Amp enclosure?

  • Thread starter Thread starter Izz
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Izz

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I am new to home recording and am looking for a way to mic an amp and get a dry clean signal, and also to be able to turn it up without disturbing neighbours.

I came accross these:

vocalbooth.com/products/ampbox_app.html

They cost about £900 so I was wondering if something similar can be done with a bit of DIY. I was wondering if anyone else tried doing it?

I was thinking of using thick MDF, then maybe lining it with three layers of plasterboard, and then some accoustic foam on the inside. One of the potential problems would be cooling. I use Peavey Classic 30 which is a tube amp. I think this case could get very hot over time and possibly damage the amp.

Any ideas much appreciated!
 
Izz said:
I am new to home recording and am looking for a way to mic an amp and get a dry clean signal, and also to be able to turn it up without disturbing neighbours.

I came accross these:

vocalbooth.com/products/ampbox_app.html

They cost about £900 so I was wondering if something similar can be done with a bit of DIY. I was wondering if anyone else tried doing it?

I was thinking of using thick MDF, then maybe lining it with three layers of plasterboard, and then some accoustic foam on the inside. One of the potential problems would be cooling. I use Peavey Classic 30 which is a tube amp. I think this case could get very hot over time and possibly damage the amp.

Any ideas much appreciated!
Click to expand...

Build an enclosure for a speaker, not the whole amp. You are correct in assuming that enclosing an amp in a small dead air space could overheat the amp.

I have seen plans for boxes like these. They have a mounting ring for a speaker, a mount for a mic, and connectors on the outside for the speaker input and the mic output.
 
Check out
http://www.homerecording.com/bbs/showthread.php?t=232207&highlight=iso+box

and
http://www.homerecording.com/bbs/showthread.php?t=224357

I've done a lot of thinking/work on this. I haven't rebuilt mine, the original still works well, but you can get great isolation and really nice sound from an iso box if you choose. I haven't played through anyting but speaker-in-box --> SM57 --> Mixer --> monitors in a long time. Best part is the wife doesn't yell at me for making noise anymore.

daav
 
Also maybe look into power attenuators for lower volume recording.
 
Tadpui said:
Also maybe look into power attenuators for lower volume recording.
Click to expand...

Those work OK, I guess, but part of a good fat distorted guitar signal is from a speaker straining to produce those high SPL's. Also, a power attenuator is a different kind of load on the power section of an amp than is a speaker; a speaker is constantly changing its impedance as its voice coil moves, where a power attenuator is a static load.
 
I have a question to those who have an isolation box: How loud is it outside the the box when driven? For example, how much leakage would a 100 or so watt speaker/amp set up register on an spl meter set 1 meter away? Thanks.
 
I guess really it depends on how the isolation chamber is made. There is really no way anybody here can give you an accurate measurement without knowing the exact specs of the isolation chamber, and even then it would be a stretch because of the room it is in, the flooring, etc.
 
Thurgood said:
I have a question to those who have an isolation box: How loud is it outside the the box when driven? For example, how much leakage would a 100 or so watt speaker/amp set up register on an spl meter set 1 meter away? Thanks.
Click to expand...

Mine is a box within a box holding a celestion vintage 30. If i crank my fender blues deluxe (40 tube watts i believe) on clean or OD channels, i can hear it in the room, and upstairs my wife can hear it but not enough to bother. At more reasonable volumes which are still quite loud, it is like someone is playing a radio a couple doors down, you can tell it is playing, but if you aren't listening for it, you would get used to it quickly.

My first run through on the iso box is heavy, but not really well built, the joints aren't sealed or exact, and the lids to both boxes are jsut sort of flat with no lip to sit in the box. There is no absorbtion inside.

If you had some skill, you could make a really quiet box.

Daav
 
Thanks for all the info guys!

I was really looking to make a box that would enable me to play in the middle of the night so I think the insulation is very important.

First, I thought I would make the box about 1m long. This would give me enough space for:

MDF (Medium Density Fibreboard) 25mm thick
+
Studio Spares Sound Stopper Acoustic Panels
+
75mm Studiofoam Pyramids
+
Peavey Classic 30 combo
+
about 12 inches to move Rode NT2a away from the speaker
+
a few inches behind the amp and behind the mic


I came across the Studio Spares Sound Stopper Acoustic Panels in their old catalogue (waiting for new one) so I am not sure if it is available. It is a polymer sheet sandwiched between two 6mm slices of high density foam. The density is 75kg/m3 and gives weighted transmitted noise reduction of 27dB. Not cheap- about £70+VAT for 2000mm x 1200mm x 14mm, weighs 16kg.

To insulate the floor of the box I thought of using Auralex Gramma Amp/Monitor Support (gearmusic.com/Acoustic_Treatment/Auralex_Acoustics/Auralex_Gramma_Amp--Monitor_Iso_Riser7.html)
(Maybe unnecessary?)

My concern then was amp overheating in the box. So I thought that a way around this would be to make a simple box to hold a Celestion 12" speaker and simply position this speaker cabinet on the floor of the box. One big advantage of this approach is that the amp stays outside for tone control, and another is- as i also have a bass guitar, I could have another speaker box for bass.

There two things I am not sure about-

How to do the cabling so I retain as much sound proofing as possible (I suppose 1/4" and XLR sockets on the outside of the amp would be perfect)

and most importantly-

what would be the best size (or ratio of sides) for the inside chamber?

Any thoughts?
 
What about using a lower watt Tube amp inside the iso-box. Like say 5 or 10 watters and crank it?

My 20 watter is way loud (as loud as a 1/2 stack). Not sure of the recording quality of those low watter, but maybe would help with the pure loudness of your recording session.

The only question would be would you still get the tone and distortion you need. I guess you'd have to find the right amp for your music.
 
What about the basic MDF box with fibreglass matting lining the inside? (You know, the attic ior loft insulation that's sold in rolls in your local B&Q).Apparently effective, and much cheaper than acoustic foam.
 
Izz said:
How to do the cabling so I retain as much sound proofing as possible (I suppose 1/4" and XLR sockets on the outside of the amp would be perfect)
Click to expand...

Not the most elegant or prettiest way, but the easiest and most leak-free way, would be to run cables through the smallest possible holes, heavily caulked, and install cable-mounted connectors on them.
 
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