I'm back! And now it's acoustic treatment time..

[conan]

Well, as some people may remember I came to you guys for help a few months ago, found a site for building, found out it was going to be useless, and have eventually been forced to plump for a terraced residential house (ouch). Thanks to your help, the isolation (room-in-room on floating floor) has turned out more than adequate for our purposes despite being in a less-than-ideal location.

With that done, it's now onto the fun part - acoustic treatment. As usual, I will try to be pretty verbose in my explanation of the problem.

To recap, I will be using the studio for dance music production. Tracks are always mastered externally by our record labels so I don't need or expect the studio to sound anything like a multi-million pound mastering facility. No vocals will be recorded in this room (we'll be using an adjacent room for this but as dance music vocals are so heavily processed, you can forget about this for now).

I completely forget the room dimensions, but I can get them from the plans if needs be. There will be a laminate wood floor but apart from that the room is now just bare plasterboard.

1) I would like the studio to sound reasonably flat with minimal additional cost or construction (yeh, don't we all?) However, as I said, I'm producing dance music - not the latest orchestral prodigies - so if I can get a half decent sound I'll be very happy. When working in poorly treated 'studios' I often tend to mix too bright with too much top end and not enough bass/sub-bass. Am I right in thinking that in this scenario, on a simplistic level, I need to control the bass/mid frequencies with bass traps and/or panel absorbers and allow some of the highs to be reflected?

2) I notice in most home studio construction guides (including John Sayer's SAE material) that there is a second frame built out from the plasterboard, filled with insulation and covered with cloth. Have I got this right or am I going mad? What kind of effect does this really have on the sound of the room? If it helps with reflections, would it do any good to build such a construction just on the wall facing the monitor speakers? There really isn't enough space to do this throughout the room.

3) I also note that any studio designer worth her salt cringes at the mention of carpeted walls. I understand the acoustic principles behind such a reaction, but considering that I can cheaply purchase fire-retardant carpet designed for schools, is there any merit to be had for strategic application of this material on walls? If part of the walls were carpeted and split up with proper absorbers/diffusers/bass traps in the right places, would this give me a flat-ish response (carpet absorbing high/high-mid, traps absorbing low/mid) or have I completely misunderstood the science involved?

Thanks guys!

[RICK FITZPATRICK]

Thanks to your help, the isolation (room-in-room on floating floor) has turned out more than adequate for our purposes despite being in a less-than-ideal location...........With that done,.......

You ALREADY built a floating room within a room??????

Holy Moly. I don't think I could even get a permit that fast
fitZ

[frederic]

Conan,

While its nice and all that you have asked for advice, I for one refuse to help you in any way until you post pictures of your studio.

I insist.

Post now.

Immediately.

Do not eat, sleep, or breathe until you resolve my studio photo fetish.

Now!!!

j/k. I really want to see what you've achieved thus far, if you don't mind.

[Rod Gervais]

Originally Posted by conan

3) I also note that any studio designer worth her salt cringes at the mention of carpeted walls. I understand the acoustic principles behind such a reaction, but considering that I can cheaply purchase fire-retardant carpet designed for schools, is there any merit to be had for strategic application of this material on walls? If part of the walls were carpeted and split up with proper absorbers/diffusers/bass traps in the right places, would this give me a flat-ish response (carpet absorbing high/high-mid, traps absorbing low/mid) or have I completely misunderstood the science involved?

I have to be honest - I have actually installed carpet (sparingly) on movable walls in a professional recording studio I constructed - but only the lower 2 feet - and these were glass panel walls.

HOWEVER - i would point out that I do not consider this (as a general rule) a decent method of treatment - and we did not use it anywhere other than those few walls.

I would also point out - that while in the process of doing this - I discovered that the ONLY carpet certified for installation on wall surfaces (regardless of the carpet's flame spread rating) is Berber carpet - so please don't consider anything else if you decide to go this route.

Personally - a lot of this depends on your budget -

There are some good quality plans for DIY low/mid/high bass traps at Ethan's web site - you can check them out by going to see Ethan at musicplayer.com , you could also consider the basstraps his company manufactures. Please let himn know I sent you.

You can handle higher frequencies with 703 fiberglass rigid boards - lots of available sources for that - check out the sticky in the acoustics forum @ recording.org. You can do a variety of fabric covers on these for finishes. JUst be certain to either purchase flame retardant fabric - or apply a flame retarder to the fabric yourself.

Auralex has quite a few options in the area of foams for treatment. You can check them out at Auralex.com.

I hope this helps some. I can't really offer you much more than this due to the fact that treatment is NOT my specialty.

