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

[Shybird]

Ahhh thank you for the reply Stuart!! Seriously I don't know how you keep up with so many threads...it's quite an incredible feat if you ask me.

I began the 3D today and I'm begininning to get very excited seeing it come together!!

Also starting to see more and more details that I had not gotten to yet...which means I will have MANY more questions soon...I will try to find the answers on my own the best that I can before I post with an update. This next phase is even more exciting than I had anticipated!

Basically a couple of metal brackets joined by a rubber decoupler in the middle. You attach one side to the top of your isolated wall, and the other side to your original structure. Provides structural support. It keeps the wall more stable mechanically, but isolated acoustically.

Cool! That helps me understand why those would be useful haha.

Probably a good idea. You could even ask him about moving to 24" OC, instead of 16" OC: That might be an option.

That's mainly why I went with 2x6's...so I could go with 24" OC and reep the low end isolation benefits!

Well, "Bigger is better", as they say, but eventually you get to the point of diminishing returns, or the point where you are compromising something else so seriously that it makes no sense.

Also, think of this: How far off-axis is the ray that gets closest to your head? Trace it back, and see how much of an angle that makes, as compared to the acoustic axis of the speaker. If we are talking about being 5° or 10° off-axis, then I'd try to improve that a bit. But if we are talking about 75° off axis, then forget it!

Ok cool, well to answer your question then.. that particular ray is 51.7º off axis from the center point of the monitor. Based on your explanation, I feel like I'm ok to move forward with this control room design. Yea???

However, could you take a look at the polar plots I provided for my Event ASP8's? They seem to radiate at 90º all the way up to about 5000Hz however I don't really know if I'm interpreting the diagram correctly. If that is the case, should I be more concerned with the ray being that close (~1'3") to the mix position as it passes by?

Sorry to keep going on this...it's just really hard to find answers on this topic (we need a sticky called "Rules and Methods of a True RFZ" on this forum! haha).

Have you looked at Adam's? Big fan.

Yea! I have looked into some Adam's and even listened to a pair of the A7's which were nice but didn't really sound like an upgrade from my ASP8's ...I do want to hear the A77X though...they look comprable to the Focal Twin in terms of size anyways ( ). I just want to make sure that whatever I get is a substantial increase in performance over my Event's (which I really do like a lot). I will keep searching!

I've heard that that happens to some people as they "pass over to the other side".... But you probably don't want to wait that long to build your studio!

Hahaha yea definitely want to get the ball rolling before then.

Thanks a ton man.. as always

Trevor

[RJHollins]

If you get an opportunity to audition the Pelonis monitors, please post back.

I too, recently, found out about them ... though not found anyone in town that has them

.... anyway ...

The transition to 3D can be very helpful. I spent weeks looking, spinning, zooming .... and designing down to the tiniest aspect I could.

The best part ... when it came time to physically build, it was like Deja-view

AND ... working the 3D, I was able to tweak, test, modify without wasting materials.

Sure ... building in reality will always bring its' own surprises ... like, gee ... I thought those concrete walls were square ... yeah, 'cept the wall section near the floor might have a slight bulge that ya never noticed before

Also ... being able to show my contractor & helpers what was to happen [after stamp of approval from staff 'Gurus'] made it 'easier' for these guys to understand. And believe me, even with the best intention ... these guys will think your nuts [that is why I've considered turning parts of my build thread into a type of Comedy script. [... I must say, I had some really quality on-sight workers]. You'll see it in my build thread as I tried to educate myself, along with the 3D. It help cut down on the number of 'Deer in the headlight' looks that were prevalent. [Remember ... these guys know how to build some incredible structures, but most have only a 'this should work' idea on building a 'sound proof' room ... cause they don't get to do that. BTW ... some of the Gang has returned for a visit and listen... and they are quite proud of what they were apart of, and thanked me for the experience ... and jaws hitting the floor with staring into the sound field ... man was I happy for them to experience sonic joy.

