Acoustics Problem in Drum Room

[Chris-P]

Room Details

• 12 feet wide, 13 feet long, 7 feet 9 inches tall
• Floor: Concrete covered with carpet
• Walls: Two layers of 5/8" sheet rock with Green Glue in between each layer.
• Isolation clips on ceiling.

Current Acoustical Treatment

• Auralex 2" wedge on every vertical wall starting at the base board and going up three feet (mid wall)
• Auralex 1" wedge foam on every vertical wall starting at the ceiling and going down 1 foot.
• No acoustical treatment on the ceiling. (I suspect that this may be the culprit as the ceilings are pretty low

The Problem
Despite all the Auralex foam, I have a ton of echo and slap back. This is manifests in terrible microphone feedback when my band practices. I currently use a Sennheiser vocal mic with a very narrow pick up field and a gate. This helps a bit but the feedback is still a big problem.

What I Want to Know
What is the most efficient and cost effective way to go about improving room acoustics to reduce microphone feedback. I don't want to drop another $300 on Auralex with minimal effect.
IE - What should I use and where should I put it?

[jbassino]

Read the stickies

[Chris-P]

Yeah, so there are 13 stickies. Can you narrow it down for me?

I read the "READ BEFORE YOU POST" one.

[Soundman2020]

...I have a ton of echo and slap back. This is manifests in terrible microphone feedback when my band practices

that's three entirely different problems! Feedback is one thing, echo is another, slap back is yet another.

#1. You cannot fix feedback with acoustic treatment (or at least, not very much). That is almost purely a sound engineering problem: You have too much gain in your system for the current microphone and speaker positions and oreintations. You have three options: move/re-orient the mic, move/re-orient the speaker, or reduce the gain. Period. There are no other solutions. well, sure, you could buy a feedback suppressor / eliminator / destroyer, but that is still a gain reduction device, not an acoustic treatment.

#2. Echo. You don't say what type of echo, so I'm assuming flutter echo. That is caused by hard acoustically reflective parallel surfaces. If you cannot re-build the walls at an angle. then the next-best way to treat that is with absorption, such as large thick mineral-wool or fiberglass absorbers. Several full panels of 703 would work great. Search the forum. You only need to treat opposite surfaces, and you can do it in a "checkerboard" patter if you want. The idea is that every "hard" surface in the room faces a "soft" surface on the other side of the room.

#3. Slapback: It's hard to see how you can have a slapback problem in such a small room! It isn't long enough for the minimum round-trip delay necessary for your brain to identify the echo as being an echo! Maybe you are talking about room modes or resonance?

Floor: Concrete covered with carpet ... No acoustical treatment on the ceiling. (I suspect that this may be the culprit as the ceilings are pretty low

That would be the reason for the dull, muddy, boomy sound of the room. Read the forum to understand the concepts, and how to treat it.




- Stuart -

[Chris-P]

Stuart,
Thanks for your reply.

You're right, I got my terminology mixed up. What I have is quite a bit of flutter echo.

I'll look into constructing some 703 panels.

Would you recommend attaching those to the ceiling as well, or is there a preferred solution for ceilings.

[xSpace]

"Room Details

* 12 feet wide, 13 feet long, 7 feet 9 inches tall
* Floor: Concrete covered with carpet
* Walls: Two layers of 5/8" sheet rock with Green Glue in between each layer.
* Isolation clips on ceiling.


Current Acoustical Treatment

* Auralex 2" wedge on every vertical wall starting at the base board and going up three feet (mid wall)
* Auralex 1" wedge foam on every vertical wall starting at the ceiling and going down 1 foot.
* No acoustical treatment on the ceiling. (I suspect that this may be the culprit as the ceilings are pretty low"

Your wedges are not in a position to help you. Three feet from the floor and one foot from the ceiling still leaves all the wall area open that can directly influence what your ear's hear. What is that 3' 9" of vertical hard surface still slapping you around, about from your waist to the top of your head?

A quick fix would be to move them from the below the knee area and up to at least your head/ear level. Then read on some of the information the others suggested and go from there.

[Chris-P]

xSpace: The wedges are somewhat permanently in place so I was thinking about building a few 703 panels and putting them at the height you suggest. Do you think I'd need some ceiling treatment as well?