John Sayers' Recording Studio Design Forum Archive

Hi, long time lurker here but infrequent poster! I'm seeking a bit of peer review of a studio design for an extant building in south Wales.

The building is a mish-mash of building techniques, and was originally built in 1910 as a single story social club for the church next door. A second story was added an unknown time later. The main envelope of the the building is an example of an early cavity wall. One of the limiting factors for the studio design is that the external wythe of bricks in the cavity wall can't be properly airtight sealed. The original build quality is best described as shonky. The studio will be on the ground floor.

The biggest noise issues are sound ingress from the church and YMCA either side of me – cars, people, church bells etc. The building is detached, and I have the whole building, so internal neighbour problems are not an issue. Sound proofing is important, but extreme levels are not required.

Booth 1 will have extra layers of sheet material as it will be the area for loud/quiet instruments needing extra sound isolation when recording. 50-60 db attenuation would be desirable if possible.

Booth 2 cannot be sound proofed to drummer levels as there are multiple small air gap problems through the joist/brick wall area that are not properly sealable. There are also very large 8ft x 4ft timber windows and 6ft x 2ft timber sash windows in this area, rendering extreme sound isolation harder and more expensive to achieve

I am proposing building 2x4 stud frame walls with at least an inch air gap between the new stud wall and the existing brick. The control room and booths will be self-supporting, avoiding the need to tie them into the brick wall boundary. The surface of the brick walls has already been rough rendered in 3.5NHL lime mortar to seal the brick surface.

I do mix work and mostly acoustic ensemble recording, frequently on location. The studio will be for post production, overdubbling and small ensemble recording. As resources become available, the other rooms will become available as additional recording areas.

I've already done quite a lot of remedial work, and know the structure, issues and condition of the original building quite well. I am now ready to build some of the stud walls for the studio area. The studio build has to be done in stages to to resource limitations.

After considering issues to do with the building condition, tax, regulations, budget, scheduling, etc, I've come up with the following layout. There has been much research and many design iterations, but I believe this layout represents a good compromise between all the competing, conflicting design parameters.

Nothing in the building is square and the the Sketchup diagrams have been simplified to a degree for ease of visualisation.

External view: Internal view Plan view Details including internal dimensions

Hi there "Leland2", and Welcome to the forum!

Wow! That's an excellent first post: All the pertinent info is in there, clearly and concisely, along with a good SketchUp model that has obviously taken a LOT of work to prepare. I wish all new forum members would do their first posts like yours!

The biggest noise issues are sound ingress from the church and YMCA either side of me – cars, people, church bells etc.

Ouch! Have you measured all of those, to see how loud they are and figure out how much isolation you need? Church bells can be loud... so can the YMCA. You really should measure the levels, so you can plan the isolation effectively.

OK, on to your issues.

If you can't do anything to seal up your existing outer leaf due to structural / ventilation / access issues, and you need good isolation, then you are probably in one of those situations where three-leaf construction is a valid option. I would suggest that you consider modifying your design to make it three-leaf in those places where the outside brick walls can't be sealed. That's not necessary on the interior isolation wall, which can still be two-leaf, but it would probably be the best option for the others. Yes, you will lose a little space there, but you seem to have enough space that it is possible to do that.

Next, for your control room:

- There's no need to have a non-functional door for symmetry at the rear right of the room. Symmetry is critical at the front of the room, yes, but not so much in the rear. The rear wall is a key place for bass trapping, so losing such a large area for a door that isn't needed, is a problem. You can skip that.

- The other rear door should then go more towards the middle of the rear wall, because the corners are the best places for bass trapping. Leave them free for that, with plenty of space going out from the corners for that. 36" along each wall is good, more is better.

