John Sayers' Recording Studio Design Forum Archive

Hey guys! A couple of years ago I re-designed my studio with fantastic result, owing in no small part to the kind members of this forum!

Now I'm on a different mission. I have a rehearsal space which also contains a big mixing desk and lots of recording gear. It's been used for recording but because of almost no acoustic treatment or accurate placement, mixing has been pretty much impossible.

Now I want to change that. Not shy of building stuff, but need to keep costs as small as possible.

The room is roughly 7,5x12, meters, ceiling kind of low at 2.4 meters. I want to place the speakers on the mixer bridge. Acoustics don't need to be perfect, but good enough for basic mixing and production, and also for rehearsal.

I have some material already, which I can use if there's some good use for it:

1. 12 wall modules, 0.6x2 meters (previously used to build a vocal booth). I'm thinking about using these to kill corners.
2. roughly 4sqm worth of high quality diffusers (planning to use where most crucial, and add more simple 2D diffusers if needed)
3. Lots of absorption panels, 1x2m, 10cm thick, currently used on the walls to dampen sound for rehearsals, and also a couple hanging in the ceilings here and there.

My plan as it currently stands is to put 0.5m of insulation across the whole of one of the 7.5m walls, floor to ceiling, to make one big broadband absorber (supported by wood panels, then covered with fabric), then put the mixing desk up to that wall, in the middle. (shown in blue on the Sketchup doc)
Then I would hang some of those absorption panels in the ceiling, angled, above the mix spot.

I'd love some advice on this plan, or other suggestions how to plan and build. Thanks in advance!!

Sketchup Pro file here: https://www.dropbox.com/s/lhlbhtcl9626e ... h.skp?dl=0

Cheers! /Rasmus Faber

Simplification + bump:

I have a big room used as rehearsal space. I want to be able to also mix in it. Planning to build a 50cm absorber on the whole of one of the walls and put the mixing desk and speakers up against that wall, in the middle.
Then adding some ceiling/corner absorption and diffusers as needed, but basically hoping the thick wall absorber will be doing most of the work.

More details in post below, would love to hear some thoughts!

I want to place the speakers on the mixer bridge.

That's never a good location for speakers. Yes, you often do see studios that have speakers on the meter bridge or dog box, but those are not the main speakers: they are there for checking how the mix will sound in a typical not-so-good environment, not for the actual precision mixing.

If you have meters on the bridge, you will get serious comb filtering and mid-range issues, as well as possible early-early sound, from vibrations in the desk itself, and reflections off the console surface. The frequency response will be a mess, there will be no clarity in the sound-stage, and it won't be a good way of mixing at all.

Put the speakers on stands behind the desk, in the correct geometric relationship to the room and the mix position.

1. 12 wall modules, 0.6x2 meters (previously used to build a vocal booth). I'm thinking about using these to kill corners.

What are the made of? What is the acoustic absorption material in them? How thick is it?

2. roughly 4sqm worth of high quality diffusers (planning to use where most crucial, ...

What frequency range are they tuned to?

3. Lots of absorption panels, 1x2m, 10cm thick, currently used on the walls to dampen sound for rehearsals, and also a couple hanging in the ceilings here and there.

Same question as above: What are the made of? What is the acoustic absorption material in them?

My plan as it currently stands is to put 0.5m of insulation

What type? What gas flow resistivity?

then put the mixing desk up to that wall, in the middle.

... then you would have your room backwards! The best arrangement is to have a reasonably live front wall with treatment only in the locations where it is needed, and a mostly dead rear wall, since the rear wall is generally the biggest source of all types of acoustic problems, notably SBIR, comb filtering, axial modal issues, etc. The rear wall needs deep treatment across the entire surface toe deal with that, and possible diffusion elements in front of that, if the room is large enough to permit that.

Then I would hang some of those absorption panels in the ceiling, angled, above the mix spot.

What about your first reflection points on the walls? those are just as important as the one on the ceiling, and probably even more important, depending on the characteristics of the speakers.

- Stuart -

Hi Stuart! Thanks for chiming in!

Put the speakers on stands behind the desk, in the correct geometric relationship to the room and the mix position.

True, we should be able to do that!

1. 12 wall modules, 0.6x2 meters (previously used to build a vocal booth). I'm thinking about using these to kill corners.
What are the made of? What is the acoustic absorption material in them? How thick is it?

They are 10cm thick, which I think is 2cm of plasterboard on each side, with 6cm of rock wool in the middle.

2. roughly 4sqm worth of high quality diffusers (planning to use where most crucial, ...
What frequency range are they tuned to?

2000-16.000

My plan as it currently stands is to put 0.5m of insulation
What type? What gas flow resistivity?

I don't know the english terminology, but the regular softer kind.

