Soundman2020 - Studio Design Forum

Hello All!

Sam here, I was a long time member of the John Sayers (RIP) forum. I received a ton of great advice and guidance from that wonderful group of people when I built my first studio over a decade ago (especially Stuart) I am hoping to get the same value and amazing advice here!

A little background on my project. I built my first studio in 2006-2008 in the basement of my town house. At the time I was young immature and impatient. My goal was to just get something up and running as quickly as possible because I was in a band and I had bands that wanted to record. Well, impatience doesn't really pay off when designing a functional studio. I was able to achieve a nice level of isolation, never had any complaints of noise from neighbors that were directly attached, so that was a success. However, HVAC was poor and people were really suffering in the very small (square) rooms I had built. The small live room was impossible to tame. I had so much reflection, flutter, and artifacting in my recordings I ended up resampling drums on almost every record I did there. Additionally, I put almost no thought into the control room area which was not treated well, and not symmetrical. All of these things were difficult to deal with, but as life caught up to me and my family started to grow, I abandoned the studio and moved into a larger house. That was 12 years ago.

About 3 years ago I setup a make shift space in the finished basement of my new house, which was ok. I got to set my console back up and get things sort of going for my own personal use but with several kids it was never easy to get clean takes on anything. My wife also didn't want my "biker friends" traipsing in and out of the house so it was a purely personal space. Sadly, last year we had a major storm here in the north east and my basement was flooded. I lost a lot of equipment and the only space I had is now ruined.

After a very honest conversation with my wife we agreed that after 12 years it was time to rebuild my studio. We really want to give the kids a place to explore their creative outlet, and I need a space to continue my passion (and maybe in a few years a nice side gig for me when I retire!). Armed with spousal approval, a healthy budget, clear goals, and patience, I am embarking on my second studio build.

What am I starting with:

Today we are in our forever home on a 1 acre lot in the suburbs. Due to township restrictions and the layout of my property, I can build an additional 500sf structure on my property in a rectangular orientation (roughly 1:2). It needs to sit on a setback line with one corner closest to the house reserved for a bathroom because of the pitch of the property and the requirement for the sewage line drop.

Based on the 500sf limitation and other factors (including spousal approval) it can be roughly 18-20 feet wide and 26-28 feet long. Longer than 28 feet will require me to do some regrading of the property which could get costly. Wider than 20 feet will start to encroach on the minimum distance it needs to be from the house to be considered an accessory structure (which is taxed differently). I think I can do 18-28 in the location and it would be just right at 504sf.

Luckily the roof can be up to 16' high at the peak, so I can reasonably get 12' vaulted ceilings throughout. Which means even rooms that are 11'x 13' could have 1500 cubic feet of space.

Requirements

Other considerations

Based on all of the above, I have come up with a few floor plans I like. Some prioritize the live room, some prioritize the mixing room, and one that balances both. Id like some general feedback on how I have approached this based on the one that is currently the most attractive to me. So here is the list of questions I would ask:

OK, so that is my first post. I hope I provided everything needed to get some meaningful feedback. My post has received little traction on johnlsayers forum, so maybe if I "follow the Stuart" I might get some love here.

Hi Sam, and WELCOME!

Wow! It's good to have you back again, and ready to build another place. I'm really glad you found your way over here.

And WOW! :shock:

That was an excellent first post. It covers all bases, and then some. This is a great example of how a first post SHOULD be done.

OK, I'll work my way through it slowly now, commenting as I go...

- Stuart -

First point: I made your thread "sticky" for a while, so others get to see a good way to do a first post...

- Stuart -

Soundman2020 wrote:Source of the post First point: I made your thread "sticky" for a while, so others get to see a good way to do a first post...

- Stuart -

Wow! Thanks, Stuart. Happy to be in contact again! I made some formatting edits, but looks like it needs approval. Appreciate any and all feedback.

General comments, mostly in the same order you wrote:

Sadly, last year we had a major storm here in the north east and my basement was flooded. I lost a lot of equipment and the only space I had is now ruined.

That must have been a major heartbreak! Real bummer, of the first order. I'm real sorry to hear that.

Armed with spousal approval, a healthy budget, clear goals, and patience, I am embarking on my second studio build.

Cool! So you are somewhat of a "sucker for punishment", as the saying goes! Ready to go another round with a heavyweight: "Studio Construction": But at least this time you know what you are in for,m and are much better prepared.

I can build an additional 500sf structure on my property in a rectangular orientation

500 ft2 is a really nice size for what is basically a 2-room studio, with some "service" space (bathroom, storage, etc). Assuming about 50-80 ft2 for service, and 200 for the CR (minimum recommended size), that leaves a good 200 ft2 for your LR. Not huge, but big enough for what you want, especially if you can have a high ceiling in there. This sounds like it can be a good studio.

- In order to maintain spousal approval, it must have a bathroom.

Absolutely! I always recommend that, whenever possible, for home studios. Wives don't take kindly to having strangers moving around the house, to use the facilities. In addition to the bathroom, I would also highly recommend a small kitchenette, for the same reason: If you want to warm a pizza, make coffee, grab a beer or coke, etc, then you don't want to have to go over to the house for that. So at least a place with a small bar fridge, microwave, some storage for mugs and plates, and a small sink. That can actually fit into a surprisingly small space while still being functional, and can be part of your entrance "lobby". It can also have some extra storage space, perhaps, for things like mic stands, instrument cases, unused drum stuff, etc. Plus a place for the mop, broom, and vacuum cleaner! don't forget those...

While I don't have exact readings because there is no structure to measure, I imagine stc of 60 is going to be a minimum requirement.

Careful with "STC"! Don't confuse that with real isolation, more technically referred to as "Transmission Loss". Here's an article I wrote about that, a while back, that explains the issue. Why STC is not a good way of measuring studio isolation.

You probably meant "60 dB isolation", and that's a reasonable goal. Not easy to get there, but possible. It's towards the high end of what you can expect to get, realistically, for a home studio. To put that in perspective, a typical house wall will get you maybe 25-to 30 dB of isolation. A tight-budget home studio should be able to get around 40 dB, with some care to detail. 50 dB is typically what a home studio or project studio will get, if there is a decent budget, and that is usually enough for average needs. 60 dB implies 1000 times better isolation (in terms of sound power) than the original "typical house wall", and subjectively levels outside will be about 1/8th of that. The relationship is simple: each time you change by 10 dB, that's a ten-times change in power level, and a two-times change in subjective listening sound level. Thus, going from 30 dB to 40 dB sounds about half as loud, going from 40 dB to 50 dB is about half as loud again (so 1/4 as loud as the original), and 60 dB is yet another "half as loud" factor, thus 1/8 as loud as the original house wall. That is pretty darn good, in reality, and will certainly silence the problem with your lawn-mowing neighbor. Combined with the 300 foot distance to his house, that should also get your drummer down to very quiet levels, probably inaudible, at his place. So it's a reasonable goal, and achievable with a good budget and very careful attention to detail in the design and the build.

