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

Any opinions on this design? I am having a hard time deciding between the two (12 and 13 that is)... :| Been reading more in the MHoA...the section on modes within splayed walls is scary to me!! Makes me want a nice and easy rectangular room built to a tested ratio! haha... I'm mainly worried about the asymmetrical section at the rear end of the CR in layout 13. Seems like it might cause problems attaining an even distribution of modes based on "my" understanding of the reading . And there's no way to test it beforehand! I'm becoming haunted by acoustics...day and night! Stuart, I know you had said a notch like that wouldn't be an issue as long as the front was symmetrical. Any change of heart in that regard? Also do you think the CR in layout 13 could sound better than layout 12 since it upholds a true 20ms RFZ? Or am I splitting hairs? Also any thoughts comparing sight lines? Flow? Comfort? Ahhhhhhhh so many compromises every which way. I really like certain aspects of both designs. Thank you all for getting me this far in the journey...I'm just ready to find "the one" and settle down! But there's so many fish in the sea... :? (speaking of designs here :) ) Trevor

Both of those like like they will work fine. You have good sight lines in both, nice size and shape of spaces, etc. I wouldn't worry too much about the modal issue: Everest also says that for rooms that are only slightly non-rectangular (such as yours) you can estimate the modal behavior by averaging the dimensions. Besides, modes can also be attenuated with suitable treatment, and a recent study I read on hundreds of high-end control rooms around the world implies that many of them do have modal issues, to one degree or another. So don't get too hung up over "golden" ratios and "perfect" modal spread: Even if they are spread perfectly, they still need damping!

I'm becoming haunted by acoustics...day and night!

He he he!! Welcome to the club! You are now fully qualified to design and build your studio..... :)

Stuart, I know you had said a notch like that wouldn't be an issue as long as the front was symmetrical. Any change of heart in that regard?

Perfect symmetry all around is great if you can get it, but the most critical part of the room is the front half. That's where the first reflections are happening, where your ears are, and where the speakers are. Further back is where major absorption and secondary reflections should be going on, with those also being directed into absorption, or diffusion. The concept is to have only a direct sound field in front of you, and develop only a diffuse sound field behind you. If it can be evenly diffuse, then great. If not, then aim to attenuate it as much as possible. Your offset at the rear won't make it 100% "evenly diffuse", due to the lack of symmetry but is sure does look like you plan to kill the entire back end with major, deep absorption: From the shape, I'm guessing that you are thinking of hangers and superchunks back there? Good choice. You have enough space, so that should work well. In fact, you might even be over-doing the absorption back there! That's not just killing a few lows a bit: that's a downright murderous massacre of the entire spectrum going on back there!!! Now, if you are REALLY concerned about the rear end of the room, and would love to make it "perfect", then just slide the bathroom over a couple of feet, and continue that left wall all the way back at the same angle: It should end up more or less where the toilet is at present, so you'd have to slide the bathroom over by maybe 2 feet. And if you really wanted to be even more perfect, you could angle the entire rear wall to be parallel to the front wall, or maybe just angle the left half, but either way making the room totally symmetrical again. (That would open up a small triangular space behind the control room, which you could maybe use for a strangely shaped closet in the bathroom...)

Also do you think the CR in layout 13 could sound better than layout 12 since it upholds a true 20ms RFZ? Or am I splitting hairs?

They way you have that laid out and what I'm assuming is deep bass treatment on the rear wall, should give you excellent RFZ. That rear end looks like it will be very dead, and you'll probably have to tune that to not kill the highs too much, but it certainly looks like you are ticking all the right boxes. However, having said that: 20ms for the Haas effect is only an average estimate for the general population of humans on this planet. For some people, 20ms is just fine, for others as little as 10ms might be good, while still others would still not be getting it at 30ms. So yes, shooting for a perfect 20ms is maybe splitting hairs a little. If it was 19 or 18 it would probably still be good, and I've seen some recommendations saying that a "15/15" criteria is still acceptable for studios, for most people (15dB down, and 15ms late). So this is like ratios: there's no such thing as "perfect", so just get it as good as you can.

Ahhhhhhhh so many compromises every which way. I really like certain aspects of both designs.