Heh ... sorry for chewing up your bandwidth ... just excited for you and look forward to the artwork!

Sincerely.

[Soundman2020]

However, could you take a look at the polar plots I provided for my Event ASP8's? They seem to radiate at 90º all the way up to about 5000Hz however I don't really know if I'm interpreting the diagram correctly.

Yes, but read the DECIBEL scale too! Look at the "800Hz to 20 k" plot. At 90° off axis, all of the mids and highs are AT LEAST 12 dB down: 8 kHz is -18, 10kHz. is -24, and everything above that is off the scale! So none of that is an issue at all.

You say that your "worst-case" ray is around 52°: at that angle, everything above 10k is down to at least -12db already. 10k is very much ray-like still, so all of your very high end is 15 inches away from your head, and also 12dB down. Even 2k is nearly 10 dB down at 52°. (Way down at 800 Hz you are still -6 dB, and that's well into the low mids there). Take this to a ridiculous extreme: even 100 Hz is more than 3 dB down, and there's no way that 100 Hz acts like a ray! So no matter what angle you get down there it would be irrelevant.

For the sake of being pragmatic, lets split this right in the middle of the spectrum: 1 Khz. Let's say, for argument's sake, that everything above 1K acts like a ray, and everything below 1k acts like a sphere (of course, that isn't they way it actually works, but just for the purpose of illustrating, pretend that it is) Now look at everything above 1 k on the polar plot: The next data point upwards is 1600 Hz. At 52° that is around -8dB, as near as I can tell. OK, so what was the minimum criteria for RFZ? "No reflections arriving at your ears until 10 ms after direct sound, and at least 10 dB down". So that 1.6 k "ray" is leaving the speaker already 8 dB down. It has to travel a distance (losing some energy), bounce off your surface (losing some energy) then travel another distance (losing some energy). It loses energy on its travels, since air itself attenuates slightly, and the "bounce" is not perfectly elastic either. So by the time it gets to the closest approach to your ear (15 inches away), it is very likely another 1 or 2 dB down: Bingo! We hit -10dB, the "magic" number! If you put some absorption on that first reflection point, you could easily knock a few more dB off that. Anything with a coefficient of absorption of at least 0.5 at 1.6 kHz. is going to knock enough energy off to put that "ray" down at -15dB by the time it passes your ear, and even then it is 15 inches away.

So your absolute worst case scenario is this: if you are mixing, and you lean way over to the left far enough to already be falling off your chair, you might just, possibly, maybe hear that hypothetical "ray" at a level that is well below the minimum threshold for RFZ, except that it might still be inside the 10ms time window.

To that, I'd say: no big deal. Not sure about you, but I rarely try to mix while I'm falling off my chair!

Could you make it better? Probably. You might be able to get to 60° off-axis at 24 inches from your ear and -20 dB, if you really try. Just maybe. Is it worth doing that? I very much doubt it! What else might you have to sacrifice to get there? It might be a lot of effort for little or no return, in real terms.

Personally, I think you've done a great job to get where you are, and I know you must have spent many, many hours on that, fiddling angles and distances and things, tweaking a half degree here, a 1/4" there.... I know how that goes. Been there, done that! Many times. So that's why I say that you've done a darn good job getting to where you are, and I really don't think you would make a huge difference by trying to tweak it more. Would moving that ray another inch out, or another degree over be worthwhile? No! You need to make BIG changes to make it worthwhile now. Look at the polar plot: To make a real difference, you'd need to get the entire top end out beyond 65°, and that is going to be really hard to do. Can you angle your surfaces those extra 7 degrees that you'd need, without messing up something else? I doubt it.

So I reckon you are fine where you are, and you've already taken it way further than most people ever would. And there are limits to what you can do in a small room! If your floor area of your control room was 50 m2, I'd suggest that you keep on trying, but with your size room I think you've got it about as good as it is going to get.

Maybe others might disagree, but personally I reckon there's not much point in trying to tweak things further. Really!

