Nashville Studio Build (need design help first!!!)

[Shybird]

Here is a shot of the control room...

[Shybird]

And here's the ISO...

A little cramped for drums...but still workable...what do you guys think?

Also, regarding the sliding doors, I know they are supposed to be slightly angled from one another but didn't know if I should actually angle the walls or just the doors in the space between the walls...I feel like I've seen it done both ways so I'm confused as to which route I should take.

Thanks!!
Trevor

[Shybird]

In case anyone wants to mess around with the sketchup file, here it is:

https://www.dropbox.com/s/y05tp4iifqh7j ... loorplan-2

I forgot to make layers as I went so it's all on one layer...still learning lol.

Let me know what you think of the plans!

Cheers
Trevor

[RJHollins]

Hi Trevor.

I've been following your thread as it develops ...

Something you've probably considered ... and yes, design, layout, traffic flow, is an
Art & Science !!! I did want to comment on the 'drum booth' though.

The first issue ... getting drums into the booth ... seems the only way is through the control room ! As I drummer [too], I can say that [many time] whenever a drummer shows up, AND he brings his equipment ... it can be both a time of celebration, along with turning the room into a disaster [for lack of a better term]. For many, the number of trips back and forth, the pile of stands dropped on the floor, empty cases, bags, you name it ... will cause a major disruption in the control room.

[Shybird]

Hey RJ thanks for tuning in...I need all the support and help I can get!

Those dotted lines on the front of the booth are going to be double sliding doors! Sorry if that was not clear in the drawing. That should take care of the issue you are speaking of right?

[Shybird]

a time of celebration

haha... I understand this concept a little too well...always had to tell our drummer to get there at 7 if we wanted to see him by 9 at best! lol

[Shybird]

Hey guys, hope everyone had a great 4th!! Or for those not in the states, a great random Wednesday lol...whichever way you may have celebrated.

Anyways, I'd love to hear what you all think about the most recent design...I have been doing lots of research regarding other parts of my build, and I want to start running with some things but before I do I really wanted to get some constructive feedback.

Some things I've been looking into...

-I really want to shoot for an RFZ design in the control room so I've been looking into that and what it will take (got the Master Handbook of Acoustics in the mail a few days ago...whew what a read so far haha). However I can't find much regarding corner control room layouts and RFZ designs. I know it can be done since the principles are really the same... I just have learn how to apply it to my situation. Anybody got some links or good reads on this?

-I also have been doing research on how I want to build my outer shell. I've come to the conclusion that something along the lines of "scissor" trusses would be ideal since it would allow me to get some extra height in the live room. I was hoping to meet with my builder today but it looks like he is busy until I get back from my trip to Lexington. My cousin's wedding is on Saturday and I'm the best man...should be a fun time .

Well that's it really...just wanted to give a quick update!
Trevor

[Shybird]

Alright, so I've been doing a ton of ray-tracing and it looks like it will be impossible to achieve a true RFZ given the small dimensions of the control room...the back two walls are too close to the mix position and there is no way to provide the necessary angles for deflection. The only answer it seems would be to pad that wall with a good amount of absorption in hopes that the reflections would at least be diminished in their overall dB level. However, there is no way to keep them from arriving within 20ms from the direct signal so it would not be a true RFZ (I hope I've got this concept right and didn't just sound like a fool ). I realize that shooting for 15ms and sometimes even 10ms is the best one can do but I really want to do this right since we are pretty much starting from scratch.

Now for the more exciting part of the update... we've decided to talk to the builder about extending the concrete slab just a little further in a couple of directions (since we will already be tearing up concrete and pouring anyways)...I've attached a picture to demonstrate what we would be doing. The "unchanged concrete" is the part of the slab that is already level and well made; the "new concrete" is part of the slab that we were going to cut up and redo in order to square off the corners, tie it in better with the "unchanged concrete," and make it level; the "additional concrete" is the update I am speaking of here...it would allow for a few great enhancements to the studio:

-more floor space in every room
-larger air gaps in the walls between rooms for more isolation (using 2x6 studs as shown in the drawing with 24" oc)
-a true RFZ design in the control room

A couple things/questions to consider:

-Given that the builder agrees this is possible (structurally speaking) we can add up to 4' of "additional concrete" before we'd be violating codes (the distance from the outer wall to the property line has to remain 5')...however I only went 3.5' because it keeps the live room 50% bigger than the control room (if I go 4', the live room is only 44% bigger)...Stuart I guess this is a question for you because I had read a post you made regarding this issue. You said something along the lines of, "the live room should be at least 50% larger than the control room otherwise the engineer would not be able to hear the reverb tails of the live room considering that the control room's reverb tails would 'mask' those of the live room"...this makes since to me however does this "volume/reverb" issue apply to the outer shell of the control room or the inner shell that is controlling the RFZ? I'm just trying to decide how much "additional concrete" would be necessary to create the most optimum dimensions for all the rooms...