Sincerely,

Rod

[Innovations]

The best bang for the buck is to get 3 pound per cupic foot fiberglass or rockwool (the famous Owens Corning 703 or equal) Stack it up in a thickness for your purpose, wrap in felt of burlap and attach to the walls with an air gap behind them. The reason for the air gap with fiberglass-type panel is so that whatever does not get killed the first time bounces off the wall and gets taken care of on the return trip.

So, then it becomes a matter of what frequencies do you want to kill? If what you are observing is that your mixes have to much high then you are assuming correctly, bass in building up in the room and making it feel like there is more bass than there is. For bass absorbtion you want panels at least four, preferabley six inches in depth and locate them near the corners where bass builds up. Note that these panels will absorb all frequencies, so your bass traps may be all you need period. However if your room has parallel walls you may also be getting slap echoes, in which case some thinner panels, or diffusers, on the parallel walls may be needed.

That is the basic DIY approach to treatment. To do it really well you should actually set up a test mic and do some serious tuning and testing.

[conan]

Fear ye not, as the camera has been busily snapping away during construction. I will stick everything up in one go when we're done.

Originally Posted by frederic

Conan,

While its nice and all that you have asked for advice, I for one refuse to help you in any way until you post pictures of your studio.

I insist.

Post now.

Immediately.

Do not eat, sleep, or breathe until you resolve my studio photo fetish.

Now!!!

j/k. I really want to see what you've achieved thus far, if you don't mind.

[conan]

*cough* what's a permit? I had a professional check the building wasn't going to fall down and actual application of building regs are loose enough over here to get away with something like this as long as we don't cause anyone any problems. We have a good relationship with the neighbours who enjoy getting involved in what we do so there will always be communication about the only potential problem (noise).

Originally Posted by RICK FITZPATRICK

You ALREADY built a floating room within a room??????

Holy Moly. I don't think I could even get a permit that fast
fitZ

[conan]

Cheers Rod/Innovations. Just one more quick thing on the overall finish of the walls; I didn't expect to be plastering the walls so I only accounted for the depth of plasterboard when making the door casings (d'oh).. Is there any acoustical or other problem in just covering the bare plasterboard walls with flame retardant fabric as I've seen in various mid-end studios? It's purely an aesthetic consideration at this point; should I just give up and get the walls plastered? In any case I shall be building/purchasing bass traps of some description.

Should I also ignore the second frame thing as mentioned at http://www.saecollege.de/reference_m...ages/Walls.htm or is this part of good practice in building a decent studio?

Originally Posted by Innovations

The best bang for the buck is to get 3 pound per cupic foot fiberglass or rockwool (the famous Owens Corning 703 or equal) Stack it up in a thickness for your purpose, wrap in felt of burlap and attach to the walls with an air gap behind them. The reason for the air gap with fiberglass-type panel is so that whatever does not get killed the first time bounces off the wall and gets taken care of on the return trip.

So, then it becomes a matter of what frequencies do you want to kill? If what you are observing is that your mixes have to much high then you are assuming correctly, bass in building up in the room and making it feel like there is more bass than there is. For bass absorbtion you want panels at least four, preferabley six inches in depth and locate them near the corners where bass builds up. Note that these panels will absorb all frequencies, so your bass traps may be all you need period. However if your room has parallel walls you may also be getting slap echoes, in which case some thinner panels, or diffusers, on the parallel walls may be needed.

That is the basic DIY approach to treatment. To do it really well you should actually set up a test mic and do some serious tuning and testing.

[Innovations]

Just slapping fabric over plasterboard isn't going to get you anything in terms of treatment. So it is an appearance thing only. Usually in a mid-end studio that fabric is covering something in the way of treatment.

[conan]

Don't worry, I'm not that thick Hence my asking if there were any acoustical detriment to its use. I saw it merely as an easy way of making the place look okay before any real acoustic treatment is added.

I'm still clueless about what's going on in those John Sayers studio diagrams at the treatment end..

Originally Posted by Innovations

Just slapping fabric over plasterboard isn't going to get you anything in terms of treatment. So it is an appearance thing only. Usually in a mid-end studio that fabric is covering something in the way of treatment.

[Rod Gervais]

Originally Posted by conan

I didn't expect to be plastering the walls so I only accounted for the depth of plasterboard when making the door casings (d'oh).. Is there any acoustical or other problem in just covering the bare plasterboard walls with flame retardant fabric as I've seen in various mid-end studios?

Well you still have to tape - finish and sand clean all the joints - because otherwise they will be seen through the fabric.

But there is no problem acoustically with doing this - and there are some real REAL nice looking fabric wall papers out there (54" goods) that work real well for this.

Rod