- Stuart -

[Shybird]

Thank you guys for the replies!!

RJ...

If you get an opportunity to audition the Pelonis monitors, please post back.

I definitely will let you all know what I end up trying out. These are really intriguing because of the price point and the externally housed power supply, as well as the fact they apparently hold their own against more expensive monitors. But yea...I don't know how to go about auditioning all these speakers. No one has them.

The best part ... when it came time to physically build, it was like Deja-view

That's what I'm hoping for!! haha.. it would definitely be nice to feel like I'd already "built" it before actually building it!

Heh ... sorry for chewing up your bandwidth ... just excited for you and look forward to the artwork!

No need for apologies! I really appreciate the input...it helps boost my moral to keep moving forward!


Stuart...thank you for such a detailed reply. That was extremely helpful..

Yes, but read the DECIBEL scale too!

HA...funny I would miss that little portion of the graph...

You say that your "worst-case" ray is around 52°: at that angle, everything above 10k is down to at least -12db already. 10k is very much ray-like still, so all of your very high end is 15 inches away from your head, and also 12dB down. Even 2k is nearly 10 dB down at 52°. (Way down at 800 Hz you are still -6 dB, and that's well into the low mids there). Take this to a ridiculous extreme: even 100 Hz is more than 3 dB down, and there's no way that 100 Hz acts like a ray! So no matter what angle you get down there it would be irrelevant.

For the sake of being pragmatic, lets split this right in the middle of the spectrum: 1 Khz. Let's say, for argument's sake, that everything above 1K acts like a ray, and everything below 1k acts like a sphere (of course, that isn't they way it actually works, but just for the purpose of illustrating, pretend that it is) Now look at everything above 1 k on the polar plot: The next data point upwards is 1600 Hz. At 52° that is around -8dB, as near as I can tell. OK, so what was the minimum criteria for RFZ? "No reflections arriving at your ears until 10 ms after direct sound, and at least 10 dB down". So that 1.6 k "ray" is leaving the speaker already 8 dB down. It has to travel a distance (losing some energy), bounce off your surface (losing some energy) then travel another distance (losing some energy). It loses energy on its travels, since air itself attenuates slightly, and the "bounce" is not perfectly elastic either. So by the time it gets to the closest approach to your ear (15 inches away), it is very likely another 1 or 2 dB down: Bingo! We hit -10dB, the "magic" number! If you put some absorption on that first reflection point, you could easily knock a few more dB off that. Anything with a coefficient of absorption of at least 0.5 at 1.6 kHz. is going to knock enough energy off to put that "ray" down at -15dB by the time it passes your ear, and even then it is 15 inches away.

All I have to say to that is wow! Thank you for the explanation. My friend was reading over my shoulder when I was first reading your reply and he was just like..."damn that's some upper level shit" haha...I got a kick out of that.

I do have one question though...could you point me to some outside reading material (or a chapter in MHoA) that explains the behavior of sound throughout the frequency spectrum? You keep talking about sound either as rays or spheres, and though I understand what you mean, I don't know where in the spectrum it begins to cross over from one type to the other (I'm assuming it's a gradual spread). It would be good for me to understand this concept a little more in depth.

To that, I'd say: no big deal. Not sure about you, but I rarely try to mix while I'm falling off my chair!

So I just have to avoid falling off my chair while mixing...I think that will be doable!

Personally, I think you've done a great job to get where you are, and I know you must have spent many, many hours on that, fiddling angles and distances and things, tweaking a half degree here, a 1/4" there.... I know how that goes. Been there, done that! Many times. So that's why I say that you've done a darn good job getting to where you are, and I really don't think you would make a huge difference by trying to tweak it more. Would moving that ray another inch out, or another degree over be worthwhile? No! You need to make BIG changes to make it worthwhile now. Look at the polar plot: To make a real difference, you'd need to get the entire top end out beyond 65°, and that is going to be really hard to do. Can you angle your surfaces those extra 7 degrees that you'd need, without messing up something else? I doubt it.