Id like to prioritize having a control room that translates well and can accomadate both my audio equipment and my regular work setup.

Shouldn't be a problem. You have the space to do that, and you have the experience with your previous place to know what does NOT work!

The live room is very important to me, but it is also where I will have to make hard choices. This is where people will be, where we will write music and where my last studio really fell short. It was 10'x10'x7' and it sucked

Tiny, square, and low ceiling! I'm not surprised at all that it sucked. Your new one can have about twice the floor area (maybe more), twice the ceiling height, and won't be square, so it certainly can be much better.

If I have to sacrifice fitting a live band in the LR and only be able to record things in pieces when I want to isolate stuff, this is a sacrifice I am willing to make. It would be nice to find a balance between the 2 rooms.

While only two rooms will specifically be "studio" rooms, don't rule out the others! Bathroom, lobby, and even store room can all serve double-duty, for things that don't need isolation or mics. Eg, bass guitar player, keyboard player, electric guitar player.... they can all be sent out to those other rooms, with headphones, if space gets low in the main LR. Things like vocals and acoustic guitar can also be mic'd successfully in the CR, if necessary. It seems like Glenn already alerted you to this, but it is worth repeating here. Just remember to put patch bays in each of those other rooms, for emergency use. That includes patching for CCTV cameras and monitors as well (both directions). Musicians tend to play a lot "tighter" if they can all see each other, and also see the engineer. Ideally you want windows for that, but at a pinch you can do it reasonably well with CCTV.

- I need some storage. Any small closet to put a few tupperware bins of cables, microphones, computer parts, etc is necessary to fully move my office out of my house.

I can think of LOTS of places in your rough outline where you can have storage, that you probably haven't seen yet!

- Light. I desire natural light. I have been working in gloomy basements and corner offices with no windows for the better part of 20 years. I desire light and lots of it. That means windows. I don't care if they open, I just need to see nature and let the sun in

Not a problem! Studios can, indeed, have windows and natural light. When I'm designing places for clients, that¿s one of the big goals I try to aim for: an "airy" look, with as much glass as possible between rooms, and at least one room with windows to the outside. As you mentioned, I'd suggest that they should be non.operable (not opening), as that complicates the issue of isolation. It is a lot easier to get high levels of isolation with glass that is sealed in place! Here's one way to do that: site built windows for high isolation

- HVAC, I will be using a mitsubishi ducted minisplit system to condition the air throughout the space, paired with an aprilaire 8100 ERV. The combination can achieve 500CFM of air movement. I did some rough math for the space (18x28x12) * 6 air changes per hour / 60 = 600CFM. One of my questions below will actually be about the sizing of this system.

That setup can probably work for your new place. Good HVAC design should make it do-able. You don't need so much air in the storage room, for example, since it isn't a "habitable space". So you can have lower flow in there in order to have higher elsewhere. The bathroom doesn't need to be included in the HVAC conditioned space: it can have it's own separate ventilation fan. I have a system I use in some studios for using the bathroom as part of the overall system, without actually taking up any capacity....

I'll let you know about that, when the time comes....

- I have a health build budget, I think, of $50-75k USD.

Hmmm... It sounds a little on the low side, for a high-isolation four-room studio. Assuming 75k for 500 ft, that works out to about $ 150 per square foot. That might be do-able if the majority of the labor is free, and you choose your materials carefully. It's probably OK, but if you can squeeze out a few more dollars, that would definitely be a good idea.

I want a RFZ design in the control room and as close to a good ratio as I can get (i guess).

Yes! Absolutely! It's no secret that I'm a big fan of RFZ type rooms.

If I have to heavily treat the room anyway because of its size does one of these things matter more than the other?

In my opinion, RFZ with proper flush-mounted speakers ("soffit mounted"), is the best single things that anyone can do for any room. Flush mounting removes or greatly reduces most of the artifacts that arise from having a speaker inside the room, and RFZ creates the best possible acosutic response around the engineer. So RFZ should be your #1 priority. Room ratios are interesting, but nowhere near as big a thing as some people think. Here's an article I wrote about ratios and things a while back. It's rather long, but lays out pretty much all of the things you should be aware of: Modes, Room Ratios, and Schroeder

Also, if your room is not a perfect rectangle (and the room outline you show is not: it has six walls, not four, and two of them are angled, as well as the ceiling...), then ratios are really, really hard to figure out. The usual on-line room ration calculators only work for rooms with four mutually perpendicular walls, and parallel ceiling/floor, all with perfect 90° angles in all corners. If you angle just one of the walls, then those calculators no longer give accurate results. There are methods you can use to help estimate response of non-rectangular rooms, but accuracy is out the window. So there's no need to worry too much about ratios, as long as things are not square.

... More later, in 'part "B" '! I'm out of time right now.... Stay tuned for later....

- Stuart -

What a fantastic response! This is exactly the type of feedback I was hoping for. I will have some responses, but I will hold until part b so I don't ask things you are already preparing to answer.

Thank you!

Part "B"...

The room design I like is 16'x13'x9. This gets me into the 1:1.4:1.9 best ratio for louden territory.

It's a good, one yes... but is not applicable to your room, since it is not rectangular. Also, see the article I linked to in "Part A" on modes.

However, Im not really sure after reading several topics and articles how the mode relates to the RFZ design with splaying the walls etc. In my design below, I have the walls at 6 degrees for each side, totaling 12,

That's one way of getting an RFZ design, yes, but you can also get a good RFZ room without splaying any walls: Start with a rectangle (which makes your modal calculations simple, and allows you to choose a ratio, if you want to), then just build "soffits" in the front corners, with angled front faces.

With these angles, do I still need sofits or will cramming the monitors against the wall on my desk be enough?

Oh yes! Soffits are the key. If you have speakers on stands inside the room, then those speakers (and probably the stands too) are generating an entire text book worth of artifacts: Things like power imbalance, edge diffraction, SBIR, comb filtering, baffle step response issues, reflections, etc. That is simply because the speakers are in the room. If you take the speakers out of the room, then the artifacts go away! Gone! Disappeared! Or at the very least, greatly reduced. You do that by "flush mounting" (="soffit mounting") your speakers. If the speaker is mounted in the wall itself, with the speaker face flush with the wall, then the speaker is no longer in the room! It is in the wall. Hence, the artifacts from the "speaker-in-the-room" situation are gone.

In fact, you can't really have a true RFZ style design, if your speakers are on stands. Part of the RFZ concept has the speakers flush-mounted in angled wall sections.

Im not really sure what value sofits provide.

Mmmm... If I had to guess, I'd say about 50% of the entire acosutic response of your room! Maybe more. Soffits are the biggest single thing you can do to improve your room. Any room. That's my opinion, of course: Other designers might not share that, but if you look at the final acoustic response graphs of what can be achieved in rooms with RFZ type design, it is impressive.

c. Im also not sure how to balance room mode and RFZ design. Am I doing it right?

