Sound Isolation Cabinets for Guitar Amps?

[gafftaper]

I'm working on controlling stage noise at a church. The debate has come up over putting the guitar amps off stage in a closet and micing them vs building mdf cabinets, with acoustic foam inside, hanging a Sennheiser E906 on the front and shoving the amp in the cabinet.

I've heard that isolation cabinets can create bad phase issues and comb filtering problems. Is this true? Are there ways to build the cabinet to avoid this problem? Been doing some searching on youtube and other places and it looks like everyone is firing the amp into a curved surface. Does this stop the phase issues?

What about heat? The guitar player wants to build sleek little cabinets with just a few inches of clearance all the way around. From what I am seeing this sounds like a recipe to cook an amplifier.

 

[StradivariusBone]

As to the heat issue, the best solutions I've seen are to have a separate head and then port your wiring through the box for the speaker cabinet inside. That way the guitarist will be able to goof off with his or her tone (which after working with church musicians for any length of time I'm convinced it is some type of repetitive motion disorder). The combo amps I've seen in action have a lot of heat to dissipate and I've seen some with baffled fans. You will need an intake of some sort to cycle air through and any opening is going to let the noise back out.

I haven't seen the curved surface design, mostly the boxes built out of MDF and lined with acoustic foam. I would wager some type of diffuser panel would help and I've seen quite a few with the spiky acoustic foam in use. Anything that would disrupt the flat surface I'm guessing is the goal there.

Our solution was to put our amps in a backstage hallway. It's big enough for the sound to move around, but isolated enough to help with the mix. Plus it's air conditioned.

The guitarists in our church disliked it at first, but making that transition and also to IEM's reduced our stage volume. Now if we could just get the drummer to play softer....

 

[Footer]

Its not cheap, but the real solution is something like this: http://www.sweetwater.com/store/det...TwSvspCXdwy9W_WVR5C-TJzI4J09rllAPgaArv58P8HAQ

Other options are point the amp upstage, put it in a wing, or put it in front of the person as a second wedge. I've never liked the sound of the full enclosure. The amp isn't designed for that nor is the mic you are using.

If its tone they are wanting when cranked to 11, then you need something like the load box I linked to. Many artist carry them these days and they do work. You get the tone of the amp running at 11 when it is only putting out 3.

 

[FMEng]

Here is a pretty good article about amp boxes.
http://www.churchsoundcheck.com/isolating-the-guitar-amp.html

I have a partial solution that helps. Onstage makes some amp stands that allow the amp to be placed like a monitor speaker, with it pointing right at the guitarist's head. They tend to lower the volume quite a bit with it positioned that way.

 

[Blassiter]

I recently built a heavy duty iso cabinet without soundfoam for my Bandmate's recording studio, I didn't use any curved angles, instead I varied my layered insulating materials and left the cord feed hole unstopped as an air pressure release, heat and phase variance are not a problem.

 

[StradivariusBone]

Onstage makes some amp stands that allow the amp to be placed like a monitor speaker, with it pointing right at the guitarist's head.

I've seen many church bands that do exactly this. Anytime I play with my bar band I use my practice amp as a monitor for my bass in this configuration (though I direct out to the mixer, not miking the amp in that case). I built a stand that looks like this (but I connected the two planks)-