So I reckon you are fine where you are, and you've already taken it way further than most people ever would. And there are limits to what you can do in a small room! If your floor area of your control room was 50 m2, I'd suggest that you keep on trying, but with your size room I think you've got it about as good as it is going to get.

Maybe others might disagree, but personally I reckon there's not much point in trying to tweak things further. Really!

Thank you for the kind words of encouragement Stuart...that makes me feel a lot better about where I'm at.

Off to the 3D! Update coming soon...

Thanks guys once again...I really can't say it enough!

Trevor

[Soundman2020]

All I have to say to that is wow! Thank you for the explanation. My friend was reading over my shoulder when I was first reading your reply and he was just like..."damn that's some upper level shit" haha...I got a kick out of that.

Well... ummm... thanks! (I think?!)

Of course, that was just a rough and probably over-simplified analogy, to try to get you to move on and not fixate and things that you probably can't improve much. But the basic concept is right.

I do have one question though...could you point me to some outside reading material (or a chapter in MHoA) that explains the behavior of sound throughout the frequency spectrum? You keep talking about sound either as rays or spheres, and though I understand what you mean, I don't know where in the spectrum it begins to cross over from one type to the other (I'm assuming it's a gradual spread).

Hmmmm... Good question! Let me see if I can find something theoretical on that. There isn't really a point where wave propagation changes over from being "ray-like" to being "expanding-sphere-like". It's more of a gradual transition across the entire spectrum, where a 20kHz tone is practically all "ray", and a 20 Hz tone is practically all "sphere". You can even see that to a certain extent in the polar plots for your own speakers (albeit for different reasons). You can see that the 20 kHz contour is very much ray-like, while the 100 Hz contour is not in the least ray-like, and is almost perfectly spherical. That's due to the speaker itself, to a certain extent, but also to the nature of sound, and also to the dimensions we are talking about.

There's also the issue of scale: Sound waves are not affected by objects that are much smaller than their own wavelength, and are affected by objects much larger than their wavelength. So even a high frequency tone won't reflect too well from a small surface, just a half inch wide, while even a very low frequency tone certainly will reflect from a big enough surface, such as the face of a large building or a cliff. So there is a relationship between the size of the room, and the frequency, and what you can consider to be a "ray". or not a "ray" While a 500 Hz tone (for example!) might behave as a spherically expanding wavefront in your room, in a huge concert hall it might behave more like a ray, simply due to the relative sizes.

So there is no single point where you can say "Above xxxx Hz sound always behaves as a ray", or "Below yyy Hz it is always a spherical wavefront". It just isn't that simple. Sorry if I gave you the impression that there is such a point: there really isn't. It's just a progression of "more ray-like" and "less ray-like".

The only tid-but I found in my "file of interesting stuff" is a comment from an unidentified source that says "At a frequency of approximately 11,250(RT60/V)^1/2, wavelengths become comparable to the dimensions of the room" (V=volume), so around there is the point where ways start behaving more ray-like.

There's also a hint of this in Bob Gold's famous room-mode calculator, where he lists the point at which sound starts acting more like "spectral reflections", but I'm not sure what equation he uses to arrive at that.

I'll see if I can find something more theoretical on this for you. It's a fascinating part of acoustics, and rather blurry.


- Stuart -

[Soundman2020]

Ahh! Found something interesting on-line, from the university of Santa Cruz:

"Sound waves only behave as rays when the wavelength is small compared to the surrounding structure. This is affected by the volume and reverb time of the room. You can work out the lower limit of frequency with the formula:

ray-cutoff-frequency.png

"( http://artsites.ucsc.edu/ems/music/tech ... Modes.html )

That's the same equation as above, of course, stated in a different form. I'll see if I can track down the derivation.

Interesting that it is related to RT-60 times, not just frequency. So you can actually change the transition by changing your room treatment...

- Stuart -

[Shybird]

Stuart, I'm so sorry for the late reply...all I can say is WOW!... thank you so much for your time and effort on those answers! I must say that even "MIND BOGGLING" does not describe your answer haha...