- The concave wedge shape of the rear wall is not optimal. It will tend to exaggerate the SBIR problem coming from that wall, since concave walls do tend to focus sound, and that angle looks like it would focus it at the mix position... not good. So either leave the rear wall flat, or make it convex (partly or completely). Convex would help a bit to disperse SBIR, and perhaps even slightly reduce some modal issues. As I said, you could do it just partially, which would be easier: In other words, make the corners 90°, then have the middle section as a concave wedge. Or you could make the wall itself flat, then just build a hefty wedge-shaped structure in the middle, to help with the above. That would be easier for construction, since non-square corners are hard to do.


Booths:

There's no sight lines form the CR into Booth 1: I would suggest putting a window in that wall. It's important for the engineer and musicians to be able to see each other clearly during mixing sessions, and having more glass between rooms helps to make the entire studio look more spacious, open, and airy.

Consider using sliding glass doors for access into the booths: Both for the above reasons (visibility) and also for the practical reason that they don't take up any space in the room itself, by needing a "sweep" area that they can swing into when opened. For a small booth, when you need to set up instruments, equipment, music stands, cables, etc. as well as people, it can be a real problem to do that when you also have to leave a many square feet of floor unoccupied, just so the door can open. Sliding glass doors have a lot going for them...

HVAC.

I don't see any provision for your HVAC system in there. I do realize that this is just a rough floor plan at present, to get the basic layouts right, but HVAC is a big issue in studios, so if you have not considered that yet, now would be a good time. The ducting and silencers are large, and eat into the room space, so it's important to take that into consideration at this early point in the design.

There's probably other items that can be improved, but I'm out of time for now....

- Stuart -

Thank you soundman2020!

Your points are well made. re the issues you raise:

Good point re noise measurements. I did do an ad hoc noise survey a while ago, and the average levels are pretty low for the most part - in normal conditions, internally, it's too low for my SPL meter to make a reading. When the church/YMCA/whatever has a function, the average is still low but there are spikes from people, cars, doors etc which a simple SPL meter reading doesn't really reflect.

The control room entry door was put on the side as I prefer to have the mix client able to sit behind the mix position on the centre axis of the room. This means the control room couch would be nearer the back along the room centre line and preventing easy door ingress for a rear door. I've left 18" of clearance in the back wall to door frame dimension for trapping in the corners.

The control room dimensions and shape were forumulated to get as close as possible to minimum desirable area and volume -200ft2 and 2000ft3. In this current design, the room is slightly undersized at 191ft2, volume is 2100ft3. The splay in the wall is 12 degrees, as I'm going for an RFZ type approach. I understand that there may be a focusing effect from the back wall design, but the design allows a small addition (12ft2) to the surface area compared to a straight back wall. I've seen the shape used by Roger D'Arcy in his book. Of course, the back wall will be treated with absorbers diffusors etc not detailed in these drawings.

Re sightlines - there didn't seem anyway to get a window into Booth 1 without messing the symmetry of the mix room up and introducing reflection points in undesirable places. There will be a window in the doors to booth 1. Not ideal, but I prefer to compromise in favour of mix room symmetry.

The issue with poor sightlines seems intractable given the area available and will have to be ameliorated with mirrors and video. Again, not ideal, but I can't see any way of making better sightlines without compromising either the control room area or the sound isolation.

The lack of access to Booth 2 from the contol room bothers me - so turning the small window in the front of the control room between the speakersto a small door is highly desirable. Of course, this will cause problems with the control room layout, particularly mixer placement (I have a medium sized DDA desk). I was unsure about having a door/window in this wall anyway from the point of view of monitor placement.

Sliding doors would be desirable, but my understanding is that the sound isolation using them is very poor. Any further info as to good designs for them would be welcome.

HVAC ducting will be in the gap between the original joists above the booths/control room, which will have its own post.. I have to do a lot more reading on this first!

Thank you for your time, effort and input!

The control room entry door was put on the side as I prefer to have the mix client able to sit behind the mix position on the centre axis of the room.