If you need to trade off in one direction or the other, then ALWAYS favor RFZ over modes. With one exception: If doing the RFZ concept would create a significant reduction in the total room volume, then don't. However, I've never come across a situation like that. It is possible to design RFZ soffits such that there is basically no reduction in room volume...

How far do the walls also need to be splayed,

Simple answer: They don't!

Splaying your walls reduces room volume, makes construction more complex (and more expensive), complicates acoustic prediction, and doesn't give you any real advantage. There are a few occasions where you might want to do it anyway, for one specific reason or another, but in general it isn't needed and doesn't give you any major advantage.

d. the windows at the back of the room, will they be problematic? This is the side the sun sets on, I really want the light to come in, but I also understand this will be my primary area for bass trapping.

There are ways for dealing with windows at the rear of the room, but I'm wondering if a different layout of the rooms might be a better option. I think it might be possible to do everything you want to do, with a different layout of the rooms. I'm not certain, as I haven't tried anything on paper, but just from looking at it, I think there might be a better way to lay it all out (while still keeping your bathroom in that corner, of course).

Entrance, I really only have one reasonable spot to put a door in this design.

Why? I guess you are talking about the main door into the entire building? What is the restriction on locating that door? How far can it move, reasonably? For example, could it go a few feet to the left or right, or must it be exactly where you show it?

f. The window to the live room, I plan to make modular diffusers/absorbers that I can strategically hang when mixing, any reason that even if this was a first reflection point I couldnt just cover it up with one of those when I go to mix mode? (I understand I still need to ray trace

If your design forces you to have to cover up something in normal operation of the studio, then I'd suggest changing the design so that isn't necessary! Design the entire studio layout such that there are no objectionable reflections at the mix position within the first 20ms. In fact, that is part of the RFZ concept: No reflections above -20db in the first 20ms after the direct sound. (At very worst case, -10db within 10ms) It should not be necessary to "kludge" things in a studio that size, to meet the criteria on some occasions. It should be designed-in to the basic room layout. With a very small room, that might be the only way, but you have enough space to be able to achieve that, I think.

g. Ceiling. Should I do a vaulted ceiling and follow the roof, or does it need to be a flat 9' height? More volume is better, but Im not sure if there is something I need to consider when detailing the rise and run of the ceiling.

For the Live Room: Definitely! Try to maximize height and volume: instruments (and musicians) do like height, to get the most "spacious", "airy" sound that they can. For the CR, the key issue is symmetry: If you can figure out a way to have the ceiling both vaulted and also symmetrical, then go for it!

a. Feels smaller than I'd like, but coming out of 10x10x7, especially now with 12' vaulted ceiling, I am hitting 1500 cubic feet of space and 156sqft of floor space. Is this workable for a live room? Will I hate life in there with a drummer and bass player?

I think it could be bigger. I think there are ways to lay out your building to maybe gain a few extra square feet in there, while at the same time improving the CR situation. Like I say, I haven't tried anything on paper: it's just a hunch. I think there might be a better way to organize things, and still hit all your key points.

b. do i need to splay the walls here? I know that any angle will help with reflection, but feels like I should prioritize square footage over angles.

In your case, I would go for the greatest room size. You need as much floor area (and volume) as possible, so do whatever ti takes to optimize that.

3. Generally speaking, how serious is the 6 changes per hour for fresh air?

ASHRAE (and many other places) recommend 4 as the minimum, 6 is OK, and 8 is better. Some rooms need even more. For example: bakeries, bars, clubs, cocktail lounges need 20 to 30 room changes per hour! Here's a page that will probably knock your socks off: https://www.engineeringtoolbox.com/air- ... d_867.html

I read on the EPA website that .35 changes per hour for a home is what is considered healthy.

Houses are not studios!

Houses are "leaky", in the sense that there are many other paths for air to get in and out, in addition to the HVAC path. Such as open doors and windows, cracks, gaps, holes, etc. Studios are sealed completely air-tight, twice over. Doors are always closed, windows don't even open.... It's a different situation.

Also, there's two very different concepts here that often get confused and muddle together. One is the total flow rate of the system: how much air you need to move through the room every hour, to ensure even mixing, good temperature distribution, proper humidity control, etc. The other is how much FRESH air you need to add to that, to keep people alive, and even more important, how much STALE air you need to remove in order to keep people alive.

Let's look at that second point, first: Many people assume that the reason for bringing in fresh air is to provide enough oxygen: that's partly true, but it's not the real reason. The REAL reason is that you need to get rid of the CO2! You exhale a large volume of CO2 with every breath, and it builds up fast in a sealed room. Since the concentration of CO2 in fresh air is very small (about 0.04%), you don't need to add a lot before the concentration gets up high. On the other hand, the concentration of oxygen is about 21%, so even if you use up a LOT of oxygen as you breath, there's still plenty there. You will die from CO2 poisoning long before you die from oxygen starvation, and CO2 rises very fast in sealed spaces, much faster than oxygen decreases. You pass out from CO2 poisoning long before you pass out from lack of oxygen. And way before that, at much lower CO2 concentrations, you start to feel bad, suffer headaches, nausea, vision problems, attention problems, ... way before your body even notices the slightly lower level of oxygen. You can die in a room that has plenty of oxygen available, if the CO2 level is high enough. You can live with only 15% oxygen in the room (6% points down from normal), but 6.04% CO2 (6% points up from normal) is not something you want to have in your room, if you plan to live.... :shock:

.... That will kill you very, very fast.

(In addition to the CO2 thing, there's also the issue of other nasty stuff emitted by people, including various body odors.... You REALLY want to move air fast, to get rid of that)

So firstly, you need to REMOVE enough CO2 (stale air) to keep people alive, and in order to do that, you need to provide enough fresh air to replace the stale air that you removed. You dump a certain amount of the room air overboard, and you bring in the same amount of fresh air to replace it. This has NOTHING AT ALL to do with the re-circulation rate (we'll get to that below...) This is just about moving CO2 out and oxygen in.

In addition to keeping people alive and happy, you ALSO want to move a much larger volume of air around the room (re-circulation) and through the room: to ensure that the fresh air comes in then mixes with the room air fast, and gets to the people fast, so that the concentration of both CO2 and oxygen stays about the same THROUGHOUT the room. Consider this: If you sit still in one place and there is no air movement at all in the room, then you create a "bubble" of atmosphere around you that is high in CO2, low in oxygen, high in humidity, high in temperature, etc... while over in the corner of the room, it is cooler, dryer, and with a property balanced mix of CO2 and O2.

So, firstly you need to ensure that you are bringing in enough fresh air and removing enough stale air to keep everyone alive and comfortable. This is also sometimes called "make-up" air in HVAC terminology. And obviously, you need ducts in your HVAC system to do this. First, a duct that dumps some of the room air into the outside world, and ANOTHER duct that brings in the same amount of fresh air from the outside world.

