John Sayers' Recording Studio Design Forum Archive

My first post here. Hope you can help...after reading many of the posts, I am quite sure the fine folks in this forum certainly can. i only wish I had come here BEFORE construction!

Construction is almost complete and I am starting to try to tame the live room. I am attaching images of the design. I followed the plans detailed in Everest's book. All of the walls are double leaf with 2 layers of 5/8" gypsum, insulation and caulked beyond belief. The live room is a little over half covered with hardwoods and 1/4" carpet on concrete for the rest. 3 of the walls are gypsum covered with 1/4" "channel carpet". The fourth wall is currently bare gypsum board with 3 doors (w/glass). The ceiling is dropped 6" and made of 1" 703 panels.

The rrom was originally a rehearsal space so not much consideration was given to the sound within the room - just keeping sound from getting out.

The room is about W 17' x L 25' x H 11'.

Here is the big question: It is now time to start to get the room sounding better. I have built a bass trap in one corner - floor to ceiling- by cutting off the corner with 2" of 703. I was planning on placing slats across the the trap this weekend to make it into a slat absorber. The slats are 2.5" W x 3/4" D finished birch. How big should the spaces be to acheive a lower frequency absorption and some high/mid diffusion? Will I need more bass traps? What about other absorbers - any suggestions would be greatly appreciated.

Also, I have placed 8 3' x 4' birch boxes on the wall which are mounted abot 6" from the wall on mounts that allow them to rotate about 40 degrees. This really helped to kill the standing waves and made the room sound more live. i also suspended 4'x8' panels with varying diameters of cardboard tubes on them (sealed airtight at both ends of each tube) to act as diffusors and they actually work well.[/img]

Here are the drawings.....i hope:

These are my initial ideas.

cheers
JOhn

That's a nice big space. If you want it live, but not too boomy, install a couple panel traps in the corners. Ethan Winer has some great designs on his site for building them.

But overall a room that big won't have too much trouble with modal freqs building up, so you won't have to worry about bass trapping very much. Get rid of that carpet if you can, and finish it off with more wood.

That is, if you do want a lively room. John has some ideas for switchable panels, too.

Good luck!

Kase
www.minemusic.net

thanks for the suggestions! I'm attaching some photos so you can visualize it a bit better. Also, I completed the corner trap and ended up spacing the slats at 1/8", 1/4", 3/8" and 1/2". I also built another bass trap (i think) above the sound lock door (see photo). It is a 2'x3' opening covered by 2" 703, about 2' of airspace behind that and then a series of 4" foam squares (24"x24") placed vertically in a row across the rear with about 4" between each square. The cavity is air sealed and about 4' deep.

I have an abundance of birch wood and I am trying to add some wood to the room as I intend to use it primarily for drums. I'm pretty sure all of the highs are taken care of with the channel carpet and the bass is quite a bit punchier with the addition of the traps, but do I need more? I was planning on making a large panel absorber for the rear wall - is it necessary?

Looking Nice!

You might want some variable acoustics in a space that size. How about some gobos and live flats too?

Best,

Dave

ps - seems with as much work as you have obviosly done, why not get an acoustician or some equipment and run some numbers on the space too?

I don't have much to add but nice studio!! I like your color use around the rooms, very cozy.

Ron

You might want some variable acoustics in a space that size. How about some gobos and live flats too?

I certainly will. In fact, I'll attach a photo later of one of them. It is a wooden base (just like the ones on the wall) with hidden casters so it rolls. There is a frame which attaches across the midpoint and has birch slats on both sides. I have about 8 or 9 of these. I was going to put 703 on one side and leave the other side birch. They can be moved around the studio with ease and they are reversible.

ps - seems with as much work as you have obviosly done, why not get an acoustician or some equipment and run some numbers on the space too?

Definitely! I have a Behringer EQ that I have kept around for that exact reason. It has a real time analyzer. There were some basics that needed to be taken care of for sure (bass traps and the addition of some wood surfaces) and I'm just about ready to try fine tuning. Any help on this process would be much appreciated as well (i.e. what type of mic should I use as the reference and do I need to compensate for its natural frequency response?)

Any help on this process would be much appreciated as well (i.e. what type of mic should I use as the reference and do I need to compensate for its natural frequency response?)

No experience with that here.

Maybe we can get an acoustics person to pipe up. Would make for an interesting discussion.

Best,

Dave

My immediate concern would be the carpet walls. These walls are going to absorb all the highs above 1Khz and leave the rest.

If you look at the formula for reverb time you'll see that it's based on absorption sabines V AREA covered. So whilst you have a nice corner slot absorber in ratio to the room area it isn't very much. On the other hand your ceiling absorption covers 1/6th of the room wall area.

the aim is to balance the absorption across all frequencies so I would suspect the low - lowmids area is deficient in that room and the room would sound somewhat boxey.

Adding more panel absorbers and slots would lower the low/low-mid verbtime without affecting the high end so I'd replace the carpeted area with more absorbers in that range.

cheers
john