That is, indeed, a common way of setting up a control room! In fact, most of the rooms I design do have client couches at the rear... and where there is also a rear door, just move the couch forward a bit, so there's space behind it to get past.

Take a look at this one, for example: http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=2047. In one of the smaller photos you can see the space behind the couch, and the door in the rear. In that case, the door could not go anywhere else, as the structure of the rooms was already fixed when I came on board to the project, but even so, there's a large space behind the couch, to allow circulation.

Here's another case : http://www.johnlsayers.com/phpBB2/viewt ... 7&start=30 . In that one, there's no door at all on the rear wall, but the couch is still set far enough away from the rear wall treatment to allow circulation.

It isn't just about people circulating, either: it's about acoustics. Up against the rear wall is actually a terrible place, acoustically, in most studios. A few feet further forward is much better.

I've left 18" of clearance in the back wall to door frame dimension for trapping in the corners.

18" will not be enough. Even a small superchunk is 24" wide, and a more normal size superchunk is 36".

In this current design, the room is slightly undersized at 191ft2, volume is 2100ft3.

The volume is fine: the area is a bit small, but still pretty good. The "minimum" recommended area is actually 215 ft2, not 200, but you are still good with 191. I have done quite a few studios smaller than that, successfully.

The splay in the wall is 12 degrees, as I'm going for an RFZ type approach.

You seem to have misunderstood two entirely different concepts: the 12° splay is meant for flutter echo, not RFZ. 12° is way to small for RFZ. Typically, it is 30° for the speaker soffits, then coming down to maybe 16° or so for the wings. Try ray-tracing, and you'll soon see that 12° is way, way short of the angle you need for RFZ style rooms.

I understand that there may be a focusing effect from the back wall design,

Yes, but you missed the even bigger point: it's not just focusing that I'm talking about, but SBIR. It's already going to be a big problem in your room, without making it bigger like that. If you don't do something to the rear wall, you are going to have a rather major SBIR issue.

but the design allows a small addition (12ft2) to the surface area compared to a straight back wall.

Yes, but if that were one of my rooms, I would sacrifice that small space in favor of better acoustics. You could easily gain that space back in other ways. if you really do want it.

Of course, the back wall will be treated with absorbers diffusors etc not detailed in these drawings.

Your room is borderline big enough for numeric-series diffusers on the rear wall. I can't see you being able to get the minimum recommended distance needed between your head and the front surface of any diffusers you could have back there. Perhaps, but it's going to be right on the edge.

Re sightlines - there didn't seem anyway to get a window into Booth 1 without messing the symmetry of the mix room up and introducing reflection points in undesirable places

A wall is a reflection point, just as much as a window! I don't follow your argument. Besides, if you are doing an RFZ concept, as you say, then there will not be ANY reflection points... you would just incorporate your window into that, ais part of the RFZ design. It's not a problem. I have done several studios designs with windows or even sliding glass doors on the side walls, for good sight-lines between rooms. Far better than mirrors or video screens.

There will be a window in the doors to booth 1. Not ideal, but I prefer to compromise in favour of mix room symmetry.

I don't follow your reasoning: you already have mix room symmetry: Why would replacing the hinged doors with sliding doors alter that? In what way do you think sliding doors would change the CR symmetry? In any case, the doors for the CR are well behind your ears, way back in the rear half of the room, where symmetry is not as important as the front. It's only the front half where symmetry is critical. Behind that, it's nice if you can get it, but not "life or death" to the studio.

Again, not ideal, but I can't see any way of making better sightlines without compromising either the control room area or the sound isolation.

Once again, I'm not following your argument: Why would putting a window in a wall "compromise the sound isolation"? Glass has much higher density than drywall, so it is entirely possible to get excellent isolation while still having windows. Take a loo around the forum, and also photos of high.end studios: you see glass everywhere. Windows do not reduce isolation if designed correctly, and neither do they create problems with symmetry.