That's the first part. That is based on occupancy: how many people there will be inside the room. It is not related to room size: just the number of living, breathing bodies in the room, that you want to keep living and breathing.

Then theirs the SECOND part, which is recirculating air through the room to ensure good mixing, so that temperature, humidity, CO2, and O2 are pretty much constant throughout the room, with no "pockets" of hot, humid, "bad" air, nor of cold, dry, "good" air. There's also the issue of "speed". Not in the sense of how fast the air comes out the HVAC registers, but rather in terms of how fast it gets to you.

Think of it this way: if you are (hypothetically) sitting in the middle of a room, and the HVAC register is in one of the walls, then it takes a certain amount if time before the air arrives at your location. So, let's say you arrive at your room in the late afternoon, after a real scorcher, and it is hot and humid inside the room. So you sit down at your console, turn on the HVAC, and wait. If the HVAC system is circulating air at the very low rate of one room change per hour, and you are in the middle of the room, then it will be HALF AN HOUR before you start to feel the effects. Half an hour, because the air is moving at 1 change per hour, and you are in the middle. If you were up against the far wall, opposite the HVAC register, it would take an entire hour before you start feeling the effects! :shock:

On the other hand, if you are circulating air at the rate of 6 changes per hour, that is one change every ten minutes so you start feeling it after five minutes. And if you are doing 8 changes per hour, then you'd feel it in a bit less than 4 minutes.

So the general rule here is "6 room changes per hour". Some people recommend more than that, such as 8 room changes per hour or even ten per hour (once every six minutes). But for a typical studio, 6 per hour is a good starting point. And certainly no less than that (for example, 4 per hour would not be enough).

Therefore, you need to calculate the TOTAL air volume in ALL of your rooms, multiply that by 6, and that's how much air your AHU must be able to move, under normal circumstances, on average. That's NOT the maximum amount when it is running full bore! It's the normal amount when running normally. You also need some "headroom" in the system, for dealing with difficult days....

So when you dimension your HVAC system, your AHU must be able to move enough air to replace the entire volume in all of your rooms, 6 times per hour. This is just air that you are re-circulating through the room, to keep things nicely mixed, and comfortable.

That is your flow rate.

IN ADDITION to that, you need to have your "make-up" air ducts, that bring in the much smaller volume of fresh air, mix it with the recirculating air, and also take some of the recirculating air and dump it overboard. That might or might not need an additional fan to drive the make-up air, and you might or might not decide to add an HRV or ERV for the make-up air system, to recover some of the energy that would otherwise be lost from dumping the stale air (see here: Why your studio needs proper HVAC. )

Finally, in addition to all of the above, the AHU must have sufficient cooling capacity to FIRSTLY dehumidify the air passing through it, THEN ALSO cool it sufficiently. The dehumidifying thing comes first, whether you like it or not, since it is part of the process of cooling air, so you must take that into account. Whatever cooling capacity is left over AFTER the air has been dehumidified, is what actually reduces the temperature of the air. If you don't have enough capacity left over, then you will get warm air coming out of your AHU. Dehumidified, yes, but still warm, because the cooling capacity went into dealing with the "latent heat" of the humidity, and there wasn't enough to also deal with the "sensible heat" of the air itself. Your AHU must have the capacity to deal with both...

HVAC is a bit more complex than it seems at first glance!

Im fine with spending the cash and figuring it out, I want people to breath after all... but if my general occupancy will be less than 5 people at any one time, is that 6 changes per hour still the strong recommendation?

As I mentioned above, the circulation flow isn't really related to the number of people in the room: it is related to just moving air through the room, so that it mixes well and moves fast enough to keep things comfortable. This is just "moving air". It doesn't matte rif there is only one person in there, or ten. You still need the same re-circulation rate. That's the second aspect of HVAC. The part that DOES depend on the number of people, is the "CO2/ O2 / smelly odors" thing: That is a much lower rate that the re-circulation rate, and only applies to the OTHER part of HVAC, which is removing stale air and bringing in fresh air. These can actually be two separate systems, if you want: Have one smallish system to just bring in fresh air / remove stale air, then a larger system to move all the air through the room. That is possible. It's a good idea to join them together, though, to improve mixing and not waste energy. The best idea is a fully ducted system (mini-split) that combines both. It has an AHU that moves air through the rooms at the desired rate while also cooling that air and dehumidifying it, and it also has a point where the stale air is "bled off" to get dumped, and another where the fresh air comes in and gets mixed with the recirculating air, usually just before the AHU.

This article might help to clarify some of the details: Studio HVAC: All about mini-split systems, HRV's and ERV's

And does the ERV need to provided that or the ERV plus the minisplit? Most residential ERV's max out at 150CFM so they cant do this by themselves. Id have to buy a commercial one to even hit 300CFM. Help?

See above!

But in simple terms, your ERV (or HRV) only deals with the "make-up" air. It dumps the stale air and pumps in the fresh air. That's all it needs to do. It does not do the recirculating: that job is done by the AHU, which is usually a mini-split (ducted or ductless).

Whew! End of "Part B"!

OK, so that is my first post. I hope I provided everything needed to get some meaningful feedback. My post has received little traction on johnlsayers forum, so maybe if I "follow the Stuart" I might get some love here.

- Stuart -

Stuart, thank you so much for the very thoughtful responses. A few replies and additional questions.

Soundman2020 wrote:That must have been a major heartbreak! Real bummer, of the first order. I'm real sorry to hear that.

Many were much worse off than I was. I'm thankful to still have my house! I appreciate the sentiment.

Soundman2020 wrote:Source of the post Cool! So you are somewhat of a "sucker for punishment", as the saying goes! Ready to go another round with a heavyweight: "Studio Construction": But at least this time you know what you are in for,m and are much better prepared.

Yep!

Soundman2020 wrote:Source of the post Careful with "STC"! Don't confuse that with real isolation, more technically referred to as "Transmission Loss". Here's an article I wrote about that, a while back, that explains the issue. Why STC is not a good way of measuring studio isolation.

You probably meant "60 dB isolation", and that's a reasonable goal. Not easy to get there, but possible. It's towards the high end of what you can expect to get, realistically, for a home studio. To put that in perspective, a typical house wall will get you maybe 25-to 30 dB of isolation. A tight-budget home studio should be able to get around 40 dB, with some care to detail. 50 dB is typically what a home studio or project studio will get, if there is a decent budget, and that is usually enough for average needs. 60 dB implies 1000 times better isolation (in terms of sound power) than the original "typical house wall", and subjectively levels outside will be about 1/8th of that. The relationship is simple: each time you change by 10 dB, that's a ten-times change in power level, and a two-times change in subjective listening sound level. Thus, going from 30 dB to 40 dB sounds about half as loud, going from 40 dB to 50 dB is about half as loud again (so 1/4 as loud as the original), and 60 dB is yet another "half as loud" factor, thus 1/8 as loud as the original house wall. That is pretty darn good, in reality, and will certainly silence the problem with your lawn-mowing neighbor. Combined with the 300 foot distance to his house, that should also get your drummer down to very quiet levels, probably inaudible, at his place. So it's a reasonable goal, and achievable with a good budget and very careful attention to detail in the design and the build.

