Ideal Room Dimensions

[markbirkett]

Hi Everyone

Newbie question! I am planning to build a recording studio in my front garden and am desperately seeking good advice on room ratios. The garden is 29 feet x 32 feet square in total. So I'm guessing the maximum total usable space is around 28 feet square to give myself a margin around the edges. I've heard that 17.5 deep x 23 wide x 11 feet high would be the "ideal" control room dimensions. However, since I'd hope to be able to record live drums, bass and other musicians in there as well, I'm assuming that I'd need space to put in a double wall with a suitable wide air gap in between. What I don't know is whether that's achievable in this space. If not, are there other control room dimensions I can plan for that will minimise the sound leakage issues as well as give me a decent start sound wise inside? In addition to the control room, I'd like to have space for a separate drum / live room and a vocal booth.

Do-able does anyone think?

Many thanks in advance,

Mark

[Soundman2020]

Hi Mark. Hi. Please read the forum rules for posting (click here)0. You seem to be missing a couple of things!

The garden is 29 feet x 32 feet square in total. So I'm guessing the maximum total usable space is around 28 feet square to give myself a margin around the edges.

You'd be leaving a hell of "margin around the edges", to reduce 928 square feet to just 28 square feet! Something funny happened to your dimensions on the way to the keyboard...

I've heard that 17.5 deep x 23 wide x 11 feet high would be the "ideal" control room dimensions.

There is no such thing. There is no "perfect" or "golden" or "ideal" ratio for a studio. There are only good ones and bad ones. Over the decades, many scientists have conducted numerous experiments and mountains of research, and their names live on in the sets of good ratios they came up with: Names like Louden, Sepmeyer, Volkmann, Boner, Bonello, Bolt and others. Despite all that research, not one of them was able to identify a "perfect" ratio, or even an "ideal" one. Bolt came up with a graph that shows an entire range of ratios that are reasonably good, which is often called the "Bolt area" these days. The ratio you gave (1 : 1.59 : 2.09) is not particularly good at all. It is within the Bolt area, yes, but it still fails one of the three "critical" tests that BBC acousticians apply to determine if a room can be used as a control room or not (because the height multiplied by 2 is within 5% of the length). The Bonello plot is also not very smooth, meaning that there is not a good distribution of low frequency modes.

I have no idea where you got that ratio from, but it isn't ideal by any means, and I would never design a room with those dimensions if I could avoid it.

However, from your description, it is also not clear what room are referring to here. On the one hand, you say " since I'd hope to be able to record live drums, bass and other musicians in there", but on the other you say "...are there other control room dimensions...?". So are you talking about a live room / tracking room? Or are you talking about a control room? Those are two very different things, acoustically. Drums would sound terrible if recorded in a good control room, and a control room would be pretty much unusable for mixing if it had the acoustic response needed for great drum recordings... Or are you talking about having both a control room AND a live room with the same dimensions? If you really do have 900 ft2 then you certainly have plenty of room for having two rooms, and more. (But if you only have 28 ft2 then you barely have room for a broom closet! ) Either way, it would be a bad idea to have the LR and CR with the same dimensions, or the same ratio. The general room of thumb that designers us is to make sure that the volume of the LR is about 3 to 8 times the volume of the CR, with 5 times being about the best you can hope for.

I'm assuming that I'd need space to put in a double wall with a suitable wide air gap in between. What I don't know is whether that's achievable in this space.

With over 900 ft2, you have more than plenty space to do a full commercial studio facility, with a live room, control room, iso booth, vocal booth, bathroom, green room, kitchen, and storage area. That would, indeed, include fully decoupled two-leaf MSM isolation walls for the actual studio rooms.

In addition to the control room, I'd like to have space for a separate drum / live room and a vocal booth.

In addition to the control room, I'd like to have space for a separate drum / live room and a vocal booth. Do-able does anyone think?

Yes, absolutely, in 900 ft2. I have designed studios that meet your description and fit into half that space. A very tight fit, yes, but it can be done in 450 ft2. However, for what you are talking about, something in the region of 700 square feet would be a nice size.

Of course, all of the above assumes you have a suitable budget. Building a studio is not cheap. I'd suggest that you call around several local building contractors in your area, and ask for their rough estimate of how much they would charge to build a small house of around 700 ft2. Add about 20% to 30% on top of their estimate, and you'll have a rough idea of what it will cost you to build a studio that size. I have no idea where you live, since you didn't follow the forum rules, but for most places on this planet you should be thinking about upwards of US$ 100 per square foot, and it might be as much as US$ 500 per square foot in some places.

- Stuart -

[Soundman2020]

Thread test...