OK, that settles it! You are most definitely qualified now! You have passed the final test for home studio design, and you'll be receiving your decoder ring and instructions on the secret hand-shake by mail next week.... ! :) Seriously, I think it's time to stop sweating these things too much, and start fleshing out your model now, so you get yourself even more confused as you take things into 3D, and start designing your treatment, HVAC, electrical, door seals, etc.... :) - Stuart -

Thanks for the reply Stuart!! Your input always helps me keep moving forward! Here is the updated layout. I'm liking the CR better now that it is completely symmetrical from front to back (I think now I can sleep at night :lol: ). I have some questions regarding the bathroom walls, however I don't see much need to get into it right now since I haven't begun the 3D for this layout. It's mainly an issue of what to connect the RC to in that space where there is no framing behind the back left wall of the CR. I think this might be the one. After fixing the CR, I was surprised to find that I only lost about a foot of length on the storage room. Also, there is a great place for some storage in the bathroom where that angled wall is. Does that look like a more reasonable depth of hangers/absorption on the rear wall? It's 2'6" from the middle point...and a little less than that once it reaches the side walls (about 1'8"). I realize this is not that important to figure out exactly right now, but at least I have a good place to put some hangers!! I'll post more soon...heading to a friends birthday celebration. Happy Thursday!! And thanks again for all the help. I'm feeling better now... :) Cheers Trevor

Hey Stuart...my builder presented a slight concern for the 1" gap between the inner walls...is it ok to do this? Have people been successful with only 1" between adjacent wall frames in a double wall structure? If I go more than 1" then I will have more than a 12" air gap which you had told me would not be necessary... Just wanted to ok this small detail since I am now going to work on the 3D...and since sketchup is so hard to reverse and make changes I just want to get it right the first time...or at least as close as possible. Thanks Trevor

my builder presented a slight concern for the 1" gap between the inner walls...is it ok to do this?

Why is he concerned about that? Is there some specific issue about it that worries him? Maybe something to do with your local building code? Also, you are building your walls "conventionally", and not "inside-out", right? If you were doing them inside-out then you'd need more space to fit in two layers of 5/8" drywall and to get an air gap over 4", but for conventional construction a 1" gap between frames will leave you with nearly 9" of air gap. Unless you need very high levels of isolation down to very low frequencies, I don't see a problem with that. Of course, increasing the gap will help with isolation, for sure, but it also eats up floor space inside your rooms... (I'm assuming 2x4 framing here: if you are using 2x6 then the gaps are even larger). Maybe your builder could be more specific about his concern? - Stuart -

Hey Stuart thanks for such a quick reply... He has never built double walls so he was just worried about it being too close to even build (I guess 1" just doesn't sound like much room for error to someone who's never built double walls)...but honestly I'm not really sure what exactly he was worried about (I'll have to ask him again)...it doesn't seem like 2" would make it any easier though. Anyways, I am using 2X6 studs for the inner walls with 24" OC....that's what is represented in the 2D sketchup. With a 1" gap, that will give me a total of 12". Thanks for the reassurance...I will continue with 1" since it is all I need. Cheers Trevor

Ahhhh....I have some very unfortunate news regarding layout 13.1...it's not even close to a proper RFZ because I overlooked the reflection points on the side walls at the front of the room. The splayed walls are not steep enough to deflect the sound to the back of the room. :oops: :cry: :x I feel so stupid to have missed this!! Ahhh I was about to start working more on the 3D but decided to double check my reflection times one last time and that's when I realized my oversight. Anyways...on to more designs...yet again. :( I thought I finally had it!! So frustrating... Out for now (and by out, I mean banging my head against a wall :| ) Trevor

Ooops! - Stuart -

Ok... Once again I'm back with a new design! Haha Alright so here it is...basically just an adaptation of the last one. After spending a lot of time trying out alternate footprints with the concrete, this basic rectangular footprint still works out the best for what I need. It also avoids having more than one roofline. This will help out on the cost and speed of construction of the outer shell...so I'm sticking to it. Realize though, it is slightly different considering the last one was a perfect square but it remains approximately the same square footage. Some thoughts/questions: -After calculating the RFZ, it comes out to a little over 20ms! (in a 233sq ft. CR) -How far behind the engineers head should the closest reflections from the side walls be? What's the safe zone? -Do the baffles of the soffits count as the reflection surface when calculating the RFZ? Or do you have to think of them as "invisible" and calculate using the angle of the drywall behind? I'm assuming that standard soffits are constructed in such a way that they will reflect the frequencies needed for an RFZ...but I wasn't sure so I'm asking. (this applies to the left speaker reflecting off the right baffle and vice a verse) -Is 5'5" too close for the direct signal hitting the ears? I think 6'5" is what I remember the recommendation being... Alright that's it for now...let me know if you see any major problems or if you see a better way of doing the CR. I've gone through many options. I've also been trying to reach Event about some specs on my monitors but have had zero luck....arghh!! It's been a solid 4 days now. Hopefully I'll find out soon. Thanks in advance! Trevor

Hi Shybird, Been following along on your design. As you well understand how important the designing stage is ! If I may ... this is something that brings up a concern :roll: It has to do with the walls in the bathroom area. It's difficult to clearly see what the structural layout is in that area of the design [from the posted floor plan], but the 'concern' has to do with how the bath area is being framed off, AND, more importantly, how the isolation walls are being displayed. It appears as if there is only a single stud wall separating the bath from the backside of the control room, and the same issue into the main room ?!? I would be very interested in reading what the 'experts' have to say on this. Just trying to lend a 'critical' eye if it helps !!! :)