Yes, you are right and I did in fact confuse the two. I am aiming for 50-60 db of isolation. I have to be cost conscious, but I want strive for as close as I can get.

Soundman2020 wrote:Source of the post Tiny, square, and low ceiling! I'm not surprised at all that it sucked. Your new one can have about twice the floor area (maybe more), twice the ceiling height, and won't be square, so it certainly can be much better.

Yeah, you told me this at the time I built it too. I naively convinced myself I could "treat it into shape". Boy was I wrong! .... young and stupid.

Soundman2020 wrote:Source of the post While only two rooms will specifically be "studio" rooms, don't rule out the others! Bathroom, lobby, and even store room can all serve double-duty, for things that don't need isolation or mics. Eg, bass guitar player, keyboard player, electric guitar player.... they can all be sent out to those other rooms, with headphones, if space gets low in the main LR. Things like vocals and acoustic guitar can also be mic'd successfully in the CR, if necessary. It seems like Glenn already alerted you to this, but it is worth repeating here. Just remember to put patch bays in each of those other rooms, for emergency use. That includes patching for CCTV cameras and monitors as well (both directions). Musicians tend to play a lot "tighter" if they can all see each other, and also see the engineer. Ideally you want windows for that, but at a pinch you can do it reasonably well with CCTV.

Yes, you and Glenn have both convinced me to make sure no space goes unused. Every room can serve more than one function. It will require a bit more wiring, but likely worth it.

Soundman2020 wrote:Source of the post I can think of LOTS of places in your rough outline where you can have storage, that you probably haven't seen yet!

Do tell!

Soundman2020 wrote:Source of the post Not a problem! Studios can, indeed, have windows and natural light. When I'm designing places for clients, that¿s one of the big goals I try to aim for: an "airy" look, with as much glass as possible between rooms, and at least one room with windows to the outside. As you mentioned, I'd suggest that they should be non.operable (not opening), as that complicates the issue of isolation. It is a lot easier to get high levels of isolation with glass that is sealed in place! Here's one way to do that: site built windows for high isolation

Yes! This is very important to me. Glad it's a reasonable goal and achievable.

Soundman2020 wrote:Source of the post Hmmm... It sounds a little on the low side, for a high-isolation four-room studio. Assuming 75k for 500 ft, that works out to about $ 150 per square foot. That might be do-able if the majority of the labor is free, and you choose your materials carefully. It's probably OK, but if you can squeeze out a few more dollars, that would definitely be a good idea.

I fully expect to go over budget, it just might mean having to go a little slower and building it out over a longer period of time. I want it to be right, it's likely the last one I'll build. It's also possible to get it functional before I get it perfect. So as long as I can get the bones right, can alway improve over time.

I will do all of the work with friends with the exception of the pouring the slab. That will need to be contracted out. Otherwise, Im hoping its just materials and good will from friends.

Soundman2020 wrote:Source of the post In my opinion, RFZ with proper flush-mounted speakers ("soffit mounted"), is the best single things that anyone can do for any room. Flush mounting removes or greatly reduces most of the artifacts that arise from having a speaker inside the room, and RFZ creates the best possible acosutic response around the engineer. So RFZ should be your #1 priority. Room ratios are interesting, but nowhere near as big a thing as some people think. Here's an article I wrote about ratios and things a while back. It's rather long, but lays out pretty much all of the things you should be aware of: Modes, Room Ratios, and Schroeder

Also, if your room is not a perfect rectangle (and the room outline you show is not: it has six walls, not four, and two of them are angled, as well as the ceiling...), then ratios are really, really hard to figure out. The usual on-line room ration calculators only work for rooms with four mutually perpendicular walls, and parallel ceiling/floor, all with perfect 90° angles in all corners. If you angle just one of the walls, then those calculators no longer give accurate results. There are methods you can use to help estimate response of non-rectangular rooms, but accuracy is out the window. So there's no need to worry too much about ratios, as long as things are not square.

Great article to read on the topic! Definitely helped me to better understand what I am working with. It really highlights why bigger is better, but only to a reasonable degree. The take away is get close, but don't over think it. Treat the problem frequencies and move on with life.

Im 100% sold on RFZ design (though I will need help figuring out the details). My ultimate goal is to listen to something in my studio, take it to my car and have it sound the SAME. My old room clearly had some mode problems because everything sounded muddy when you took it to your car.

Soundman2020 wrote:Source of the post It's a good, one yes... but is not applicable to your room, since it is not rectangular. Also, see the article I linked to in "Part A" on modes.

OK so based on everything you helped explain on modes and RFZ designs, I should start with the rectangles, and apply an RFZ design within them.

check. This seems true for the control room but what about the live room?

Soundman2020 wrote:Source of the post Mmmm... If I had to guess, I'd say about 50% of the entire acosutic response of your room! Maybe more. Soffits are the biggest single thing you can do to improve your room. Any room. That's my opinion, of course: Other designers might not share that, but if you look at the final acoustic response graphs of what can be achieved in rooms with RFZ type design, it is impressive.

Sold, seems a crucial part of the RFZ design process. I want as close to an accurate mix room as I can get.

Soundman2020 wrote:Source of the post There are ways for dealing with windows at the rear of the room, but I'm wondering if a different layout of the rooms might be a better option. I think it might be possible to do everything you want to do, with a different layout of the rooms. I'm not certain, as I haven't tried anything on paper, but just from looking at it, I think there might be a better way to lay it all out (while still keeping your bathroom in that corner, of course).

Entrance, I really only have one reasonable spot to put a door in this design.
Why? I guess you are talking about the main door into the entire building? What is the restriction on locating that door? How far can it move, reasonably? For example, could it go a few feet to the left or right, or must it be exactly where you show it?

f. The window to the live room, I plan to make modular diffusers/absorbers that I can strategically hang when mixing, any reason that even if this was a first reflection point I couldnt just cover it up with one of those when I go to mix mode? (I understand I still need to ray trace
If your design forces you to have to cover up something in normal operation of the studio, then I'd suggest changing the design so that isn't necessary! Design the entire studio layout such that there are no objectionable reflections at the mix position within the first 20ms. In fact, that is part of the RFZ concept: No reflections above -20db in the first 20ms after the direct sound. (At very worst case, -10db within 10ms) It should not be necessary to "kludge" things in a studio that size, to meet the criteria on some occasions. It should be designed-in to the basic room layout. With a very small room, that might be the only way, but you have enough space to be able to achieve that, I think.

OK, so sounds like I need to revisit layout, and you are right, why make any compromises if I can solve them when building from the ground up. There is literally empty space there now, why make problems for myself??

