 for TGP that was about 20% correct.

    [​IMG]
     
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  14. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    cool design, but I bet they got hot, and look expensive , I could see a modified closet for this type of arrangement but i would be worried about heat buildup over multiple takes ( nice looking studio !, kudos)
     
  15. itsGiusto

    itsGiusto Tele-Meister

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    Thanks again, very useful info! I'll definitely check out the sound proofing isolation for sure!

    I still want to push back on the venting idea, however, in a couple of ways, to find out if it's needed or how to do it.

    1. In my post I was saying I wanted to leave 2'x4'x2' of clearance room, after considering the space that all the foam will take up. That means the cabinet I'm going to build will be significantly larger. I'm thinking of building a cab roughly the size of one of the small ones in this video:

    He doesn't have any venting or baffles in his, and he seems to know what he's doing.

    2. Could you provide any cross-section diagrams that show how the baffles and pvc and labyrinth fit into your box? I'm not understanding how they're all oriented inside, but I feel like I could get it with a quick sketch showing two separate cross sections, and how everything fits in the space.
     
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  16. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    just remember that the speaker forward motion is pumping air into a closed area and if the air cant move ( same with the rear of the cab) you will over heat the voice coil in the speaker and it could damage the speaker even if it is a high powered speaker over prolonged useage in a session , all closed back cabnets are ported to the front of the cab to allow air to escape from rear compressions. I watched above cab design when i went with the design I came up with ( that, and I really liked Billy Gibons set up and seeing up close and personal motivated me , because its used night after night with out issues.

    P1011632.JPG


    this is really rough but to give you the quick view of the lower box ,

    Scan 1.jpeg
     
    Last edited: Feb 16, 2019
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  17. itsGiusto

    itsGiusto Tele-Meister

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    But I guess I'm trying to draw a distinction between the type of isocab you made and the kind I want to make. I think they're significantly different, in that yours had the speaker mounted directly to the cab, between two sub sections. You definitely needed porting in there, especially between the front and back, to allow the air to circulate to the back to speaker when the speaker pushes forward.

    For the kind I want to make, there should already be free air flow around the sides of whatever cabinet I'm putting inside (remember, I'm planning on having this be a full enclosure, in which I'm putting smaller guitar speaker cabs. I'm not mounting a speaker directly inside like you did). In this situation, is it actually necessary to have porting from the inside of the cab to the outside? I see lots of builds of these like I'm planning to make, and no one seems to be porting from the inside to the outside.

    Also, it's not making sense to me how the porting/labyrinth system works and fits in your cab, so I think some diagrams could really help.
     
    Last edited: Feb 16, 2019
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  18. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    I added some
     
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  19. 24 track

    24 track Doctor of Teleocity Silver Supporter

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    now given you have decided to use an exsisting spker cab in a box ( I take it no amp inside ) the speaker cab will be ported so the sound inside the cab will have a place to escape now this just leaves the external porting to release the sound pressure levels and if you placed a tunable port ( one you can adjust how much SPL escapes ) behind the speaker cab you may be good to go, just place a heavey blanket ( moving blanket ) on the box over the ports to deaden the sound and that may work for you, depending on how powerful your amp is a cranked 100 watt marshall is going to produce a ton of SPLs conversly a 85 watt Fender twin will as well thats what i use

    Most manufacturers of professional iso boxes give a reduced level of so Many DBs like minus 30 DB but never a 0 db out side the box
     
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  20. itsGiusto

    itsGiusto Tele-Meister

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    Thanks, the diagram is very helpful, and far more neat and detailed than I needed! I understand more what the PVC pipe is doing, and how you can "tune" it.

    In your diagram, let's call the vertical axis the "height" and the horizontal axis the "width". That means that the axis going into and out of the page would be the "depth".
    Does the baffle labyrinth extend all the way along the depth of the box? Or does it only cover a portion of the depth? In the video you posted earlier, it looked like the baffle labyrinth was only a small portion of the depth.
     
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