... then you would have your room backwards!

Thats true. I'm actually quite comfortable with a dead front wall too (which I have in my own studio, but there I have a dead rear as well). The main reason for this arrangement is that its very hard to have it any other way. Its quite far to the back wall (14 meters) and that wall would be difficult to deaden for a number of reasons. Best we could hope for is to try and put as many bass traps as possible on the rear wall, but it wouldn't work to deaden the whole wall.
Hence the plan to deaden the front and part of the sides. Not sure if we could arrange it differently but I'll definitely take your comments onboard.

Hmm, one way would be to turn the mixing desk and speaker setup around so it would play into the absorption (with lots of space behind them). Not as nice looking for sure, but something to consider perhaps..

What about your first reflection points on the walls?

Yes, in the current design those are covered as well. The plan is to cover the front wall, and continue that treatment on the sides, reaching about 2 meters on each side (out of the total length of 7 meters)

2000-16.000

So they are tuned only to the highs? Why that range? You could probably use those on the rear wall, provided that there is no critical listening position within 3m. In other words, no place where somebody would normally be sitting or standing while carefully listening to the mix and making decisions about it.

What type? What gas flow resistivity?

I don't know the english terminology, but the regular softer kind.

Then you have a problem! A big problem. If you don't know what type of insulation you have, then how can you possibly know what acoustic response it has? How could you know where to use it, or how much to use? Each type of insulation has different characteristics. Some types are really good for low frequencies, other types are only useful for high frequencies, some types are best for wall insulation, other types are best for first reflection points, and still other types are best for bass traps, or ceiling clouds, or damping Helmholtz resonators. You MUST use the correct type for each application in your studio, or it will be an acoustic mess!

You should probably do some research here, to understand the terminology, and the types, and the applications, and the advantages and disadvantages of each type.

I'm actually quite comfortable with a dead front wall too (which I have in my own studio, but there I have a dead rear as well). The main reason for this arrangement is that its very hard to have it any other way. Its quite far to the back wall (14 meters) and that wall would be difficult to deaden for a number of reasons. Best we could hope for is to try and put as many bass traps as possible on the rear wall, but it wouldn't work to deaden the whole wall. Hence the plan to deaden the front and part of the sides.

You seem to be misunderstanding the concept of what a control room should be. A correctly designed control will NOT be dead. It won't be live either. It will be neutral! That's the goal for any control room. Not what makes you feel comfortable, or sounds "nice". The correct acoustic response of a control room is laid out clearly in specifications such as ITU BS.1116-2, and AES TD-1001, and EBU TECH-3276. They all say the same thing: the control room must be acoustically neutral, the frequency response of the room must be flat such that it does not "color" the sound in any way, by adding something to it, or taking something away from it. The goal is that the engineer sitting at the mix position can hear ONLY the direct, clean sound of the speakers, and NOT hear the room at all, except for a neutral, smooth, even reverberant field that arrives 20ms after the direct sound, and decays consistently across the entire spectrum at the same rate, which is given by the dimensions of the room.

If you make either the front entirely dead, or the back entirely dead, then you will not achieve that. Each part of the room has to be treated correctly. There are several design philosophies that accomplish that, such as RFZ, NER, MR, CID, ESS, and variations on them. Some of those are extensions of the very old (and obsolete) LEDE design, which is similar to what you seem to be describing (except backwards), but nobody in their right mind builds true LEDE rooms these days: that's a concept from 40 years ago, that proved to be not very good in practice. Modern design concepts eliminate the bad problems with LEDE while keeping the good part. Here's an example of a properly designed and treated RFZ style room: http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471 You can see form the graphs that it is totally neutral. Not live, not dead. Acoustically perfect for a control room.

Hmm, one way would be to turn the mixing desk and speaker setup around so it would play into the absorption (with lots of space behind them). Not as nice looking for sure, but something to consider perhaps..

Not a good idea! There are very specific guidelines for setting up the location of the speakers, mix position, and basic treatment in a room, in order to get the correct acoustic response. It's not a matter of guessing, and wondering, and trying out "maybe this, maybe that". Rather, it is about using the math and the guidelines that work, and applying them to your room. If you set it up correctly, and treat ti correctly, then it will be neutral, or close to neutral. If not, then it wont, and your mixes will suffer: then might sound fine in the room, but they won't sound so good when played in other places...

The plan is to cover the front wall, and continue that treatment on the sides, reaching about 2 meters on each side (out of the total length of 7 meters)

That would basically trash the room, acoustically. It would way over-treat the front, while not dealing with the real issues, and leaving the rear incorrectly treated.

Take a look at BS.1116-2. That will show you what you need to aim for, in order to have a room that can be used as a control room.


- Stuart -