Building Isolation Cabinet

[jrod9900]

Hey guys,

I'm building an isolation cabinet for my 1x12 guitar cabs. I live in a condo and volume is a serious issue when using my Plexi, Rectifier, TSL, AC, and Tiny Terror. I also have a bad sounding room with way too much low end.

So, I've decided to build an isolation cabinet for my 1x12 cabs for recording electric guitars. I've read pretty much every thread and post I can on the internet regarding this topic. So I want to get anyone's input and thoughts. Maybe you can give me something I haven't found yet.

My cabinets are 24w x 20.5h x 11d. My isolation cab is going to be extra big to accomadate extra cabinets and extra room for the sound so it isn't quite as small.

The cabinet is going to be 36w x 48d x 36h. I am going to use 3/4" MDF board. I can't find anyone that has 1". I think I should be ok on that. I think I'm going to use Roxul Rockboard 60 4" to line the inside of the box to get maximum sound absorption. I'm also going to use some Auralex or similar 2" foam on top of the Rockboard to help with reflections inside the box. I will have extra room with these dimensions so I can angle it to help with standing reflections.

After accounting for the cabinet and all insulation and foarm, I should have over a foot in front of the cabinet to adjust mic placements, etc...

Does anyone have any thoughts or recommendations on this box? I think I could expect an SPL drop of 30-40db with this setup which will greatly help me in the condo and still be able to push the amps.

Any input is greatly appreciated. Let me know any tips if you have em!

Thanks,

JROD

[jrod9900]

Hope someone can help!

[M4-10]

Here's a link to the other thread.

A few points:

1) 3/4" MDF is easier to find, 40% cheaper, and easier to move around than 1" MDF, but will be a bit less effective as isolation on the low end.

2) The floor of my box rests on some cedar "feet" that were off cuts at the lumber store, to give some isolation from the floor.

3) The seal of the box is very important. I used latches to snug up the sides of the boxes.

4) A door handle bit for a drill is great to put a cable hole on the bottom piece of MDF.

My results were -32 dB for 1 KHz filtered pink noise and -20 dB for the low mids. Play some music loud in your DAW and then pull the fader down 20 dB to figure out what that means for isolation.

As far as the sound recorded within the box, I can't say for sure because I haven't tested it. I built my box for someone else and I don't really play electric guitar.

However:

A) The bigger the box, the less comb filtering, since reflected sound is diminished before returning to the mic.
B) The closer the mic is to the source, the less comb filtering, since the direct sound will be more predominant.
C) Insulation will cut down on comb filtering as well (in conjunction with box size), but is affected by the properties of the insulation (density and thickness). 3 inches of your favourite Rockwool should be enough to get most of the content of standard tuned electric guitars.
D) If the speaker cones are much closer to the bottom of the box than the top, consider putting the cab on something to raise it up.

If you get reflected sound at the mic down to an insignificant amount, the recorded sound in the box should be the same as the recorded sound outside the box.

[PaulP]

What do you guys do about heat buildup ? It seems to me if you're running tube amps it could get pretty hot in there. Too hot ?

[jrod9900]

Originally Posted by PaulP

What do you guys do about heat buildup ? It seems to me if you're running tube amps it could get pretty hot in there. Too hot ?

I'm not running amps in the box, just cabinets. I have heads that I will keep in my control room.

Don't think I would want an amp in the box unless it was a huge box.

JROD

[jrod9900]

Originally Posted by M4-10

Here's a link to the other thread.

A few points:

1) 3/4" MDF is easier to find, 40% cheaper, and easier to move around than 1" MDF, but will be a bit less effective as isolation on the low end.

2) The floor of my box rests on some cedar "feet" that were off cuts at the lumber store, to give some isolation from the floor.

3) The seal of the box is very important. I used latches to snug up the sides of the boxes.

4) A door handle bit for a drill is great to put a cable hole on the bottom piece of MDF.

My results were -32 dB for 1 KHz filtered pink noise and -20 dB for the low mids. Play some music loud in your DAW and then pull the fader down 20 dB to figure out what that means for isolation.

As far as the sound recorded within the box, I can't say for sure because I haven't tested it. I built my box for someone else and I don't really play electric guitar.

However:

A) The bigger the box, the less comb filtering, since reflected sound is diminished before returning to the mic.
B) The closer the mic is to the source, the less comb filtering, since the direct sound will be more predominant.
C) Insulation will cut down on comb filtering as well (in conjunction with box size), but is affected by the properties of the insulation (density and thickness). 3 inches of your favourite Rockwool should be enough to get most of the content of standard tuned electric guitars.
D) If the speaker cones are much closer to the bottom of the box than the top, consider putting the cab on something to raise it up.

If you get reflected sound at the mic down to an insignificant amount, the recorded sound in the box should be the same as the recorded sound outside the box.

20 dB will be a boat load better than what I have to deal with now. I also have a Hot Plate to help a bit.

I am thinking it will be a little better than expected due to the stats on the ROxul Rockboard 4" @ 100 or 125 Hz. It's pretty decent for the low end absorption compared to other stuff.

I will let you know how it turns out. I'll post some clips. Hopefully I will have it done in a week or two. I have to order the insulation. I'm getting the wood Thursday.

JROD