John Sayers' Recording Studio Design Forum

Post removed.

Post removed

Hi there Gilles, and welcome to the forum!

Sorry about the slow response: busy times, end of year, not too many moderators around, slow internet connection...

With dimensions of 26' by 13', those are far more than minor! The length is exactly double the width, so all axial modes related to those two will line up perfectly with each other. The only way it could be worse is if the height is also a multiple of those two.


Not helping much... It is pretty closely related to the other two. Major red flags waving all over your modal response plot...

For example, at 43.5 Hz. you have both the 0,1,0 axial and 2,0,0 axial perfectly superimposed. And at around 87 Hz you have a grand total of SIX modes, all lined up almost perfectly (2 at 86.9, 2 at 87.0, and 2 at 89.6) I would hat to play a kick drum or bass guitar in that room...

Is that before or after the above measurements? In other words, does that 7'6" refer to the height of the outer leaf ceiling, the bottom, of the joists, or the final dimensions of the inner-leaf ceiling?

And forget that "Acoustiblok" stuff: it is just glorified MLV, which is another way of saying "really expensive mass" that you don't need. When you see claims like "Each layer of 16 oz. Acoustiblok reduces sound transmission by as much as 30 dB ", you just have to laugh... So with four layers of that stuff you could get 120 dB of isolation? Or about one hundred times better than Galaxy studio, which is the best isolated studion on the planet, at at bit over 100 dB? I found that just a little hard to believe...

There are no magical materials that bypass the laws of physics. No matter how much you pay for it, mass is still mass, and since sound waves can't read the price tag, they really don0t care how much you paid for it. All they see is the amount of mass, and they respond accordingly: Two layers of 5/8" fire-rated drywall on hat channel and RSIC clips will give you pretty good isolation. You didn't say how much you isolation you need, but that's a good start (assuming that there is enough mass on the other leaf, and that they are both properly sealed, hermetically, and kept fully decoupled.)

so why are you going to all that trouble and expense to isolate the ceiling, when you do not plan to isolate the walls? If you aren't going to isolate the walls then clearly you don't need much isolation at all, so there isn't any point in isolating the ceiling like that.

The way you describe it above, there is only a single leaf for wall isolation...

Once again, that is only a single leaf, so not much isolation.

It would help if you could describe what your isolation goals are, in terms of decibels. Without knowing that, it's hard to say if any of the above will be sufficient or not.

Great! A two-leaf MSM isolation wall: But that's assuming that the studs are NOT attached to (or even touching) the concrete wall: Is that correct?

Is that just for decoration? If you just attach wood slats to the drywall surface, all you have is a pretty surface. That isn't a slot wall, and has no acoustic effect (except for some diffusion, probably). So if that is just intended as decoration, then you are fine, but if it is intended as a slot wall then you need a sealed cavity behind the slats.

Well is it s slat resonator is it a bass trap? It can't be both. Slat resonators are very inefficient down at bass trap frequencies. The sizes of the slots and/or depths get pretty unmanageable as well, when tuned so low. And what frequencies will you tune them to?

It's VERY appropriate for the forum! Absolutely! Exactly what the forum is meant for.

It would also help to know more about the control room, since there are recommendations that should be taken into account when designing a live room for an existing control room. For example, the volume of the LR should be several times that of the CR, if possible, and the reverb time of the CR should be no more than half that of the LR, in order to ensure that reverb tails are clearly audible in the CR, and not confused in the CR's own RT. Etc. They should be design in harmony, to work together, so it would help to know more about the CR in order to help you design the LR better.

But to me, it seems that the biggest issue by far is the modal response issue: there's just so many red flags there that I'd seriously suggest shortening the room enough to get that under control. You also didn't mention the plan for ceiling treatment, but I get the impression that the overall concept here is to have a rather bright, resonant room, rather than a soft, warm or dead one. Is that what you are looking for?

Also, actual photos of the room as it is right now, and close-ups of the existing materials and structures, would help to understand it better.

One other thing you could do, is to set up a good full-range speaker and a measurement mic in that room, and measure the current acoustic response (using REW), then post the data file here for analysis. I would do one reading with the speaker in one of the room corners and the mic in the diagonally opposite corner, then another reading with the speaker set up in the proposed drum kit location and the mic in the area between the mechanical room and the diffusers, well clear of the walls. That test would reveal a lot about the room, but I'm betting that there will be very visible issues at the modal points I mentioned above, and I strongly suspect that those will be your biggest headache!


- Stuart -

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I want this studio to amaze people. "That'll do" doesn't amaze people.

I have removed the post and related images because we will hire an acoustical engineering firm to save ourselves some frustration and a lot of time. Thank you for your time Stuart and best regards.

Gilles