John Sayers' Recording Studio Design Forum Archive

I'm interested in treating my large single room acoustically for mixdown and tracking purposes. I have no neighbors or soundproofing issues, just wanting a room good for mixing and tracking.

The room is a large room (30x35) with an 15.25' ceiling that drops to 9 feet in the back. The triangle wall from the drop ceiling at the back of the room is 11 feet from the back wall.

The room has commercial carpeting and a medium pad underneath. The room is currently untreated and echos and flutters badly with hand claps.

I have the following mics if those are useful for measurements but honestly how no clue what i'm would measure, how meaningful the measurements will be and if I even need to measure anything. Studio projects C3 cardiod/8/omni, Shure SM57 and Shure 87 beta hyper cardiod. I also have a Radio Shack Sound Level Meter.

I would like to bring this up to pro quality acoustics if possible using DIY products. I track, mix and master rock and roll at about 95dB during recording and about 89dB during mixdown. Please advise me if I can provide more information or if I missed anything.

All side walls have two sheets of 1/2" drywall directly attached to each other for 1" thickness. This was done during construction and I don't plan on modifying it.

Since I have so much carpet, I can bring in some hard floor surfaces if needed for vocals, like a 4x8 plywood or harder wood for a singer to stand on if needed. I don't have any noise issues as my HVAC is off a lot and very very quiet when on and my DAW is very quiet.


My understanding is that larger rooms are easier to treat but I don't know if that is really true. Also, I don't know how critical my offset mix position is. I can move it and the speakers if necessary. I also hear that having the speakers pointing down a bit like I have is bad so I might make some stands and lower them. So far imaging seems to be no problem but bass control and flutter a major problem.

Will my windows cause problems ? They are thick laminate windows including the large one in the back of the room.

I can DIY and would like to know what a couple of choices might be. Cost no object, < $2000 and < $750.


Thanks for the advice !

John Bercik

The first thing you need to do is slide your monitoring setup over so it's centered left-right in the room. The carpet is fine, but you need plenty of broadband absorption to tame the reverb and the LF peaks and nulls and ringing. Windows are not usually a problem unless they're at specific reflection points. Much more here:

Acoustic Basics
How to set up a room
Early Reflections

--Ethan

thanks for the reply but can you be more specific? how much and where, like:

Do i need corner traps going from the ground to the ceiling in all corners?

Do i need panels on all walls 6" thick, 4" off the wall and how many?

Do i need a cloud hanging overhead and what if so what size? (8' x 8')

Where should the speakers be positioned exactly and where should my listening position be?

I can DIY and would like to know what a couple of choices might be. Cost no object, < $2000 and < $750.

Is it true that large rooms need less treatment ?

How do you take my drop ceiling and triangle wall into account too?

Thanks in advance, I have been reading a LOT include those articles but do not know how to get from the theory to specifics.



happy holidays

How many traps you have depends on how much you're willing to spend versus how much improvement you want. You don't "need" anything, but the more traps you have the closer to a flat response you'll get. In a room that size even 30 2x4 bass traps and other panels would not be too many. Heck, 50 wouldn't be too many. But generally, Yes, larger rooms can get away with less treatment proportionally because the reflecting surfaces are farther away (mid-high frequencies) and the bass modes are closer together (low frequencies).

To be much more specific requires more time and effort than I can offer in a forum. But the theory for knowing how large a cloud you need, for example, is not complicated. Make it large enough so you don't receive early reflections anywhere in the area where you move your chair around while mixing.

Even as an acoustics "expert," I've added treatment over time in both my 33x18 foot home studio and my 25x16 foot living room.

--Ethan

Thanks Ethan. Your generosity is truly beyond anything i have seen. I really enjoy your videos too.

Would 20 48x24x2 inch 703 traps give more bang than 10 48x24x4 inch ones for trapping bass ?

Would i need a cloud since my ceiling is angled overhead?

I should get about 5000 of your pico traps! Heheheh. Hilarios stuff!

Does it make more sense to have bass traps directly behind the free standing control room speakers where they can absorb at the source than against the wall?

The info at the bottom of this page seems to indicate that my speakers should either be very close to the wall or at least 5'4". Is that right?

http://www.genelec.com/documents/qsg/QS3-way.pdf

Also, i currently tilt my speakers down a bit to point the tweeters to my ears. It seems this would reduce reflections a bit by not aiming directly at a wall. Is this ok too?

You really need a mix of 2" and 4" thick panels, not just one or the other.

Reflections happen at the room boundaries, so that's the best place for absorbers, rather than out in the room.

Ideally loudspeakers should have their tweeters at ear level, not higher and pointing down.

--Ethan

in addition to Ethan's input, i'd suggest hanging some clouds from the peak and on the low edge of the drop down section of ceiling to add additional trapping on that peak and to reduce reflections off that flat surface. agree on the monitors being ear level - just treat the key reflection points on the side wall, ceiling angles, and rear wall. optionally you could build-in some treatments as an alcove and turn the mix desk so the ceiling slopes up and away. this can also help with some isolation with instruments in the room.

thanks for the nice reply. i'm not clear on the picture though. i don't see my room in that picture. more info please. thanks again.

basically wall off a small section to about 6 or 7' leaving the rest open overhead and build out wall treatments to flatten the corners and add broadband absorption and diffusiveness. attached is drawing overlaid on your room sketch.

I see it now. Thanks but that is more change than i want to do to this room. When i sell the house i want to be able to easily remove the treatments and leave a nice big open room. Also Ethans 50 trap idea scares the hell out of me. Is there any economical solution short of mixing with headphones? Thanks for all the tips.

make the "walls" portable. while it's still going to take quite a bit of work, you could build a number (12 or so) slat resonator boxes and another 15-20 absorbers, etc. this way you can partition the space bit and readily move it when needed. another option is the "it's a home theater" pitch on the CR when it comes time to sell...

why does the mixing area need to be smaller ? Can't I treat the large room economically and keep it open?

Also, what do the slat resonator boxes do ?

depends on your needs. the treatments as shown create a mostly symmetrical space for mixing which has a bit of isolation (ala gobo) which may help in tracking. if you don't feel that constrained symmetry will help your mixing then just go with the centered placement on a given wall and treat the open space. the slat resonator boxes add broadband absorption and are diffusive which help in preserving room energy. spacing out your rigid insulation absorbers helps bring down the room RT60 to the level you desire. you could also use polys across the corners for the bass trapping and diffusion.