As for the door, I just meant it was the only place to put it with my existing layout. If I want the entrance on the other side of the building I can certainly do that, again it's an empty plot of land now. The only immovable item is that the bathroom needs to be on that corner, but even that can be moved around by about 10' or so in any direction. Just has to remain in the "quarter" of the building.

Soundman2020 wrote:Source of the post g. Ceiling. Should I do a vaulted ceiling and follow the roof, or does it need to be a flat 9' height? More volume is better, but Im not sure if there is something I need to consider when detailing the rise and run of the ceiling.
For the Live Room: Definitely! Try to maximize height and volume: instruments (and musicians) do like height, to get the most "spacious", "airy" sound that they can. For the CR, the key issue is symmetry: If you can figure out a way to have the ceiling both vaulted and also symmetrical, then go for it!

a. Feels smaller than I'd like, but coming out of 10x10x7, especially now with 12' vaulted ceiling, I am hitting 1500 cubic feet of space and 156sqft of floor space. Is this workable for a live room? Will I hate life in there with a drummer and bass player?
I think it could be bigger. I think there are ways to lay out your building to maybe gain a few extra square feet in there, while at the same time improving the CR situation. Like I say, I haven't tried anything on paper: it's just a hunch. I think there might be a better way to organize things, and still hit all your key points.

b. do i need to splay the walls here? I know that any angle will help with reflection, but feels like I should prioritize square footage over angles.
In your case, I would go for the greatest room size. You need as much floor area (and volume) as possible, so do whatever ti takes to optimize that.

I'd be interested to see how you would lay it out. I did about 4-5 different versions and all of them felt flawed in some way. Maybe I can employ your services to give it a rough go. Nothing beats experience.

Soundman2020 wrote:Source of the post Houses are not studios! Houses are "leaky", in the sense that there are many other paths for air to get in and out, in addition to the HVAC path. Such as open doors and windows, cracks, gaps, holes, etc. Studios are sealed completely air-tight, twice over. Doors are always closed, windows don't even open.... It's a different situation.

Also, there's two very different concepts here that often get confused and muddle together. One is the total flow rate of the system: how much air you need to move through the room every hour, to ensure even mixing, good temperature distribution, proper humidity control, etc. The other is how much FRESH air you need to add to that, to keep people alive, and even more important, how much STALE air you need to remove in order to keep people alive.

Let's look at that second point, first: Many people assume that the reason for bringing in fresh air is to provide enough oxygen: that's partly true, but it's not the real reason. The REAL reason is that you need to get rid of the CO2! You exhale a large volume of CO2 with every breath, and it builds up fast in a sealed room. Since the concentration of CO2 in fresh air is very small (about 0.04%), you don't need to add a lot before the concentration gets up high. On the other hand, the concentration of oxygen is about 21%, so even if you use up a LOT of oxygen as you breath, there's still plenty there. You will die from CO2 poisoning long before you die from oxygen starvation, and CO2 rises very fast in sealed spaces, much faster than oxygen decreases. You pass out from CO2 poisoning long before you pass out from lack of oxygen. And way before that, at much lower CO2 concentrations, you start to feel bad, suffer headaches, nausea, vision problems, attention problems, ... way before your body even notices the slightly lower level of oxygen. You can die in a room that has plenty of oxygen available, if the CO2 level is high enough. You can live with only 15% oxygen in the room (6% points down from normal), but 6.04% CO2 (6% points up from normal) is not something you want to have in your room, if you plan to live.... .... That will kill you very, very fast.

(In addition to the CO2 thing, there's also the issue of other nasty stuff emitted by people, including various body odors.... You REALLY want to move air fast, to get rid of that)

So firstly, you need to REMOVE enough CO2 (stale air) to keep people alive, and in order to do that, you need to provide enough fresh air to replace the stale air that you removed. You dump a certain amount of the room air overboard, and you bring in the same amount of fresh air to replace it. This has NOTHING AT ALL to do with the re-circulation rate (we'll get to that below...) This is just about moving CO2 out and oxygen in.

In addition to keeping people alive and happy, you ALSO want to move a much larger volume of air around the room (re-circulation) and through the room: to ensure that the fresh air comes in then mixes with the room air fast, and gets to the people fast, so that the concentration of both CO2 and oxygen stays about the same THROUGHOUT the room. Consider this: If you sit still in one place and there is no air movement at all in the room, then you create a "bubble" of atmosphere around you that is high in CO2, low in oxygen, high in humidity, high in temperature, etc... while over in the corner of the room, it is cooler, dryer, and with a property balanced mix of CO2 and O2.

So, firstly you need to ensure that you are bringing in enough fresh air and removing enough stale air to keep everyone alive and comfortable. This is also sometimes called "make-up" air in HVAC terminology. And obviously, you need ducts in your HVAC system to do this. First, a duct that dumps some of the room air into the outside world, and ANOTHER duct that brings in the same amount of fresh air from the outside world.

That's the first part. That is based on occupancy: how many people there will be inside the room. It is not related to room size: just the number of living, breathing bodies in the room, that you want to keep living and breathing.

Then theirs the SECOND part, which is recirculating air through the room to ensure good mixing, so that temperature, humidity, CO2, and O2 are pretty much constant throughout the room, with no "pockets" of hot, humid, "bad" air, nor of cold, dry, "good" air. There's also the issue of "speed". Not in the sense of how fast the air comes out the HVAC registers, but rather in terms of how fast it gets to you.

Think of it this way: if you are (hypothetically) sitting in the middle of a room, and the HVAC register is in one of the walls, then it takes a certain amount if time before the air arrives at your location. So, let's say you arrive at your room in the late afternoon, after a real scorcher, and it is hot and humid inside the room. So you sit down at your console, turn on the HVAC, and wait. If the HVAC system is circulating air at the very low rate of one room change per hour, and you are in the middle of the room, then it will be HALF AN HOUR before you start to feel the effects. Half an hour, because the air is moving at 1 change per hour, and you are in the middle. If you were up against the far wall, opposite the HVAC register, it would take an entire hour before you start feeling the effects!

On the other hand, if you are circulating air at the rate of 6 changes per hour, that is one change every ten minutes so you start feeling it after five minutes. And if you are doing 8 changes per hour, then you'd feel it in a bit less than 4 minutes.

So the general rule here is "6 room changes per hour". Some people recommend more than that, such as 8 room changes per hour or even ten per hour (once every six minutes). But for a typical studio, 6 per hour is a good starting point. And certainly no less than that (for example, 4 per hour would not be enough).

Therefore, you need to calculate the TOTAL air volume in ALL of your rooms, multiply that by 6, and that's how much air your AHU must be able to move, under normal circumstances, on average. That's NOT the maximum amount when it is running full bore! It's the normal amount when running normally. You also need some "headroom" in the system, for dealing with difficult days....

So when you dimension your HVAC system, your AHU must be able to move enough air to replace the entire volume in all of your rooms, 6 times per hour. This is just air that you are re-circulating through the room, to keep things nicely mixed, and comfortable.

That is your flow rate.