-Notice I've only drawn the inner shell of the control room on the right side...these angles provide a "reflection free zone" based on lots of trial and error with ray-tracing. However, I cannot draw the same angles on the left side because I have the sliding doors...this is where my question lies: is there any way I could keep the sliding glass doors and provide proper angles for an RFZ or is this one of those "compromises" where it's either sliding doors or RFZ? I realize one answer is changing the layout all together but I really like the flow that has been achieved with this one...and honestly I'm not too worried about sliding doors if I can have a great RFZ control room design. Sorry if I'm talking in circles...

-What type of inner shell materials would provide reflections for a large enough range of frequencies? I've read many different opinions about RFZ and what range of frequencies need to be controlled...one opinion was that if you can achieve an RFZ down to 1k, then that would pretty much take care of any stereo imaging problems etc...what are your opinions on this issue?

-Then depending on how low I would need to go ( ) (still talking about frequencies here lol) to achieve the best possible RFZ, would there be a limit regarding mass just because of a potential 3-leaf effect with the outer shell? I'm just a little confused on what materials would be used for this inner shell and how they would not create the dreadful 3-leaf effect ...also I'm assuming that whatever frequencies are allowed to pass through the mass, would then enter the cavity which could be designed to act as a trap (between the inner RFZ shell and inner drywall)?? am i crazy?

-Oh... and I guess it goes without saying but we are sort of pushing the budget to the side for a while until we achieve exactly what we want out of the design...then we will scale down as need...but there's quite a bit of wiggle room in the budget if it means the difference between an average studio and a phenomenal studio. All in all we want the money to be well spent!

Well I guess that's enough insanity for now...hope it was readable.

And thank you in advance for any replies...I cannot express enough how much I appreciate the incredible services provided by this forum!

Cheers
Trevor

[Shybird]

Also... the ray tracing is only a rough beginning of the potential RFZ... I realize there are several areas I have not adressed yet (not to mention the ceiling). I just wanted to get a better understanding of the materials and whatnot before I continued drawing like a madman...

Thanks
Trevor

[Shybird]

Here is an example of the control room without the sliding doors...

I was continuing my ray-tracing extravaganza and began to realize I have no idea how to tackle this in a way in which the reflections from the right speaker do not bounce back to the listening position off of the left walls (and vice-verse)...I got it to where the reflections from the right speaker off the right walls are good though! (that's not saying much I know...) So how do I go about designing such a wide space like this so that a true (or at least as good as possible) RFZ is achieved? Does anybody know of similar corner layouts that were able to achieve a good RFZ? I guess I might have to begin experimenting with monitor angles, placement, etc...

A couple other things:

-I've not been able to find specs that show the dispersion characteristics of my Event ASP8's...anyone know where to find such a thing?

-Is there a way to design the soffits so that they can house larger monitors in the future but only my Event's for now? (I think I read where this has been done and also is recommended if an upgrade is foreseeable)

Thanks guys
Trevor

[Soundman2020]

it looks like it will be impossible to achieve a true RFZ given the small dimensions of the control room...the back two walls are too close to the mix position and there is no way to provide the necessary angles for deflection.

To me, it looks like you have your mix position and intersect point too far back in the room. I think I would try to bring the mix position further forwards, and toe-in the speakers a bit more. That should help with your angles and times.

However, there is no way to keep them from arriving within 20ms from the direct signal so it would not be a true RFZ (I hope I've got this concept right and didn't just sound like a fool ). I realize that shooting for 15ms and sometimes even 10ms is the best one can do but I really want to do this right since we are pretty much starting from scratch.

What times are you seeing in your calculations? It's hard to get 20 ms unless you have a fairly large room. In other words, how long are your rays (from speaker to ear) for the earliest bounces off the rear wall?

