John Sayers' Recording Studio Design Forum Archive

Hey guys stumbled upon the site doing some research for a fantasy recording studio that I'm trying to persue(everyone and their mom right lol)

Anyways I started out looking for a new spot to rent to jam and it turned into why not go for a studio of our own. Long story short I rounded up quite a few people who are into it as well as a small radio station on the real air waves

So I don't have db levels for how loud we normally get but I'd say "too damn loud" or so I've been told lol. full stacks and drums sort of thing. Will try and get some readings at some point.

I found a spot I quite like(rent per month, size, location, shower, kitchen, bathroom, and laundry.) It's got neighbors on both sides but they are buisnesses that probably takeoff after a certain time/day. It's basically a big rectangle with a door at either end one goes outside the other goes to the kitchen/bathroom area. 21 feet wide 40 feet long I think don't quote me on that and high ceilings maybe 13 feet.

When thinking about added walls to iso the sounds inside I ran into a few things that I was wondering about. If I built a liveroom inside this room as big as possible but with a space or hall to provide access to the kitchen/bathroom without walking thru the liveroom What would be the best way to avoid making a third leaf problem?

I was thinking of a 4.5 or 5 foot wide space to walk to the back of the room thru but if I leave the exsisting double leaf wall and build another wall of any construction I'd still have two air spaces and a third leaf effect, right?

I'm having trouble imagining that the solution is exposing the exsisting walls guts by removing the drywall and adding rockwool then building the liveroom wall and the hallway would be studs and rockwool on either side with like some fancy looking fabric to cover it up.

At what point does the distance between two seperate air spaces negate the triple leaf effect?

Budget can be anything cuz this is hypothetical at this point but reasonable for purposes of pitching to others about cost and feasiblity.

Cheers & Thanks for the site and info

Hi there "SunkenCity", and Welcome!

It's got neighbors on both sides

What's above you and below you?

When thinking about added walls to iso the sounds inside I ran into a few things that I was wondering about.

Your control room is unworkable, and would be unusable. There are several basic, critical key points that you neeed to take into account for a control room:

- It must be symmetrical: the left half absolutely has to be the mirror image of the right half.
- It needs a minimum of 210 square feet floor area. It is possible to go a bit smaller, but the smaller you make it, the harder (and more expensive) it will be to treat it, and the poorer the final acoustics will be.
- Corners are sacred: they are needed for treatment. Don't eve put a door or window in a corner, nor anything ease that interferes with that treatment.
- Modal response is an issue. It is important to have a set of dimensions for your room that minimize the modal issues. Long thin rooms will not have usable modal response.
- And a few others too, but those are the biggies that your current control room plan is violating.

If I built a liveroom inside this room as big as possible but with a space or hall to provide access to the kitchen/bathroom without walking thru the liveroom What would be the best way to avoid making a third leaf problem?

Do it like this:
That's the concept. You can extrapolate from there to your own situation.

if I leave the exsisting double leaf wall and build another wall of any construction I'd still have two air spaces and a third leaf effect, right?

Yes, but it's not an issue in your case. The air gap is so wide that the MSM resonant frequency would be way, way down low. Too low to be a problem.

At what point does the distance between two seperate air spaces negate the triple leaf effect?

At the point where the f+ resonant frequency of the MSMSM system is significantly more than an octave below the lowest frequency that you need to isolate, and the remaining parts equations in the set that you need to solve, show that you are getting enough isolation in all parts of the spectrum.

That sounds a bit like a cop-out, I know, but it's the technical truth, and real hard to put into simpler words.

Basically, as you already know, the wall is a resonant system: that's why it works to isolate. At the resonant frequency it does NOT isolate, but at all frequencies more than one octave higher, it does. So as long as you can get the frequency low enough, you can isolate whatever frequency you want. The way you do that, is by adjusting the mass on each of your leaves (surface density) and the size of the air gap between the leaves. Bigger gap=lower frequency. More mass=lower frequency. The problem with 3-leaf walls comes from having small-ish gaps (just a couple of inches). That puts the resonant frequency up too high, well inside the audible spectrum. But when you are talking about several feet, that pushes the resonant frequency down, down, down.

Budget can be anything cuz this is hypothetical at this point but reasonable for purposes of pitching to others about cost and feasiblity.