[markbirkett]

Dear Stuart,

Many thanks for all your considered input. I didn't realise you'd answered my post. Does this site inform you via email automatically if someone posts an answer?

I'm in Manchester England.

I am torn between pursuing my current room (in my latest post at http://www.johnlsayers.com/phpBB2/viewt ... =1&t=20387) and designing from scratch. Both options seem rather fraught!

I was genuinely surprised that you don't seem to hold much confidence in "ideal room ratios".

(I've read the forum rules since.. thanks for pointing that out!)

Thanks again,

Mark

[Soundman2020]

(I've read the forum rules since.. thanks for pointing that out!)

You might want to read them again! Especially the one in large blue letters, about a third of the way down the page...

Does this site inform you via email automatically if someone posts an answer?

Yes it does. It sends an e-mail automatically, provided that the "Notify me when a reply is posted" box is ticked (just below the box where you type your post). If you are not getting the e-mails, check your e-mail filters. It might be getting marked as spam incorrectly.

I was genuinely surprised that you don't seem to hold much confidence in "ideal room ratios".

I did not say that. I think you didn't read my reply very well. I said there is no such thing as one single "golden" ratio that is better than any other. Rather, there is a range of "good" ratios (inside the Bolt area, mostly) and another range of "bad" ratios.

Modes are a fact of life. Having a fantastic ratio will not make your room magically perfect, or even necessarily good. It will have modes, just like all other rooms. The only difference is that for good ratios, the modes are spread around evenly in the frequency domain: not too far apart, and without adjacent modes being too close together either. And since we are talking about small rooms here (acoustically small), the modes will ALWAYS be a problem, regardless of whether or not your ratio is excellent. Therefore you WILL need abundant bass trapping to help get your modes under control. That goes without saying. I would much rather mix in a room that has a poor ratio but excellent bass trapping, versus a room that has a "perfect" Sepmeyer #1 ratio, but non bass trapping. The former would be a much more even, stable, usable room than the latter.

Modes and ratios are just one of very many parameters that a studio designer takes into account when designing a control room, and frankly, not necessarily the most important, either. Many first time studio builders give way too much priority to room ratios, when room volume is arguably even more important. They shrink their tiny rooms down to even smaller sizes in a silly attempt to hit a "perfect" ratio, when in reality all they succeeded in doing is to reduce the total volume of the room to a point where it is no loner even viable. Room volume, symmetry, overall layout, geometry, isolation, and treatment are more important than "golden ratios", in my opinion and experience. As long as the ratio is far from the "bad" ones, and meets the critical equations for control rooms, that's all I'm really worried about. Modes can be dealt with in any of several ways, and even with sufficient porous absorber bass trapping they can be brought under control. Ratios are interesting, and useful to a certain extent, but over-emphasized by newbie builders.

The ratio you gave (1 : 1.59 : 2.09) is not very good. It is not close to any of the really good ones, even though it is inside the Bolt area. And it certainly is not a "golden" ratio. Where did you get it from?

You also did not clarify if you are talking about a live room, or a control room. If it is a live room, then modal behavior and room rations aren't a big deal anyway. If it is a control room, then that makes a bit more sense, but I still would never design a room whose length is within 10% of twice the height...

I am torn between pursuing my current room (in my latest post at...

I'll take a look at that over the weekend, but please do check the forum rules again...

- Stuart -

[markbirkett]

Thanks for the additional advice Stuart. I've re-read the forum rules and the only bits I think I've missed are to add my location (Manchester, England) and to state what my room is primarily for (mostly mixing so needs to be designed around trusting what's 'on the tape').

I'm still somewhat confused though. On the one hand you're saying that Bolt's ratios are overrated; on the other you're saying that some rooms are hopeless. In the end, I need to figure out whether my current room is worth investing money into or not. If so, I' d do it; if not, I'd build a studio from scratch. The former is obviously the preferred option!

As per my other recent post, attached are the dimensions of my current room. And what I'm trying to figure out is whether some form of bass trapping can be employed that doesn't result in me losing all the workable space, yet still get as close to a flat frequency response as possible.

[Soundman2020]

On the one hand you're saying that Bolt's ratios are overrated; on the other you're saying that some rooms are hopeless.

I don't see any contradiction there at all! I didn't say that Bolt's ratios are overrated: I said that prioritizing ratios over other factors is a common mistake. And yes, I also said that some rooms are hopeless. A perfect cube measuring 8 feet on each side, for example, would be pretty useless. On the other hand, a perfect cube measuring 38 feet on each side, would be entirely usable, and would make a great room. Terrible ratio, fantastic room. But a sphere or cylinder of pretty much any size would be unusable. And likewise, a room measuring 7'4" x 6' x 5'3" would be absolutely hopeless, no matter what you do to it, even though it perfectly hits Sepmeyer's first ratio, which is arguably considered to be the best of all. Fantastic ratio, terrible room.