Hi RJ...once again thank you for the comments. Sorry it's tough to see the walls in the image there...but I have drawn in a resilient channel that will help the bathroom remain as part of the outer shell (decoupled from the live room and control room). Stuart addressed this with me earlier in the thread. I am trying to save money on the bathroom and mechanical room and don't plan to do a complete "room within room" construction in those places. I am aware that the isolation will not be nearly what it is between other rooms. I'm ok with this at this point. If for some reason there is room left in the budget (highly doubtful) we might shoot for more isolation. Cheers Trevor

Here's two more with slight modifications. I think I'm liking Layout 14.1 the most so far. It has great sight lines between all rooms and has just enough additional space in the CR to make it appear more comfortable. What do you guys think? Any opinions on the designs? Any preferences between the three? Thanks a ton! Trevor

Any opinions out there?

With both of those, the rear sections of the side walls seem to be non-parallel (which is fine), but they seem to be angled the wrong way, making the room narrower at the back wall than in further forward (which is not so fine). The room should only get wider as you go back, or stay the same width. It should not get narrower. The right side should be easy to fix: you have some space behind that wall. But the left side looks like you might need to angle the bathroom wall a bit, to match. - Stuart -

Hey Stuart, I can fix this...however I'm a little unsure why the room cannot angle inward like that past the mix position...it doesn't effect the reflections for RFZ in a negative way (unless I'm missing something) so I did it to allow the bathroom wall to be straight. Does it have to do with modal distribution? Or clarity of sound at the couch position? I'm really stumped on this one... Thanks again for the input Stuart...I want to get this 2D finalized as soon as possible. We are moving forward on the tree removal soon as well as adding a huge gate to the fence for construction access and future studio access. cheers Trevor

Also, do you have any input for the questions posted along with layout 14? I really need to know if I'm designing/calculating the front half of the CR correctly. Does layout 14.2 comply with what you are saying about the back half of the CR? It angles in only a little bit at the very back...is even that much not acceptable? Thanks Trevor

Here is a John Sayers design that appears to do what you are talking about in the rear of the CR. http://www.johnlsayers.com/Studio/Mainpage/MP-Carriage.htm What is the acoustical difference between that design and one like mine (14.1) where those angled rear walls extend up a little further into the room? I really need to understand this concept!! I'm sorry but I'm really confused on this one... :? Trevor

Hey Stuart...here is another one that demonstrates similar "inward" angled rear walls. Can you see why I'm confused?? :| http://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=1929

Can you see why I'm confused?

Yep! :) OK, I'm not saying that you absolutely cannot reverse the angles at the rear. What I'm saying is that it can be a problem if not done thoughtfully, and it also eats up space that could be put to better use. Every cubic foot of volume inside a room helps a tiny bit, acoustically. But a cubic foot inside the wall doesn't do a lot! And more angles means a bit more complication in construction, too (a practical issue, not an acoustics issue). But there is one more big point here: both of those studios you linked to are 5.1 studios, but it doesn't look like yours is. Yours seems to be a normal 2.0 setup. 5.1 brings some interesting new factors into the equation, like first reflections from the rear speakers happening behind you, off the back walls, not in front of you, space for the rear soffits, and suchlike. There's probably not too much of an issue in your case, and I'm sure you ray-traced all of that meticulously, so you are probably fine, if that's the way you want to go. - Stuart -

Hey Stuart thanks for the reply...that makes sense to me now. Can you answer my three questions regarding the front half of the CR?? I need clarification here to know that I'm on the right track. 1.) How far behind the engineers head should the first reflections from the side walls intersect? What's the safe zone? 2.) Do the baffles of the soffits count as the reflection surface when calculating the RFZ? Or do you have to think of them as "invisible" and calculate using the angle of the drywall behind? I'm assuming that standard soffits are constructed in such a way that they will reflect the frequencies needed for an RFZ...but I wasn't sure so I'm asking. This applies to the left speaker reflecting off the right baffle and vice a verse (I provided a picture below to demonstrate what I'm referring to here). 3.) Is 5'6" enough distance between the ear and the speaker (direct signal)? And is 5'5" enough space between the engineer and front glass of the CR? Getting closer I think...I really appreciate all the help. I think there should be a sticky that demonstrates ray-tracing and RFZ design at a more detailed level. It would be a great help for us newbies! Trevor

1.) How far behind the engineers head should the first reflections from the side walls intersect? What's the safe zone?

Hard to say: depends on the Q (directionality) of the speaker, off-axis response, the angle, the frequency, etc. Probably a foot or so is about as close as you'd want to get, but two feet would be better. (I'm not aware of any actual research to back that up: just my own personal hunch.) BTW, is that a Sony console you have there? Kind of looks like it, but then again, it doesn't...