It is perfectly feasible. I designed a studio for a company in Wales a few years back that had a similar problem: the needed access behind the control room in order to get to the bathrooms, offices, and main entrance, without having to walk through the control room or live room every time. So there's a long, narrow corridor in there, similar to what you need to do. It can be done.

- Stuart -

Soundman2020 wrote:Hi there "SunkenCity", and Welcome!

It's got neighbors on both sides

What's above you and below you?

When thinking about added walls to iso the sounds inside I ran into a few things that I was wondering about.

Your control room is unworkable, and would be unusable. There are several basic, critical key points that you neeed to take into account for a control room:

- It must be symmetrical: the left half absolutely has to be the mirror image of the right half.
- It needs a minimum of 210 square feet floor area. It is possible to go a bit smaller, but the smaller you make it, the harder (and more expensive) it will be to treat it, and the poorer the final acoustics will be.
- Corners are sacred: they are needed for treatment. Don't eve put a door or window in a corner, nor anything ease that interferes with that treatment.
- Modal response is an issue. It is important to have a set of dimensions for your room that minimize the modal issues. Long thin rooms will not have usable modal response.
- And a few others too, but those are the biggies that your current control room plan is violating.

If I built a liveroom inside this room as big as possible but with a space or hall to provide access to the kitchen/bathroom without walking thru the liveroom What would be the best way to avoid making a third leaf problem?

Do it like this:

MSM-two-leaf-WallChunk-conventional-NOT-inside-out--three-room--with-corridor--S04.png

That's the concept. You can extrapolate from there to your own situation.

if I leave the exsisting double leaf wall and build another wall of any construction I'd still have two air spaces and a third leaf effect, right?

Yes, but it's not an issue in your case. The air gap is so wide that the MSM resonant frequency would be way, way down low. Too low to be a problem.

At what point does the distance between two seperate air spaces negate the triple leaf effect?

At the point where the f+ resonant frequency of the MSMSM system is significantly more than an octave below the lowest frequency that you need to isolate, and the remaining parts equations in the set that you need to solve, show that you are getting enough isolation in all parts of the spectrum.

That sounds a bit like a cop-out, I know, but it's the technical truth, and real hard to put into simpler words.

Basically, as you already know, the wall is a resonant system: that's why it works to isolate. At the resonant frequency it does NOT isolate, but at all frequencies more than one octave higher, it does. So as long as you can get the frequency low enough, you can isolate whatever frequency you want. The way you do that, is by adjusting the mass on each of your leaves (surface density) and the size of the air gap between the leaves. Bigger gap=lower frequency. More mass=lower frequency. The problem with 3-leaf walls comes from having small-ish gaps (just a couple of inches). That puts the resonant frequency up too high, well inside the audible spectrum. But when you are talking about several feet, that pushes the resonant frequency down, down, down.

Budget can be anything cuz this is hypothetical at this point but reasonable for purposes of pitching to others about cost and feasiblity.

It is perfectly feasible. I designed a studio for a company in Wales a few years back that had a similar problem: the needed access behind the control room in order to get to the bathrooms, offices, and main entrance, without having to walk through the control room or live room every time. So there's a long, narrow corridor in there, similar to what you need to do. It can be done.

- Stuart -

Wow this is a great response!! Thanks For taking the time to write all that out.

Nothing above me and no basement.

Modal response? Links to a good read? Where could I find some set dimensions?

If I change the dimensions of the control room:

Is it possible to have the face of it at a angle like that? Is it even a good idea to have it at an angle like that?

Thanks for that image helps me visalize the make up of the walls better.

Nothing above me and no basement.

Great! So single story, slab-on-grade floor. Excellent.

Modal response? Links to a good read? Where could I find some set dimensions?

