Bass Trap Advice

justanotherjo

New member
Hello Everyone:

I have some questions about treating a room, and I’m hoping you’ll be able to provide some advice—but then again, why else would I be posting?

First, though let me give you some context. I’m a high school English teacher. The shop teacher at our school has put together a nice little studio in one of the music practice rooms. He has actually installed a lot of his own equipment in the studio, and the studio is more or less his baby. The music teacher is not really interested in recording, but the studio is in his territory. Why am I telling you this? Because I don’t have a lot of control over how things will be done, and I can’t do things exactly the way I want to do them. The questions I am asking stem from trying to meet their concerns.

Anyway, the control room is in need of treatment. The room is basically 10 x 15. One of the walls is at a slight angle (maybe 10 degrees off square) and there are windows on two of the walls (including the angled wall). The walls are painted cinder blocks. They are about 10 feet high. The room has a drop ceiling, and I’m not exactly sure how high the actual ceiling is but it is probably an extra six to eight feet. The walls also end at the drop ceiling, and we have a cavernous space for the ductwork above that must be about 15 x 60.

We have access to an almost unlimited supply of midrange and high frequency absorbers (foam covered with fabric). They presently line the room, and the room is almost dead for those frequencies—almost too dead if you ask me. The room has not yet been treated for the bass frequencies.

I want to add some bass traps. Putting rigid fiberglass panels across the corners wouldn’t work because of the windows, door (in the angled wall) and the non-square corners. Also, we would lose too much space.

I would like plywood panels with rigid fiberglass—hoping as well that these might liven up the room a bit for the midrange and high frequencies. The problem is that the other teachers don’t want to attach anything permanently to the walls. Would the traps work as effectively if they were suspended from the ceiling beside the wall or made into a freestanding unit? Could we just lean the trap up against the wall? If the trap were built to be self-contained would you use plywood on both sides of the traps, or would it be more effective to use drywall or some sort of drywall-like/masonite product for the back?

Also, is there an effective way to treat the drop ceiling? Would putting rigid fiberglass on top of the ceiling tiles help.

Thanks for the help.

Joe.
 
That's a pretty complicated room.... Depending on the monetary resources at your disposal, I would consider bringing a professional in to take a look.

On the other hand, while your room sounds extremely complicated, with various details of oddity (from the norm), I think we can help you out.

This may may sound like a cop-out, but please bear with me. Do you suppose you could provide a diagram of the space, with some dimensions (width's of windows, especially). Also, a few pictures would be great too...

Trust me, we've got all kinds of people around here, including myself, who love to pick apart these topics as a hobby. However, I for one am very inefficient without visuals.. Anything you can provide would be awesome...

Either way, sounds like a great project...

Good luck!
 
Fill the suspended space (or as much as is practical) with fluffy insulation to help it all act as a bass absorber.
 
Thanks for the replies.

Here is a sketch of the room. I was off a little bit with my estimation of the dimensions. The room is closer to 10.5’ x 11’. Also, I was wrong about the walls ending at the drop roof. They go right up to the ceiling. I estimate that there is about 6-8’ of space between the ceiling tile and the ceiling—with lots of vents and wires.

The windows are both 3’ off the floor and approximately 4’x 6’ 7” with a sill about 6” deep. They are thick, double-paned glass.

There are three 3’ x 6’ absorbers foam absorbers mounted 3’ off the ground, along the walls without the windows. They are the yellow boxes on my diagram.

There are also several 2’ x 5’ absorbers resting on the floor against the wall, and across the corners. There is a larger 4’x 5’ absorber directly behind the workspace. They are indicated by the blue boxes.

The mounted (yellow) absorbers were installed when the school was build about 10 years ago. The freestanding (blue) absorbers were made from old office dividers. Knowing our school board, I assume they are somewhat low end products.

The floor is carpeted.

I have also included a schematic of how the equipment is set up—the darker blue boxes are the monitors.

I have had nothing to do with the set up and design of the room so far. I would have preferred to use the more symmetrical room that is adjacent to the studio (there is also another room identical to the studio at the other end of the hall). Also, the others seem reluctant to permanently attach anything to walls. Hence, my questions regarding stand alone unit.

Thanks again, any and all advice would be welcomed.

Joe.

schoolstudioweb4af.jpg
 
justanotherjo:

Here's just a few questions...

Most of them seem rather irrelevant, since you don't have much control over the room's setup... Please also keep in mind that I am a "big dreamer".. So there will most likely be some impraticalities... ;)

Either way.. Here they are...

1) Is the top right room the isolation booth? Is it "deadened"?

2) You have a console and a mixer? I'm confused... Please elaborate.... (I would imagine that you want the main "mixing" device pefectly centerered between the monitors.. and all other things off to the side, generally speaking)...

3) Is there a computer involved? Is it on the desk?

4) Are the monitor speakers on stands?

5) Are the tweeters, of the monitors, at ear level?

6) What kind of carpet, commercial grade? Is it a permanent fixture?

7) Would the shop guy be able to install a hardwood floor?


I was playing around with some ideas.. This, unfortunately, is totally impractical.. Just thought you might be interested in seeing it, anyway... Now there is symmetry, but no way to get in.. Not to mention having to build walls.. lol... Oh well.. I'll wait for more input..

schoolstudioweb4afx0014cw.jpg


P.S. There is also the possibility of using "wrapped" rigid insulation, instead of the current ceiling tiles...

Check out my thread for some info on this...
https://homerecording.com/bbs/showthread.php?t=187929
 
Last edited:
peritus said:
justanotherjo:

Here's just a few questions...

Most of them seem rather irrelevant, since you don't have much control over the room's setup... Please also keep in mind that I am a "big dreamer".. So there will most likely be some impraticalities... ;)

Either way.. Here they are...

1) Is the top right room the isolation booth? Is it "deadened"?

2) You have a console and a mixer? I'm confused... Please elaborate.... (I would imagine that you want the main "mixing" device pefectly centerered between the monitors.. and all other things off to the side, generally speaking)...

3) Is there a computer involved? Is it on the desk?

4) Are the monitor speakers on stands?

5) Are the tweeters, of the monitors, at ear level?

6) What kind of carpet, commercial grade? Is it a permanent fixture?

7) Would the shop guy be able to install a hardwood floor?

Thanks again. I think I'm getting some ideas. I don't think we'll be building walls. :) I'll do my best to answer your questions. I'm not exactly happy with the layout of the room, but I need reasons. I'm supposed to be the newbie.

1) They are using the room on the top right as an isolation room--though it is not completely isolated or deadened. There is also another room above that room that is a mirror replica of the room the studio is in. They are also recording in the main music room. They were recording vocals in all four rooms at one point.

2) What I called the console mixer is basically a rack with the preamps, compressors, firewalls, effects, and so on. The mixer is an analog mixer that is used during recording. The chain is something like this: 1) The signal goes into the mixer; 2) out to the compressor, effects, etcetera; 3) back into the mixer; 4) into the firewall & computer; 5) out to the mixer; 6) to the monitors. I assume he occasionally runs the signals through one of the racked preamps first. I’m not exactly sure though, as I didn’t set the system up.

The mixing is done on the computer—the keyboard and the mouse are on the desk. The computer monitors are on the console/rack.

3) See question (2)

4) The monitors are on stands. They are angled slightly downward.

5) I think the tweeters are slightly above ear-level when seated—though, as I mentioned, angled downward.

6) It’s a commercial grade carpet over a concrete floor.

7) I can’t see the hardwood floor as an option.

Hope this clarifies a few things. Any and all advice is greatly appreciated.

Joe.
 
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