Amp isolation box

[rcole_sooner]

This was requested a while back, and another post reminded me to post it.

This is a very simple drawing of the dimensions of a amp isolation box that I built. I will say that this thing is huge.

To build the box I did this:

1. build the inner box from 3/4" MDF
2. build bottom and 2 sides of the outer box from 3/4" plywood.
3. add corner and side bracing.
4. line the outer box with fiberglass insulation bats, double on bottom.
5. set the inner box in the outer box.
6. cover the inner box with more insulation.
7. complete the outside box around the inner box and insulation
8. add bracing

Now the fun part...

9. cut the top off the box, about 12", with a table saw

That was really not any fun at all.

10. carefully remove the top and don't let the inner lid fall out.
11. drill 1" holes in the top of the inner box.
12. use straps and screws to attach the inner lid to the outer lid.
13. attach the lid with some bog ol' hinges
14. add large casters, handles, and latches
15. drill holes for mic, instrument and power cables.
16. install cables and plates
17. use insulation to fill around the cables
18. finish as desired.

 

[Wally]

This is not a box into which I would place a tube amp because of the lack of heat dissipation. Most folks who want to isolate the sound of an amp use an isolation box that houses just a speaker and a mic instead of the whole amp, or if they want to isolate a certain amp/speaker combination, they use a room....which can allow the heat of the amp to dissipate. A speaker isolation box would be smaller and less complicated, too, right?
IF I am confused on the application here, I apologize for the interruption.

 

[rcole_sooner]

Quite alright. I built and use an isolation box with just a speaker in it, as in the pic below. This thread is indeed for an amp isolation box. We thought about ways to add fans, and there are a few simple to very complex baffled airway approaches. But my friend, who uses this box, thought it would be okay without any heat dissipation. He plays in a Church and only runs the amp about 2hours at a time. I built two of these for his Church band, and they have been using them without any heat problems. But heat dissipation could be added.

This is a pic of my speaker only isolation box, the basic construction is the same:

Edit: Oh, yeah, the speaker iso box above, does not have a lid for the inner box. I'm only running a 5w amp and this works fine.

 

[Gabriel_GR]

OP, I am looking to build something exactly like this.

What are the dimensions of your box? And how quiet is it? I only have a 10Watt combo and I was thinking of making an ISO box with a 10" or 8" speaker and a mic so that I can play at night with natural tube sound and headphones and at the same time record my ideas without caring about the time. If my amp was at a bedroom level originally, will the box be almost silent with the same amount of volume?

Also, what was the total cost sans mic and speaker.

Thanks in advance.

Edit. I just saw the dimensions in the blueprint.

Do you think that I could get enough "attenuation" with a 25"x25"x 30" single panel mdf box

 

[rcole_sooner]

The blueprint is for a huge amp isolation box I built for a friend. It is a beast. The speaker iso cab is much smaller, but the same idea.

The speaker cab above is 19.5"wx18d"x31"h. It has a 12" speaker in the inner box and fiberglass insulation between the 2 boxes. I stuffed some filter material around the top to keep the fiberglass out of the way.

I play my Peavey Royal 8 5w at 5 gain, 4 tone, and 4.5 volume. I listen through my PC speakers at about normal TV program volume. Most folks don't even know the speaker cab is in the closet unless I turn off the PC speakers. My wife and son watch TV and we don't even close doors. My son is across the hall, my wife is downstairs.

 

[rcole_sooner]

I'm pretty embarassed at my playing in the video, and the general quality of it. I need a better video setup, and that is on my list of stuff to do. It will give an idea of the sound isolation capabilities of this cabinet. ...Man, I played the riff backwards, I was so nervous...

 

[rcole_sooner]

...Do you think that I could get enough "attenuation" with a 25"x25"x 30" single panel mdf box

You might get some, but the double box, fiberglass, and wheels (separate the box from the floor), is what does the trick. You have to convert the sound waves into heat or energy or something like that, and that is what the various spaces, walls, and materials do. Fiberglass is really good at insluating.

You can tell by this description that I am not an audio engineer or have any real knowlege about the science. But I did stay in a Holiday Inn last night, not really, but I did read a lot about it.

 

[rcole_sooner]

Also, what was the total cost sans mic and speaker.

My best guess

MDF - $45
Fiberglass - $20
Wheels $10
Hinges - $10
Nails - $5
Screws - $5
Glue - $5
caulk - $5
Paint - $20
Handles - $20
latch - $10
Jacks (mic and speaker) - $10
wire (mic and speaker) - $10
Speaker - $50
Mic - (??? maybe $50)
Mic flex mount (??? maybe $20)

Total - $290 (if my math and guesses are right)

Road case hardware is expensive and really is what adds the most to the cost. Well, other than the speaker and mic and lumber, oh nevermind, stuff is expensive. Makes one appreciate how some companies can offer the prices they do.

 

[Gabriel_GR]

Thanks a lot for the feedback.

19.5 X15 x 31 is not too bad. I guess going with a 10" greenback instead I could save 2 inches at every dimension of the base. It could double as my laptop table too

I was thinking about using spikes to decouple the unit from the floor as I won't be moving it but maybe spikes on a selve that sits on wheels is even better.

I am a bit concerned about fiberglass because I really don't want to breath that stuff and it will be in my bedroom so I might look in a different kind of absorption material for the space between the mdf.