Guitar cab insulation box

Hi !

So, the problem is that when recording “louder” rock music with all tube amplifier head certain volume is needed to get nice poweramp distortion. Nowadays there are loads of small wattage amplifiers for that purpose but even small 3-5 W all tube heads are way too loud to play in detatched house. Power soaks do work but they are doing nasty things for midrange. And are friggin’ $$$$. And as majority of small tube heads do not have master volume (like they should not :wink: ) the only way to record guitar is to make an insulation booth / box.

So I built one…

I have 5 W all tube head with a matching 1*12" cab. I placed a mic front of it, measured minimum inner dimensions for a box accomodating mic and cab and added roughly 2 1/2 inch to all sides . Then I bought 18mm birch plywood and made a box using just screws and silicone in every seam to make it air tight. Loads of silicone that was. Then I put two layers of densiest butyl sheets I could find to all inner walls, installed a threaded bar matching mic clamp threads as a mic stand to the bottom of the box and finished the box interiours with foam to tame flutter echo / boxyness. Lid is fastened with eccentric latches and there’s 3 mm window seal betwen the box and the lid. Installed 1/4 neutrick female plug and Neutrick male XLR connector to the back wall and soldered cables to cab and to the mic.

Results…I can crank up the amplifier to full volume and disguss at the normal voice with another person present at the room whilst playing. Huge drop in sound pressure level, something I never dreamed of. I can now use 58 or 57 to record my guitar…with preamp distortion…as raw as I want it…instant old Judas Priest :slight_smile:

Recorded guitar sound does not have any signs of boxyness. Only downside is that some of the microphones I tried were not able to handle the sound pressure level inside the box and delivered fairly “congested” sound but all-rounder dynamic mics do deliver the goods.

Happy Chappy :wink:

Now I can dive into tube market to find tubes with the “right” sound for my liking…and I do not need compressor for guitars anymore as powertube is taking care of that :wink:

Just wanted to share this and encourage everyone with similar DIY project in planning state to materialize it…



I’d like to do something similar … but more along the lines of a 300,000 cubic foot soundproofed room. That would enable a great deal of mic placement experimentation. :wink:

(originally wrote “square” feet … but I meant cubic feet … it makes a difference :wink: )

…I was first thinking about doing something for my Marshall stack but the budget estimate was too high :slight_smile:


We want photos :mrgreen:

Will post shortly…btw…no paint or varnish on the box…raw…will put some audio samples a well :slight_smile:


Most excellent, I love the smell of DIY in the morning (or any other time come to think of it) :smiley:

Very cool. I have covered my amp with pillows and put the whole thing in a closet to attempt to do similar. I need to go as far as you have to get it right though, because sometimes it’s boxy. And it’s a real pain to set it all up and then decide you need to turn the tone knobs a little! Do you have any issue with heat buildup inside there?

Only cab is inside and head outside the box so box does not play a role in heat build-up. Obviously tubes are hotter than ever :smiling_imp:

Thus the access to knobs is not limited either.

This little thingy helps in other situations as well : when playing or live I can have another cab as a monitor and guitar is miced from the box -> no leackage from other instruments into guitar channel. And when tracking live there’s no leackage from the box to drum overheads.


Oh, right, you said that already, should have read more carefully.

I once built a nice box inside a box and stuffed it a way in a wardrobe. Kinda almost silent outside and it worked very well for recording into my Tascam PortaOne (Yes … THAT long ago!). Then I accidentally pulled the speaker cable a little too hard and fried the Marshall 5210 50w amp!!! Yep, I let the magic smoke out … :astonished: :open_mouth: :blush: :frowning: :frowning: :frowning:

Anybody who’d be able to make an guesstimazation for a repair cost? IIRC I think the transformer and power transistors looked “funny” so maybe I did a too good job trying to kill my darling? :cry:

damn, that was dumb! :imp:

built one for myself.
pics on
have a cab with a 400W black mesa EV in it and it sounds G R E A T.

Can you link straight to the photo? It just took me about five minutes to figure out where it was. I found it, though. Looks nice. :sunglasses:

Also, your avatar isn’t being displayed. Maybe not within the proper requirements? :confused:

I’ve always wanted to build an ISO box, and can do it… the only problem I have is space to keep the thing. I’ve pretty much run out of space for any additional large box to sit having all the gear I have - including an electronic kit.

What I’ve been doing with wonderful results is recording the line out of my Mesa Triple Rec and simply using a cab sim in Guitar Rig. It sounds amazing, no one has ever noticed yet that it’s not a mic’d amp. Been curious about the amp/cab sims in Cubase 6, think I’m going to try that this morning.


I tried the VST Amp Rack today and was so impressed I had to post about it:

I’ll say, I’ve loved simply using my Mesa head and cab sim, it really eliminates the annoyance of micing a cab. That, and the even bigger annoyance of getting the exact same mic placement for recording different parts over an extended period of time as the slightest bit of difference in mic placement changes the sound.

The thing though, is even using my head with a cab sim requires me to turn up the head pretty loud for a decent sound and recording signal which is often inconvenient especially at night. So, I’ve always desired a full on amp/cab sim and now I can do that. I have to admit I am psyched at the sound of Steiny’s amp plugin system!


I always take several photos of the mic placement for future reference, also of the amp settings and placement. even then things can sound different.

But I do like micing cabs.