2.) Do the baffles of the soffits count as the reflection surface when calculating the RFZ?

Ohh yes! The front baffles ARE the new wall of the room, as far as the speakers are concerned. That's why you have to build them massive and rigid.

I'm assuming that standard soffits are constructed in such a way that they will reflect the frequencies needed for an RFZ...

Exactly, which means "as low as the speaker goes, and then a bit more, just in case". Their main purpose in life is to force the low frequencies (below the baffle step point) back into half space, so they have to appear very solid, very massive, very reflective to those low-frequency sound waves. Of course, that also means that they appear even more solid and reflective to the highs! Thus, they absolutely must be taken into account for your RFZ ray tracing.

This applies to the left speaker reflecting off the right baffle and vice a verse

Exactly. But take a look at your speaker manual, and specifically at the polar pattern (dispersion pattern, or whatever it is called: the one that shows you the SPLs around the speaker for each frequency range). You need to take that into account when you check your reflection angles, ray tracing, etc. For example, at 60 degrees off axis, you won't find very much 20 kHz at all, but you might find a lot of 200 Hz, for example. And just to confuse you even more, don't forget that highs bounce like light rays, while lows bounce like expanding balloons... :) So for lows you really should draw a cone that expands out from the point where the ray hits, and check how that cone is with respect to your ears... (Hey, I DID warn you that things are a bit more complex than they look at face value!) OK, put down the gun and suicide note, and don't sweat things too much: if your ray tracing gives you a couple of feet clearance all around your head, and the reflection point is a reasonable distance away, you should be fine. So go with the largest angle that gets things a few feet clear of your head, and that's about all you need to worry about.

I think there should be a sticky that demonstrates ray-tracing and RFZ design at a more detailed level. It would be a great help for us newbies!

That would be useful, wouldn't it? One day when I have time, I'll see if I can write up something... (Hmmm... checking my calendar, I should be able to fit that in some time in early 2058... :) ) What I would REALLY like, is a free plug-in for SketchUp to do all the ray tracing for me!!!! Oh yeah! (Well, dreaming is free, at least). - Stuart -

Stuart thanks so much!! That helps a lot...and yes, after that explanation, I was about to go find a wall to bash my head against.. :horse: :lol: Thanks for calming me down... Anyways, I added a third question to that post, but I think I must've done it while you were typing up that detailed reply...so sorry to trouble you once more but here's my, dare I say, final question for the CR... 3.) Is 5'6" enough distance between the ear and the speaker (direct signal)? And is 5'5" enough space between the engineer and front glass of the CR? Thanks!! Trevor P.S. The manuals for my Event speakers do not provide the information you are talking about :!: I've tried contacting Event by phone and email for over a week and have had ZERO luck!! Really bummed about this... Also, I just got that console off the 3D warehouse...I don't have a huge console. Just a Mackie Onyx 1640 and a MOTU 896HD. Someday I hope to purchase a console but for now I'll be focusing on buying more outboard gear and mics.

I'm asking question number 3 because you provided documentation earlier in the thread that stated the EBU recommendation was 6'5" from ear to monitor...so now I'm wondering if less (5'6") is a bad idea.

3.) Is 5'6" enough distance between the ear and the speaker (direct signal)? And is 5'5" enough space between the engineer and front glass of the CR?

It's fine. EBU recommends a distance of between 2 and 4m, (6'7" to 13'3", roughly), but you are close enough, I reckon. If you try to get another foot away, you'll be too far back in the room, I think, and/or the speaker angels/position will get a bit weird. You might be able to tweak things to gain a few inches, but you are not far off the ball park. And the EBU recommendation is for rooms that have have more than 325 square feet of floor area, which is also a bit more than you have. Rod has a very accurate rule of thumb for these situations. It goes something like this: "You have to live with what you've got." (My paraphrase). In other words, if that's the area available to you, then that's what you can do with it. It ain't Abbey Road, but it sure ain't bad at all! In fact, I think you've done a darn good job to get where you are already, and you are probably getting it to about as good as you are going to get it. That place is going to sound really good, I think. There's probably a bit of room for tweaking still, but it loos like you are at the stage where anything you move to make one aspect better, is also going to make another aspect worse. - Stuart -

Ahhh!! Thank you so much Stuart!! I think I'm finally seeing a light at the end of the 2D tunnel...I hope soon I will be starting my journey in the pitch black of... 3D :shock: First...I'm going to nail down this design and make all necessary compromises in order of priorities. I will post back when I think I've got it so I can get the "go ahead" on starting my 3D model...woo!! 8) I really could not have made it this far and this quick without you man! You've been an absolute life saver! Thanks a ton Trevor