IN ADDITION to that, you need to have your "make-up" air ducts, that bring in the much smaller volume of fresh air, mix it with the recirculating air, and also take some of the recirculating air and dump it overboard. That might or might not need an additional fan to drive the make-up air, and you might or might not decide to add an HRV or ERV for the make-up air system, to recover some of the energy that would otherwise be lost from dumping the stale air (see here: Why your studio needs proper HVAC. )

Finally, in addition to all of the above, the AHU must have sufficient cooling capacity to FIRSTLY dehumidify the air passing through it, THEN ALSO cool it sufficiently. The dehumidifying thing comes first, whether you like it or not, since it is part of the process of cooling air, so you must take that into account. Whatever cooling capacity is left over AFTER the air has been dehumidified, is what actually reduces the temperature of the air. If you don't have enough capacity left over, then you will get warm air coming out of your AHU. Dehumidified, yes, but still warm, because the cooling capacity went into dealing with the "latent heat" of the humidity, and there wasn't enough to also deal with the "sensible heat" of the air itself. Your AHU must have the capacity to deal with both...

HVAC is a bit more complex than it seems at first glance!

Ok this post should stay sticky just for this answer alone. I get it now. I had NOT thought about the time it takes to "condition" the room, I had only thought unilaterally about replacing air as it related to "oxygen". From experience with my last poorly designed system, this is really crucial. ANYONE READING TAKE NOTE: if you think you can get away with tapping your home AC and just piping it in, you are wrong. VERY VERY wrong. Dont do this. Design is it right.

This is actually why I honestly started with even picking HVAC equipment that sort of got me to the 6 changes an hour threshold, but I didnt really understand why. I was just following the math. So what I picked out should work, but I might even upsize it a bit. The ducted minisplit will have the ERV as a side chain on the supply to the room. Sounds like I'm on the right track, but needs tuning.

This is all really great information.

I just edited your post to highlight the really, really important point you made about HVAC. Hope you don't mind! That's a great comment, and so very true. Coming from you, as someone who "went there and did that", it carries more weight than if I just said it as a suggestion. Maybe I went a little overboard with the highlight (!), but that's very important.

- Stuart -

eightamrock wrote:Source of the post OK so based on everything you helped explain on modes and RFZ designs, I should start with the rectangles, and apply an RFZ design within them. check. This seems true for the control room but what about the live room?

The live room is far less critical. Control rooms are supposed to be very neutral, clean, transparent, having no sound of their own, which is why they need so much treatment, so much attention to detail. But live rooms are supposed to have some "character", some attractive sound of their own that musicians like, and that keeps them wanting to come back to your place. A live room that is treated to sound neutral like a control room, would not be interesting for most musicians. They would consider it lifeless, dull, etc. So a live room needs to be,... well... "live"! It can have some coloration, and a pleasant "tone" of its own. So you don't need to be concerned about shape, symmetry, neutrality and transparency, as you would be for a CR. The room can be non-rectangular, and have angled walls, vaulted ceilings, etc. In fact, if you do it right, you can have "zones" within the room, with slightly differing acoustic response, so musicians can move around a find a spot that they like, and where you can move mics around to find a spot that the mic "likes". So you could have one part being "drier" while another part is "brighter", etc. That's harder to do in a small room: large rooms are better for that. But it's worth making an attempt. Another option is to give the live room "variable" acoustic treatment, to give you more flexibility. That's all about treatment devices where you can slide, flip, open, close, rotate etc. some parts, to change the acosutic response. Here's something about that: What is variable acoustics? How do I do that?

So, you can make your live room any shape that you want, then apply treatment to get it to sound the way that you want it to sound. But do also ask your musician friends what they consider "attractive" and "inviting" in a room where they like to play, and take that into account. Musicians know what they like, and what sounds good. Ditto with any producer friends you might have. Get lots of input from people who know what good rooms sound like, and try to qualify that in acoustic terms, such as frequency, phase, time, resonance, reverberance, etc. Then try to design the room to achieve that as much as possible. You do want your place to be somewhere that musicians WANT to come, to track, jam, rehearse, etc! And where producers want to come, to do their projects...

- Stuart -

Soundman2020 wrote:Source of the post I just edited your post to highlight the really, really important point you made about HVAC. Hope you don't mind! That's a great comment, and so very true. Coming from you, as someone who "went there and did that", it carries more weight than if I just said it as a suggestion. Maybe I went a little overboard with the highlight (!), but that's very important.

- Stuart -

I dont mind at all! I hope that it saves someone from making a very grave mistake like I did.

Well, I am back to the drawing board on layout now that I have a bit more information. Can we talk about corner control rooms? As it relates to modes (specifically bad modes), how do people get away with "squarish" corner control rooms?

Here is an example which I am sure will look familiar. Without the dimensions, I think your clients build is fairly close to my own aspirations.

This control room looks way more square than I would expect. I realize he is oriented on the diagonal, but how does this work given the issue with square rooms? Given he built from scratch Im quite surprised that he made this compromise to forgo a much larger room. Any insights into why you guys did it this way?

eightamrock wrote:Source of the post Any insights into why you guys did it this way?

To maximize the live room size, basically. This was a sort of "one-person studio" situation, where there wasn't much need to have a lot of people in the control room, but the live room needed as much space as possible, so that's the way I designed it.

As it relates to modes (specifically bad modes), how do people get away with "squarish" corner control rooms?

Ah, now there's the 64 thousand dollar question, isn't it?

As you figured out, a corner control room must have equal dimensions in order to have symmetry, which makes it "square" from one point of view. But as you can see here, in reality it is more of a "truncated trapezoid": One of the corners of the square is cut off, and the shape is either squashed or stretched a little, so it isn't truly "square". But the underlying problem remains: the modes in the two directions line up, and are problematic.

There are ways of dealing with that, but it isn't easy. Firstly, if you take a close look at that diagram, you can see that the rear corner is full of acoustic "stuff", that is doing lots of things at once. There are some giant slat resonators and Helmholtz resonators buried in there:

Those are built using 2x4's, carefully shaped, gapped, and located to treat the exact resonant frequencies.

Those are kind of complex, and have several different things going on at once, with different types of insulation carefully located inside. I can't go into all the details, but here's a rough "behind the scenes" view.

There's also hangers, diffusers and other stuff going on in that corner. It does a lot!

The disadvantage of corner control rooms is that the modes line up. The advantage, is that the modes line up! Which means you only need to tune things to treat one well-defined set of modes. But it also means they need to be BIG, properly tuned, and properly built.

Do they work? You be the judge . Here's a set of "before" and "after" acoustic tests that were done just before the rear wall treatment wend in, and just after.

Waterfalls:

BEFORE:

AFTER:

Spectrogram:

BEFORE:

AFTER:

Decay times:

BEFORE:

AFTER:

So yeah, I'd say that they work!