Also, it isn't just time; it is level as well. You need to get the level down by 20 dB. And getting both 20 ms and 20 db is really hard. 15/15 is easier, and probably do-able in your room.

But looking at your ray-trace diagram, it seems that you are reflecting the rays at the front face of what I assume is a large superchunk on the side/rear wall: Why did you do that? Are you planning to wrap your bass traps with something reflective, like thin plastic, in order to keep highs in the room? Or is that a mistake?

You said something along the lines of, "the live room should be at least 50% larger than the control room otherwise the engineer would not be able to hear the reverb tails of the live room considering that the control room's reverb tails would 'mask' those of the live room"...this makes since to me however does this "volume/reverb" issue apply to the outer shell of the control room or the inner shell that is controlling the RFZ?

Pretty much everything is referenced to the inner-leaf surfaces: what you see when standing in the finished room, before any acoustic treatment is installed.

And as with most "rules" in acoustics, then 50% figure is just a guideline: so don't go jump off a cliff if you can only get 40%, or whatever!! It is what it is. As long as there is a reasonable difference in size, you'll be fine.

However, I cannot draw the same angles on the left side because I have the sliding doors...this is where my question lies: is there any way I could keep the sliding glass doors and provide proper angles for an RFZ or is this one of those "compromises" where it's either sliding doors or RFZ?

I'm not sure I understand: the left and right side walls seem to be symmetrical to me. So what works for the right wall must also work for the left wall, regardless of whether we are talking about glass or drywall: there isn't much difference in reflectivity.

Also, you might be taking your ray-tracing to unnecessarily high angles. It is mainly mids and highs that you should be concerned about, not lows. Lows are not directional, and act more like expanding hemispheres, while highs are very directional and act more like rays. Your speaker manual should show you what the dispersion angles are for each frequency band, so take a look at those polar patterns to see what type of angles you should be worried about. There is practically no high-frequency energy going out at angles of 60° or 70° off-axis: Most of it is going out in a cone within about 30° or so of the axis. So you might want to ray-trace out to, say 55°, just to be sure, but there's no need to go out to 80°, for example.

-What type of inner shell materials would provide reflections for a large enough range of frequencies? I've read many different opinions about RFZ and what range of frequencies need to be controlled...one opinion was that if you can achieve an RFZ down to 1k, then that would pretty much take care of any stereo imaging problems etc...what are your opinions on this issue?

1 kHz sounds about right, which is kind of what I was talking about above. You only need to worry about the top half of the spectrum (1k to 20k). The bottom half is not so important, and the lower you go, the less directional it is anyway.

Your inner-leaf materials should not be frequency-based: the inner leaf is there for isolation, not treatment, so they should reflect all frequencies as well as possible. That's why you need heavy, massive, rigid materials, such as concrete, glass, drywall, brick, etc. Different parts of the spectrum are governed by different physical characteristics.

-Then depending on how low I would need to go (still talking about frequencies here lol) to achieve the best possible RFZ, would there be a limit regarding mass just because of a potential 3-leaf effect with the outer shell?

Not really: you seem to be confusing isolation and treatment. They are two different and opposite things. Isolation does one thing: it stops sound leaving the room. That's all it does. And obviously, if it is stopping sound form leaving the room, then it must be keeping the sound inside the room, where it bounces around all over the place, making the room sound bad. That's what treatment is for: to fix the problems created by the "bouncing around", which was in turn caused by the isolation. If you did not have any isolation at all, then you would also not need any treatment at all: Your studio would have to be in the middle of an empty field, with no walls or roof at all. With zero isolation, no sound ever comes back, so no treatment is needed. But since that is a bit impractical, you have to have a room around you, so that's where the problems start. Any type of room at all implies some amount of isolation, which in turn implies some level of "bouncing around", therefore needing some form of treatment. The better the isolation, the WORSE the room sounds, so more isolation is needed.

So try to think of your build as being two entirely different things: Isolation to keep the sound in which makes your room sound bad, and treatment to make it sound good again.

I'm just a little confused on what materials would be used for this inner shell and how they would not create the dreadful 3-leaf effect ...

I don't think I understand: There should be only 2 leaves: the outer one (the building wall itself, probably) and the inner one, which is what gives the room its shape. If you stand inside the room after you finish building it, but before you put any treatment at all in it, then what you see around you is the inner leaf. Everything you add after that is treatment, and that will be mostly absorption, perhaps some diffusion, and perhaps some form of resonant device. So building your inner leaf should not ever create a three-leaf system, unless you built the outer leaf wrong, with two leaves.