Anyways, I moved on to 3D land (finally!) for layout 14.5 and got through the basic framing of the whole place (which looked so cool btw) and took some time playing with the camera to see what the sight lines were like from the actual human perspective (or at least as realistic as sketchup will allow)...I then realized that the sight lines from the mix position into the live room were really bothering me because the mix position felt too far forward in relation to the sliding glass doors.

SO I played around with things for a while longer until finding yet another "happy medium". I was able to fix the problem enough to satisfy my nit-picking self, without subtracting too much from my primary goals. I won't go into details too much here as it really isn't enough of a difference for anyone to care. I will post the updated 2D along with the 3D whenever that gets closer to done.

For now though, my only question is regarding the ceiling of the RFZ in the control room. I took it into 3D and found that a 25º angled ceiling, where the slope starts at the midpoint of the sliding doors, allows for rays 80º off-axis to be 1' 3" over the ear (this is with the acoustic axis 4'6" off the ground). The dotted line closest to the circle (head) is the 80º ray I'm speaking of here.

Is this overkill?

If it is no more expensive to build with the steeper angle, it seems like it would be worth it. It makes the lowest ceiling height somewhere around 8'10" (the highest being about 11'4") which is stil pretty tall. Should I go even steeper to the point that even at 90º off axis the ray will still go over the mix position? haha that's probably ridiculous but I've seen some RFZ style rooms with very steep front ceilings. So I thought that might be what they were doing there.

Well that's it for now...let me know if you need more pictures or something, or if you want me to post the updated layout.

Thanks a ton fellas
Trevor

[Soundman2020]

Is this overkill?

80° off-axis? Ummm .... YES! I sure hope I never get to go rabbit hunting with you one day! I can just imagine you dragging along your bazooka to do the job....

Your ceiling is fine, and you'll have a cloud up there anyway, so ray-tracing 80° off axis does seem to be a bit more than necessary.

On the other hand, you seem to be missing the 800kg gorilla in the room, and this is gonna get you tearing your hair out. You are looking up, but forgetting to look down, where the real problem is: The top surfaces of your console and desk are very flat, massive, and highly reflective, and very close to both the speakers and to your ears. Ray-tracing those is gonna give you nightmares....



- Stuart -

[Shybird]

Haha thanks Stuart...I knew the jokes were coming soon...I just forgot how quick you reply!!

And in regards to the gorilla, I had thought of those reflections to certain extent but since I don't exactly know what type of studio desk will be in the room... how do I predict the reflections?

And more importantly, I am confused as to how these reflections can be avoided. I honestly thought that in a room this size, desk reflections were just something you accounted for when eq-ing the monitors. Whooo I know I'm probably showing my ignorance on this one.

I've dropped the bazooka and I'm now running for the hills..................................

[Soundman2020]

I had thought of those reflections to certain extent but since I don't exactly know what type of studio desk will be in the room... how do I predict the reflections?

You already have your console, I assume? If not, then now would be a good time to decide on what console you want for your room. So figure out the the angle of the top surface of the console, figure out how high it will be above the floor (assuming normal desk height), and work from there.

If you won't be using a console (ITB only), then just use use your best guess of what the height of the upper surface of the desk will be. Probably in the range 27" to 30": Use the highest possibility, and work on that. If the actual desk ends up with a lower height, that will only improve things, so work from the biggest number.

Or design your own desk, with the best height and shape for the least early reflections.

And more importantly, I am confused as to how these reflections can be avoided.

same as you did for the walls and ceiling: change the position / shape / angle / size until the reflections are tamed enough. If you have a console, then you can tilt it more towards you, thus moving the reflections down. Etc.

I honestly thought that in a room this size, desk reflections were just something you accounted for when eq-ing the monitors.

