Help with Room Acoustics and Acoustic Pannels

[Sigmund451]

Ive been chasing some really strange sounds. First I thought the problem was the guitar. Then I thought it was the speaker cabinet. After going round and round trying to fix the problem I found it was the acoustics in my practice room and Im seeking some basic advice.

Some bass notes are just crazy. A couple go Thunk Thunk and a couple of others are really loud and are just not right. Im no sound expert but it seems like Im getting wave cancelation and more.

The long and short of it is that I hung some quilts on the opposite wall from my amp. I also closed the heavy curtains over a set of double glass doors and a large window since glass reflects sound waves like crazy. Additionally, all of my walls and celing are VERY hard. They are plaster over block (French construction). The blankets really helped a great deal.

I am assuming acoustic foam pannels are the easiest solution since I dont want blankets hung around the room.

They make quite cheap foam squares (egg crate and different designs). Assuming that I find the proper placement should these work? Im not recording. I dont need a perfectly dead space but Im not ok with my room making my guitar sound like it broken. My playing does that enough on its own.

Thanks in advance.

[fep]

If you play your guitar through headphones and it sounds fine, you can eliminate the guitar as being the problem.

Much of the cheap foam does very little or maybe nothing when it comes to low frequencies. This is a good resource: Acoustic Treatment and Design for Recording Studios and Listening Rooms

"Bass frequencies are the most difficult to tame in the small rooms many people use to record and mix their music. One common problem is a mix that sounds great in your room is too bassy when played anywhere else. The culprit is bass waves bouncing off the wall behind you, creating deep nulls in the response you hear. Nulls as deep as 30 dB are not only common, but typical. Most small rooms have several nulls in the bass range below 300 Hz.."

[Sigmund451]

I will study on that article, thanks.

To be clear the biggest offenders are the 6th string around the 7th fret. They like to go thunk in the absence of the quilt across the room.

The fifth string around the 12th and 13th fret like to do something I cant really describe.

Both of these points on the guitar are imperfect tones on my carve archtop but they are subtle and can be lived with when the room has some treatment. In the untreated room the slight variance on those tones becomes exponentially worse and not simpy due to ampification.

If it helps the room is about 12x12 in feet...bedroom size.

[Bob_Ross]

If it helps the room is about 12x12 in feet...

That absolutely does not help you ...one of the worst possible scenarios for taming small room acoustic anomolies is a room where any two dimensions are identical.

But it does help to know that that's what you're dealing with.

Shallow foam, eggcrate-shaped or otherwise, will have no effect on the low frequency modes that you want to address. Your best bet is to straddle the corners -- either the 90° corner formed where every two walls meet, or the 90° corner formed where every wall meets the ceiling (and, if possible, straddle the entire corner, floor-to-ceiling or wall-to-wall) -- with 2' x 4' x 4" thick 6lb/sq.ft. rigid fiberglass insulation. If possible, get the "faced" type, and orient the panels so the face is pointing out into the room.

These will act as rudimentary -- but surprisingly effective -- bass traps, and they will tame most of the low frequency anomolies that may be encountered in a small room.

If you wrap the panels in an acoustically transparent fabric, they can even be fairly stylish in appearance, and pass the W.A.F. test.
Make sure the fabric is also flameproof.

[Aiq]

Second on Mr. Ross.

My music room is square. Carpet on the floor, heavy drapes over the one window, rugs on south wall, foam squares on the north, west, and east walls.

The single most helpful was placing foam bass traps in the four corners. Not expensive either.

The room is pretty dead now.