About the only except I can think of is a panel trap (membrane trap), which could theoretically create a 3-leaf system, but in that case it is only a small part of the total wall area that would be 3-leaf, and since that trap would most likely be tuned to a much higher frequency that the MSM resonance of the wall itself, it shouldn't be an issue.

also I'm assuming that whatever frequencies are allowed to pass through the mass, would then enter the cavity which could be designed to act as a trap (between the inner RFZ shell and inner drywall)?? am i crazy?

Now you are really confusing me! The only "cavity" is the one between the inner leaf and outer leaf! What cavity are you talking about? The "RFZ shell" is the inner-drywall! So how can there be an cavity between that drywall and itself, when it is the same thing?

You lost me there...

-Oh... and I guess it goes without saying but we are sort of pushing the budget to the side for a while until we achieve exactly what we want out of the design...then we will scale down as need...but there's quite a bit of wiggle room in the budget if it means the difference between an average studio and a phenomenal studio. All in all we want the money to be well spent!

Ahhh! Yes, about budget. The correct way to estimate the budget for a studio build, is to come up with the largest possible amount of money that you could ever image spending on it, multiply that by a randomly chosen number between 2 and 10, add the cost of an outrageously expensive luxury car, then add a couple of zeros on the end...

- Stuart -

[Shybird]

Hey Stuart thanks for the detailed reply!!! Sorry I did not get back to you yesterday...I was not feeling well and couldn't keep food down all day...feeling a bit better this morning...not sure what got into my system

Anyways...I think I should clear up what I was thinking I could do to achieve the desired RFZ...I had read in a few posts that the inner shell of the control room (the drywall) could be thought of as the "isolation" and then smaller partitions (walls made of thinner wood/mdf I guess? and then filled with insulation behind?) could be built within that inner shell (the drywall) which would control the angles of reflections for the mids/highs as well as act as bass traps...however based on what you are saying it looks like my line of thinking was completely wrong.

The reason I thought that some people took this direction was that their rooms could not be built to accommodate the proper RFZ angles with the drywall (isolation wall) itself...therefore they talked about building "false walls" and "false ceilings"...however I must have confused what it was they were talking about. So are you saying that the reflections for the RFZ MUST be controlled by the drywall angles (or in other words, inherently WILL be controlled by the drywall)? And the only thing left beyond that is absorption, resonators, and possibly diffusion to treat the room? But there is no controlling reflections for RFZ beyond (within) the drywall? (I just thought there were different types of panels and whatnot that I could build within the drywall to help control reflections and complete the RFZ...at least in the few trouble spots that are created by my corner control room design...is this not accurate thinking?)

I'm currently working on ray-tracing this room again...WITHOUT those inner "false walls" that I thought could control the angles for the RFZ...

I will return with a new drawing giving times etc...I'm sorry about all the confusion I caused...things I read on here can sometimes be misleading for a newb like myself...anyways thanks again for the reply Stuart! I can't thank you enough.

sincerely
Trevor

[Soundman2020]

and then smaller partitions (walls made of thinner wood/mdf I guess? and then filled with insulation behind?) could be built within that inner shell

Well, you certainly can add panels inside the room to move reflections to different locations. Once example of that is a hard-backed cloud. Another is a gobo. But putting insulation behind won't affect how well it reflects. And if it is over a sealed cavity, then you have created a panel trap, which will resonate and absorb energy at a certain frequency, or range of frequencies. So it will reflect mids/highs, resonate at its tuned frequency, and perhaps absorb some lows, depending on the design. If you really want to go that route then you could, but it is going to take a lot of calculation to figure out your resonance, reflection range, and absorption range, in addition to just figuring out your reflection angles. And what frequency would you tune it to? If your room is non-rectangular, then you cannot easily predict the modes of the room. So you'll have to wait until the room is entirely finished so you can measure the modal response, then build your tuned/reflective/absorptive panel traps.

Another issue is the risk of creating a third leaf: Any time you place a large flat massive surface close to a 2-leaf wall, then you turn it into a 3-leaf wall, which can reduce isolation in the lower end. So you'd have to take that into account when you design your isolation system, to make sure that you have more mass on the middle leaf and a larger air gap, in order to compensate.

So you could do that, with sealed tuned reflective absorptive panel traps, but it will be a lot of work to figure out all those things.