That was the very first treatment that went in: There are many other things that happened along the way in treatment and tuning, then this is the final result:

FREQUENCY RESPONSE; FULL SPECTRUM:

WATERFALL, FULL SPECTRUM:

That's a small room, too: Floor area is about 13m2 (144 ft2).

So it can be done: A small corner control room can, indeed, produce respectable results, but do bare in mind that it was carefully designed from the ground up to achieve exactly this.

In your case, you would probably want to go a bit bigger on the CR, and I'm not entirely convinced that this is the best option for your situation, but it certainly is an option!

- Stuart -

Sorry to drag you all back a few posts, to post 7, but I wanted to addd something.

Soundman2020 wrote:Source of the post Many people assume that the reason for bringing in fresh air is to provide enough oxygen: that's partly true, but it's not the real reason. The REAL reason is that you need to get rid of the CO2! You exhale a large volume of CO2 with every breath, and it builds up fast in a sealed room. Since the concentration of CO2 in fresh air is very small (about 0.04%), you don't need to add a lot before the concentration gets up high. On the other hand, the concentration of oxygen is about 21%, so even if you use up a LOT of oxygen as you breath, there's still plenty there. You will die from CO2 poisoning long before you die from oxygen starvation, and CO2 rises very fast in sealed spaces, much faster than oxygen decreases. You pass out from CO2 poisoning long before you pass out from lack of oxygen. And way before that, at much lower CO2 concentrations, you start to feel bad, suffer headaches, nausea, vision problems, attention problems, ... way before your body even notices the slightly lower level of oxygen. You can die in a room that has plenty of oxygen available, if the CO2 level is high enough. You can live with only 15% oxygen in the room (6% points down from normal), but 6.04% CO2 (6% points up from normal) is not something you want to have in your room, if you plan to live.... :shock: .... That will kill you very, very fast.

CO2 levels are shown at, for example, www.kane.co.uk. UK outdoor air is usually around 400ppm. 5,000ppm is a common maximum indoor workplace level maximum.

My experience is that I am used to around 300ppm, probably because I live near mountains where the air is known to be good and I am an outdoor type, one who at home usually has at least one window open. At 600ppm (frequently at home with all the windows closed) I can tell the difference and would normally open a window. At 900ppm (sleeping alone with the window closed) I wake up feeling it is a bit muggy. At 1,200ppm overnight (two of us in the same room with the window closed) I wake up feeling groggy with a mild headache whereas my wife is fine and it doesn't bother her at all. Our CO2 meter's display goes from green to yellow at 1,000ppm and to alarm red at 1,400ppm.

Based on my experience having now bought a CO2 monitor for the studio - and tested it at home - I would not like to experience the 5,000ppm indoor workplace maximum; I would be gasping for air. Perhaps we are all different.

or this: https://www.onsetcomp.com/files/blog-im ... 0chart.png

Soundman2020 wrote:Source of the post
eightamrock wrote:Source of the post Any insights into why you guys did it this way?
To maximize the live room size, basically. This was a sort of "one-person studio" situation, where there wasn't much need to have a lot of people in the control room, but the live room needed as much space as possible, so that's the way I designed it.

As it relates to modes (specifically bad modes), how do people get away with "squarish" corner control rooms?

Ah, now there's the 64 thousand dollar question, isn't it?

As you figured out, a corner control room must have equal dimensions in order to have symmetry, which makes it "square" from one point of view. But as you can see here, in reality it is more of a "truncated trapezoid": One of the corners of the square is cut off, and the shape is either squashed or stretched a little, so it isn't truly "square". But the underlying problem remains: the modes in the two directions line up, and are problematic.

There are ways of dealing with that, but it isn't easy. Firstly, if you take a close look at that diagram, you can see that the rear corner is full of acoustic "stuff", that is doing lots of things at once. There are some giant slat resonators and Helmholtz resonators buried in there: FRCAUS--20180125_151839-Rear-bass-trap-ENH.jpg FRCAUS--S2870022.jpgThose are built using 2x4's, carefully shaped, gapped, and located to treat the exact resonant frequencies.

Those are kind of complex, and have several different things going on at once, with different types of insulation carefully located inside. I can't go into all the details, but here's a rough "behind the scenes" view. FRCAUS---V11-S181-CL--SKP-2017--S314-slotted-poly-interior.jpgThere's also hangers, diffusers and other stuff going on in that corner. It does a lot!

The disadvantage of corner control rooms is that the modes line up. The advantage, is that the modes line up! Which means you only need to tune things to treat one well-defined set of modes. But it also means they need to be BIG, properly tuned, and properly built.

Do they work? You be the judge . Here's a set of "before" and "after" acoustic tests that were done just before the rear wall treatment wend in, and just after.

Waterfalls:

BEFORE:
FRCAUS--REW-WF-20-500--131hz-highlighted--BEFORE.png

AFTER:
FRCAUS--REW-WF-20-500--131hz-highlighted--AFTER.png

Spectrogram:

BEFORE:
FRCAUS--REW-SP-20-500--131hz-highlighted--BEFORE.png

AFTER:
FRCAUS--REW-SP-20-500--131hz-highlighted--AFTER.png

Decay times:

BEFORE:
FRCAUS--REW-RT-20-20k-BEFORE.png

AFTER:
FRCAUS--REW-RT-20-20k-AFTER.png

So yeah, I'd say that they work!

That was the very first treatment that went in: There are many other things that happened along the way in treatment and tuning, then this is the final result:

FREQUENCY RESPONSE; FULL SPECTRUM:
FrKCAUS-REW-FR-12-22k--1..3-FINAL.png

WATERFALL, FULL SPECTRUM:
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That's a small room, too: Floor area is about 13m2 (144 ft2).

So it can be done: A small corner control room can, indeed, produce respectable results, but do bare in mind that it was carefully designed from the ground up to achieve exactly this.

In your case, you would probably want to go a bit bigger on the CR, and I'm not entirely convinced that this is the best option for your situation, but it certainly is an option!

- Stuart -

Well I appreciate the explanation! Corner control rooms really seem like a last resort, or a very deliberate result of some other requirement. Luckily I don't have that!

I spent that better part of the day trying to figure out why I couldn't fit (2) 200ft2 rooms in my building with a bathroom and closet, well it turns out I dont actually have 500 full square feet. The pad I put down is 18' x 28' which is 504ft2. however once you account for the 2x6 outer wall, the 1" air gap, and the 2x4 inner wall, I lose 100ft2 of space. So really, I only have about 400ft2 to work with.

With that said, I really do like the layout I picked above. It favors the CR at roughly 200ft2, the live room with a little over 150ft2 and the storage, bathroom, and airlock taking up the last of the space.

I plan to work the control room into an RFZ design, the only concern I have is that where I have the entrance to the CR, it might get in the way of building bass traps. I have enough space for a 12" deep corner trap on the side with the door. Will that be workable?

There are few reasons I like this layout, but tell me if Im crazy:

Im starting to get into analysis paralysis. These rooms are much bigger and more thought through than my last studio.

Thoughts?

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