Chasing ideal ratios

[SwissCanuck]

Hi everyone, I've been reading these forums for years and have greatly appreciated all the knowledge that's been shared. Time has come now for me to ask a few questions.

First the overview:

The project is a control room and recording space being built into a container, not unlike the contain project John has previously done, only a little larger.

The current internal dimensions of the container are L: 9.66m W: 2.78m H: 2.54m.

As the container was planned for use as a practice room/studio the property owners already reinforced the interior walls with a decoupled MAM, so isolation is not a priority.

As I plan to split the space into a control room and a recording space, the question arises, how much space should be given to both rooms? I know it is often the mantra here that bigger is always better, but playing with John Griggs' room mode wizard, I discovered that by reducing the height of the control room I can accomplish a ratio that meets Bolt's criteria, the EBU 3276 recommendations, and Bonello's Mode spacing criteria. That ratio would be 1 : 1.247 : 1.453. So the control room would be H: 2.23 W: 2.78 L: 3.24, which may be a little cramped, but workable. The biggest issue is the height reduction of 31 centimeters which for reasons of practicality, I would accomplish by raising the floor. I know we're not supposed to say we want to float the floor, but this is the only practical solution to avoid further reduction in width.

So the big question is, is chasing an ideal room ratio worth the effort and expense, not to mention loss of space?

[Soundman2020]

Hi " SwissCanuck", and welcome!

As I plan to split the space into a control room and a recording space, the question arises, how much space should be given to both rooms? I know it is often the mantra here that bigger is always better,

This probably won't work out for a container build, but the general rule is that the live room/tracking rooms should be at least twice the volume of the control room, so that you can hear the reverb tails form the live room, when listening on the monitors in the control room. Less than that, and the acoustics of the control room tend to mask the reverb tails (unless the control room is very "dead", which adds yet another set of issues).

However, reverb tails may or may not be an important part of how you work...

but playing with John Griggs' room mode wizard,

I'lm not familiar with that one, but take a look at Bob Golds' calculator: it gives you a LOT more info than just modes, and might help you make a better decision:
http://www.bobgolds.com/Mode/RoomModes.htm

The biggest issue is the height reduction of 31 centimeters which for reasons of practicality, I would accomplish by raising the floor.

Raising the floor is almost never a good idea: it is equivalent to "floating" a floor badly. see below for reasons why this is a bad idea:
http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

I know we're not supposed to say we want to float the floor, but this is the only practical solution to avoid further reduction in width.

Then don't do it! If you can't drop the ceiling, then definitely do not raise the floor. Why can't you drop the ceiling?

So the big question is, is chasing an ideal room ratio worth the effort and expense, not to mention loss of space?

Probably not. There's a trade-off that you have to make between room volume, room ratio, and ceiling height: If the room is large enough that the volume will still be greater than EBU specs, and the ceiling height will still be above about 8 feet, then no problem: go for whatever ratio you like. But if the ceiling would end up too low, or the room volume is a lot less than spec, the personally I would relax the ratio: go for a "Reasonably good" one, rather than "the best" one. Ratios are useful to a point, but there's no need to go nuts about them. As long as you are far away from the "bad" ratios, and reasonably close to one of the "good" ones, that's fine.

- Stuart -

[SwissCanuck]

This probably won't work out for a container build, but the general rule is that the live room/tracking rooms should be at least twice the volume of the control room, so that you can hear the reverb tails form the live room, when listening on the monitors in the control room. Less than that, and the acoustics of the control room tend to mask the reverb tails (unless the control room is very "dead", which adds yet another set of issues).

However, reverb tails may or may not be an important part of how you work...[7quote]

Hi Stuart, thanks for taking the time to respond!

In this case, the reverb tails of the live space are not so important, as most of the work to be mixed will be tracked in the bigger studio down the road. This space will be used primarily for overdubs/close mic situations and band practise, but I have an idea that I'm going to experiment with later to artificially increase the perceived volume of the space. For now, the primary concern is having a useable mix space.

I'lm not familiar with that one, but take a look at Bob Golds' calculator: it gives you a LOT more info than just modes, and might help you make a better decision:
http://www.bobgolds.com/Mode/RoomModes.htm

You should check it out. It is much more than just room modes, and IMHO a superior tool to Bob's calculator (which I have used in the past).

Raising the floor is almost never a good idea: it is equivalent to "floating" a floor badly. see below for reasons why this is a bad idea:
http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

Yes, I'm fully aware of the issues with raising the floor, which is why I asked the question about ratios. I can however given the depth below the new floor, and the materials I plan to use, get the floor resonance down to 19Hz, which would in addition be mechanically dampened with rubber.

Then don't do it! If you can't drop the ceiling, then definitely do not raise the floor. Why can't you drop the ceiling?

For practical reasons. Lowering the ceiling would require losing some width, which given this is a container, is in short supply. In order to safely lower the ceiling I would have to use vertical supports on the walls in order to support the new ceiling frame. I also questioned what advantage lowering the ceiling would bring given that it too will act like a drum, and the mass required to dampen/lower the resonance frequency is not something I'd be comfortable hanging over my head...

Probably not. There's a trade-off that you have to make between room volume, room ratio, and ceiling height: If the room is large enough that the volume will still be greater than EBU specs, and the ceiling height will still be above about 8 feet, then no problem: go for whatever ratio you like. But if the ceiling would end up too low, or the room volume is a lot less than spec, the personally I would relax the ratio: go for a "Reasonably good" one, rather than "the best" one. Ratios are useful to a point, but there's no need to go nuts about them. As long as you are far away from the "bad" ratios, and reasonably close to one of the "good" ones, that's fine.

- Stuart -

Unfortunately in this case the Height/Width ratio is what kills me, as I can't really get close to a "good" ratio. Without changing that ratio, I'm stuck close to the "bad" ones. Given the width is already tight to place monitors far enough apart without being too close to the side walls, my only real option is to adjust the height. The closest I can get to a decent ratio (Louden's 5th 1:1.2:1.5) without losing as much height would be a height reduction of 19cm or 7.5 inches from my 2.54m/8.3' room height, leaving me 2.35m/7'8", but that comes with the problem of pushing the floor resonace up above 20Hz... What I'd give for a few more centimeters of width...

Alright, thanks for the advice Stuart, I'll try not to kill myself with the ratios too much, and concentrate the funds and energy into treatment for the problems the less than ideal shape creates.