Sliding doors would be desirable, but my understanding is that the sound isolation using them is very poor. Any further info as to good designs for them would be welcome.

Take a look here: http://www.johnlsayers.com/ Those are rooms designed by John Sayers himself. See how many of those you can find where he used sliding glass doors...

Here's another case, in a small studio I designed a few years ago: Two views there: one for the CR to the booth, the other from the booth back to the CR. This is a drum TEACHING studio. There are often TWO drum kits going full bore in the CR, while there's a vocalist or instrument in the iso booth. And there's just a pair of sliding glass doors in between.

How much isolation do you need between the CR and iso booths, in decibels? That's what will determine the door and window plan. How much isolation do you need between the studio and the outside world, in decibels? That's what will determine the wall, ceiling, HVAC and electrical plan

It seems to be that you are not getting your information from good sources. You are worried about things that are not really that important, or that don't actually matter at all, and you are missing some of the things that are important. I realize that you have a lot of time invested in this layout already, and you are not inclined to change it, but there are several ways that it can be improved, and the result would be better than what you have now.

- Stuart -

Thank you for your reply - I particularly enjoyed its truculent delivery! But perhaps it's too detailed for the stage I'm at right now

I'm really just looking at concepts for the space layout at this point. Some of the criteria I have to satisfy with the design are not acoustic issues and unfortunately may have precedence over acoustics. I would like to fit two live areas and a control room into a space that's probably too small for such rooms to be a comfortable size.

The design at the moment is only of the rough layout. It would seem precipitate to draw in acoustic treatments, flush mount areas or HVAC at this point. The wall cross sections are in the design to give an idea of resulting areas. 20-30db of low frequency atttenuation (kick drum range) between live room 1 and the other rooms is desired. I'm aware that's not a particularly impressive amount, but I can work with it. If I can get more without an exponential increase in cost or complexity, that would of course be good!

The splay in the walls is as much to do with efficient use of the space as much as flutter echo or RFZ considerations. The main partition wall to create the passageway to the other rooms defines an angle of 12-14 degrees anyway. The angles necessary for RFZ would come from flush mounting of the monitors. I should have been clearer about that. I have also been contemplating Newall style non-environment designs, which would have a different layout of acoustic treatments. Hence that level of detail is not in the diagrams at this point.

When you say SBIR is a big problem with the design, could you give me some idea of why it is particularly problematic with this particular design? How would it manifest? Might you possibly point me in the direction of any literature examining this? There are succesful studios with similar splays – Phoenixsound in Pinewood, UK being one (a Roger D'Arcy design I think)

My reluctance to use a lot of glass stems from these concerns:
Suitable laminate glass being much more expensive than wall sheeting materials.
It is more complex to build a succesful window (or door) structure than a plain wall and takes more time, skill and money to do so. I suspect this is why windows (and doors) seem to be the weak point in many of the studios I've worked in. There's nothing wrong with glass as a material in itself, as you point out.
Windows take up space where absorbers or other acoustic treatments could go, though this of course would be incorporated into the design.

I'm aware of the sightlines issue. I'm having diffculty reconciling the opposing requirements. Hence the suboptimal sightlines in this layout idea - it seemed the least worst compromise. I have a very limited budget at the moment but need to create a heatable area by the onset of winter - this has more to do with hyperthermia than acoustics (joke)...

I'm open to other ways to divide the space, so any ideas would be most welcome. I've spent a lot of time over the last twenty years working as an recording engineer on location in suboptimal environments, so my expectations are low. So long as the design is better than working in an 8'x16' garage, I'm ahead...

If anyone is interested in having a go, here's a link to a simplified sketchup model of the building:
http://www.mediafire.com/file/b43h3h9wk ... m.skp/file

A totally new design following advice on opening up blocked doors in the building. Booth 1 would be added in after extensive building renovations and hence would have to happen much later, if time and budget allows. The control room and booth 2 have no external complications to be addressed and could be started any time.