Another option is to do what John does, using slot walls. They can be tuned to be broadband absorbers, while also being largely reflective and also somewhat diffusive.

therefore they talked about building "false walls" and "false ceilings"

Do you have any links to threads where people have done that successfully, where the face of the "false" wall is something substantial, such as drywall?

so are you saying that the reflections for the RFZ MUST be controlled by the drywall angles (or in other words, inherently WILL be controlled by the drywall)?

It's not that they "must" be controlled by the inner-leaf, but rather that this is usually the easiest way to do it. If you add a third leaf in front of that, either sealed or not sealed, then you have changed the room dimensions, modal behavior, and isolation, so you need to consider what effects you might be creating like that. For example, let's say you tune your panel trap to 1000 Hz. So now you have a surface that is reflective for most frequencies, except for 1000 Hz. So music reflecting from that surface will be deficient at 1000 Hz. You will have sucked out some energy from the music around that frequency, and the reflected sound will now be lacking that. Is that what you want? If the partition is thin, then it will also allow low frequencies through, which will then bounce off the "real" inner leaf behind, and come back out again at a different angle, and also delayed in time. So the low end will be smeared in time and space, and also reduced in level with respect to the rest of the spectrum. In other words, your music will have a notch cut out of it at 1 kHz, plus timing and phasing issues in the low end. That might not be what you want in a control room!

And the only thing left beyond that is absorption, resonators, and possibly diffusion to treat the room?

Those are three normal ways of treating a room, yes. There are some others, but not really applicable to home studios.

things I read on here can sometimes be misleading for a newb like myself.

And for the rest of us too! Acoustics is a little bit counter-intuitive in some aspects, and even simple things can turn out to be far more complex than you expected, once you get into it!

So, to summarize: yes you could use panels to help create your RFZ, but you'd have to do so with care to avoid messing up other aspects of the room. In fact, an offshoot of RFZ called "CID" (for "controlled image design") does just that: it sets up many large, angled panels at various key points around the front of the room, to better direct reflections away from you. So it can be done, but it isn't as easy as a "standard" RFZ design.


- Stuart -

[Shybird]

Ahh that clarifies so much!! Thanks Stuart...let me do some homework and hopefully my next post will be something much more substantial. I'd like to avoid making an RFZ design any more difficult than it needs to be! I'm definitely not ready to attempt something that even a professional is hesitant towards...

That being said...I guess my options now are to keep the room as is (or pretty much as is) and not go for a full-out RFZ (if I went that route, do you think this particular corner room could be made to sound good with proper treatment once it is built and the modal response is measured?)...or I could change the layout altogether so that I can achieve a more standard RFZ with proper drywall angles...I'm trying to decide how much I need to shoot for this whole RFZ thing...I've read so many testimonials where engineers love the results and say they can mix for longer periods of time without becoming fatigued by an overly "dead" room...I'd really like to achieve the more "natural" sounding control room that an RFZ can provide.

Ahh decisions decisions...

Cheers and thanks again!
Trevor

[Soundman2020]

Actually, the shape of a corner control room is inherently RFZ...

RFZ is much more about the angles in the front half of the room, particularly the side walls, and pentagon shape fits that very well.

Your issue isn't so much the angles at the front, as the absorption at the rear. The basic concept is that the front of the room sends first reflections around the engineer, towards the back of the room, where they can be absorbed, diffused, or re-directed in order to fit the "20/20" criteria(20ms & -20 dB), or the 15/15 criteria.

So all that you really need to do is to ensure that the length of any first reflection path is at about 20 feet (or more) longer than the direct path from speaker to ear. In a normal rectangular room, if your ears are more than 10 feet from the rear wall then you already complied with that condition. In your room, I'm not sure what those distances are like, but it looks like you might be OK there. That's why I asked (a few posts back) what your path lengths and times were like.

The second part of that "20/20" criteria, is the "-20dB" bit, which means that even when the reflections do eventually get back to you rears, they are 20 dB quieter than the direct sound. So you need thick absorption on the rear of the room in order to help accomplish that. Use something that has a coefficient of absorption greater than 0.9 for all of the frequencies you are interested in. Make that absorption thick, and space it away from the walls, and you increase effectiveness.

If you room is big enough, then diffusers are another option, since they "scatter" the energy in both time and space.

I'd be thinking along those lines.


- Stuart -