Modal response: That refers to the way a sound wave can "fit in" perfectly between walls, bouncing back on itself, and reinforcing itself, building up, getting louder, and "ringing". That happens for every tone where the wavelength happens to match the distance between two walls. Like this:

When that happens, the wave bounces back and forth between those walls, setting up a pattern of peaks and troughs in the room at fixed locations. Like this:
That is called a "standing wave" for obvious reasons. The wave does not actually stand still, though! It keeps on moving. It just creates pressure peaks and nulls in the room, so it SOUNDS like it is standing still, but in reality it isn't. Here's another way of looking at it, showing the pressure peaks and dips:
The top image is in 1 dimension, so you get a mental picture of how it works, and this one is in 2D, so you can see how the patterns form in the room, and how some places will have a different sound intensity from others for any given mode. In reality, it all happens in 3D, not 1D or 2D, and since there it can happen in all three directions at once, things get complicated:
On each trip around the room, the wave adds a bit more energy to itself, so it gets loud, fast. And after the tone stops, the mode carries on. So after you stop playing the note that caused that resonance, the resonance continues for a while, slowly dying away. In other words, the room carries on playing that note after you stopped! But for low frequencies, usually the very next note up the scale, or down the scale, does not have a mode associated with it, so it does not "ring". Meaning that some notes ring, while others don't. Not a happy situation.

It would be fine if every note on the scale had a mode or two associated with it, since the room would then sound the same for all notes, and that is indeed what happens for mid and high frequencies, where there are many dozens, or even hundreds, of modes for any given note. But as you go down the scale, they get fewer and further between, until at some point (referred to as the Schroeder frequency), there aren't enough modes to go around any more. You start finding notes that have no modes. And the lower down you go, the worse it gets, until at the very bottom end, there are no modes at all.

The problem occurs in small rooms, not so much in large rooms, simply because large rooms have large dimensions, and therefore many ways that a wave can bounce around. But small rooms don't. There's a limited number of modes. So one of your goals in designing a room is to find a set of dimensions that forces the modes to be spread out evenly, rather than concentrated in one or two points.

Here's an illustration that I just happened to have prepared earlier today, to show another member why his small room will not be able to sound like a large room (he refuses to believe me, but that's his problem, not mine! ).

Here's the predicted modal spread for his room, which measures 10 feet long by seven feet wide by seven feet high:
As you can see, there are no modes at all below about 50 Hz, and only 3 modes below 100 Hz. So as you play your bass guitar in there, each time you happen to hit one of those three notes, the room will sing along with you, loudly, and carry on singing after you stop playing that note, but for all the other notes it won't do that. Imagine how disconcerting it would be to play bass in there! Or electric guitar. Or keyboards. In fact, in that particular room, there is no real modal field below about 400 Hz, which is well up into the voice range, so even vocals and acoustic guitars would be affected.

On the other hand, here's the predicted modal response for a beautiful live room, which I'll call "studio B": That room measures 45 feet long by 35 wide by 23 high, and you can see that it has hundreds of possible modes, all across the low end of the spectrum, smoothly spread out. It has full modal support down to 45 Hz, and pretty decent response even below that, down to about 23 Hz (the first note that has no mode at all). So bass, drums, keyboards, guitars, vocals, and everything else will sound just fine in there, because there are plenty of modes, and they are smoothly spread out. That room is said to be among the best in the world for drums, and the modal spread data shows one o the reasons why.

So, when you design your rooms, you need to take into account the modal spread. To get good modal spread, the rooms need to be as large as possible, with ceilings as high as possible, and a good relationship between the dimensions, such that no two dimensions are mathematically related (such as being 7 feet wide and 7 feet high, for example, nor 7 and 14), and also not within 5% of being related. There are other rules as well, but you can play around on your own to find a good modal spread. Use one of these Room Ratio calculators to figure out the best dimensions for your room:
http://www.bobgolds.com/Mode/RoomModes.htm

http://amroc.andymel.eu/

Both of those are very good, and will help you to decide how best to build your room.

Is it possible to have the face of it at a angle like that? Is it even a good idea to have it at an angle like that?

The control room MUST be symmetrical. If not, your left ear won't hear the same acoustic response as your right ear, and you will subconsciously attempt to "fix" that in the mix... You might get it sounding perfectly balanced in your room, but it would sound lousy when played elsewhere, since no other place on earth would have the same imbalance as your room.

So you need to draw an imaginary line down the length of your room, splitting it in half, and the left half should be a mirror image of the right half. At least for the front part of the room (from your ears to the front wall), that's an absolute necessity. You can relax that rule a bit for hte part of the room behind your head, but for the front, symmetry is critical.

- Stuart -

Sorry It's been a while and I forgot to check in.

Thanks for that explanation, pictures and mode calculators.

How would you enter a room into that has a room within it?