It's not about ratios per se: It is about dimensions, volume, ratios, treatment, materials, furniture, gear, people, and how all of those compare to the wavelengths in question.

Studio designers do take ratios into account yes. The smaller the room, the more we take them into account. For large rooms, not so much. Once the room is big enough for there to be a statistically valid reverberant field across the entire spectrum of interest, then there is zero point in looking at ratios at all, since they are meaningless at that point. Total volume, longest free path, shape, and treatment are all extremely important factors that we take into account when designing rooms. Depending on the specific room, they are usually far more important than the ratio.

This is not mysticism on the one hand, nor is it rocket science on the other hand. It is simply a matter of understanding and applying the basic principles and equations of acoustics, and judging how the room shape and size affect acoustic response.

In the end, I need to figure out whether my current room is worth investing money into or not. If so, I' d do it; if not, I'd build a studio from scratch.

Dimensions: 2.66 x 2.33 x 2.18

The room ratio for that is 1 : 1.06 : 1.21 That is far outside the Bolt area, and fails one of the three "Critical tests" that the BBC uses to determine the viability of a room. The volume is 13m3, whereas the generally accepted "minimum" is 40 m3. The floor area is 6m2, whereas the ITU, EBU, AES and other specs all consider roughly 20m2 to be the minimum. The ceiling is also extremely low. There is no modal support at all below 65 Hz, an the Schroeder frequency for that room is way up at 184 Hz. In other words, all of the major modal issues are right smack in the middle of the most critical part of the spectrum, and below that, the room will simply be a "balloon" that pumps and breathes along with any tone that you happen to play.

This is not a happy situation at all.

You also have the room set up sideways, although it doesn't make a huge difference in this case. Rooms should be set up such that the speaker fires down the longer dimension, not the shorter dimension, but given that there isn't much difference in those two anyway, it's probably a moot point. with a room that size, you are pretty much forced to put the mix position in the geometric center of the room, which is the worst possible point, from the modal point of view. In addition, you show your speakers set up on top of the desk and your sub under the desk, with the desk pushed up tight against the wall. I do realize that you have no choice in such a small room, but that's a lousy setup: you will have severe comb filtering from the desk reflections, and an unwanted dip-and-boost in the mid-range, plus possible resonant issues from the air trapped under the desk.

That's a large number of negatives, and no positives so far!

You COULD put superchunks in all four vertical corners plus at least four horizontal corners, but the room isn't big enough for that, and one of them would completely cover the door, which is in a poor location (room corner). To deal with the modal issues, you'd need to make your superchunks at least 90cm on each side, which basically means that they would fill the entire room. Then you would need 20cm of porous absorption on the rear wall, plus 15cm absorption panels between the speakers and the front wall, plus 15cm absorption panels on the side walls (first reflection points), plus a 20cm thick cloud hung at an angle of at least 16°. Which means the cloud would be hanging in front of your face, and you'd have no room to move around at all. The room would sound absolutely dead. Uncomfortably so. There would be no way to change that, since anything you did to put life back in it would also necessarily create early reflections.

And finally, there's the issue of symmetry: your rack gear will create a very large upset in room symmetry, simple because it takes up a substantial volume of the room just by being there. Yes, I realize you have no other pace to put it, but it's going to screw up your sound stage and stereo imaging if you leave it where it is.

That's my rough assessment. I very much doubt that you could make that room usable as a quality listening room or control room. There is just too much going against it, and nothing going for it. I really can't see any saving grace at all.

Questions: Could you move two of the walls to make it considerably wider and longer? Could you take out the floor slab, dig down deeper, to make it higher? Could you take out the ceiling / floor above you, and move it up half a meter? If the answer to those is "no", then I don't see that room as being a viable option for you. It's just too small. It might be usable as an amp isolation booth, but that's about it. The single biggest factor, in my opinion, is the extremely low ceiling.

So that's my US$ 0.02, for what it's worth. Sadly, I don't see any future for that room. I think your best bet would be to go with your "Plan B", to build a purpose-designed studio from scratch. With a ground-up build, you can design it specifically to be the best possible for your needs, with none of the restrictions imposed by that tiny room. As long as your budget is sufficient, and you have enough space, then you could have a great studio.

To my mind, investing money in that room is only going to make it mediocre at best, and even that is questionable. Your money would be far better spent on getting a studio properly designed and built, from scratch.


- Stuart -