There will always be reflections, yes, but you can't EQ those out of your monitors very well! There will be phase cancellation, comb filtering and other nasty stuff going on, and EQ cannot solve those issues. Yes, some speaker manufacturers do put controls on their products and talk about how you can tweak the mid-range to deal with desk reflections, but that only disguises the issue a little bit: it does not get rid of it: It might sound a bit better, but the problem is still there: If you break your leg (perhaps from carrying your bazooka while rabbit hunting! ), you can take an aspirin to take the edge off the pain so you don't notice it so much, but it won't cure the broken leg, and you still won't be able to walk on it.... EQ cannot fix phase cancellation, and it cannot fix comb filtering. They will happen at any hard boundary: the trick is to stop them getting to your ears.

By carefully angling things you should be able to keep those guys reasonably well away, but if not there is also the final, worst-case kludge solution: vertical reflective panels on the far edge of the desk, to prevent those bad guys from ever hitting the desk / console. Probably not necessary, and it does introduce further problems of its own, but it might be a possibility.

Or you could just live with the artifacts! But seeing how you've attacked this whole design things so far, I don't thinly you'll be happy with that! No rabbit is ever going to get away form your bazooka!

I've dropped the bazooka and I'm now running for the hills

Yeah, but you're just running to pick up that cruise missile sitting over there on the hills...

Seriously, desk reflections are a problem, and you should be able to tame them enough if you play around, with desk and console surfaces, but you most likely wont be able to get it perfect, and certainly not out to 80° So the idea is just to get it as good as you can.

- Stuart -

[Shybird]

If not, then now would be a good time to decide on what console you want for your room.

Ohhf...I wish I had a console to throw in there...unfortunately I don't think I will be able to determine that yet. For now I will be completely ITB and just use my Onyx 16 channel plus a few pieces of outboard gear. I know, it's kinda ghetto compared to the studio it will be used in. BUT my plan is to grow into the space...

Or design your own desk, with the best height and shape for the least early reflections.

We are planning on using some wood from the silver maple (the one that's getting chopped) and having a friend of ours make a custom desk. He's made a coffee table and chair for us before out of some walnut he had...it's absolutely beautiful work with a lot of the natural wood edges and no visible joints. Very solid stuff. I would love to see that tree get used for some studio furniture.

same as you did for the walls and ceiling: change the position / shape / angle / size until the reflections are tamed enough. If you have a console, then you can tilt it more towards you, thus moving the reflections down. Etc.

Makes sense.

Or you could just live with the artifacts! But seeing how you've attacked this whole design things so far, I don't thinly you'll be happy with that! No rabbit is ever going to get away form your bazooka!

Damn right! We really should go hunting...haha

Seriously, desk reflections are a problem, and you should be able to tame them enough if you play around, with desk and console surfaces, but you most likely wont be able to get it perfect, and certainly not out to 80° So the idea is just to get it as good as you can.

This is not something that effects monitor placement though...correct? The height of the monitors is somewhat fixed unless I decide to angle them downwards right? (which I'm not wanting to get into honestly) Just making sure it has more to do with the actual placement, size, and angle of the desk and only the desk...please correct me if I am misunderstanding.

Really appreciate your perpetual help Stuart...thanks a ton

Trevor

[Soundman2020]

This is not something that effects monitor placement though...correct? The height of the monitors is somewhat fixed unless I decide to angle them downwards right? (which I'm not wanting to get into honestly) Just making sure it has more to do with the actual placement, size, and angle of the desk and only the desk...

Exactly. In fact, raising your monitors and tilting them down would make the console reflections WORSE: Think about how angles and reflections work... the reflections would hit you higher up. So keeping your monitors where they are, and not tilting them, is a good thing.

- Stuart -

[Shybird]

Exactly. In fact, raising your monitors and tilting them down would make the console reflections WORSE: Think about how angles and reflections work... the reflections would hit you higher up. So keeping your monitors where they are, and not tilting them, is a good thing.

So the easy way is best way...awesome!!! That may just be the best thing I've heard in a while...usually it's "oh well yea kinda but it's really not that simple". haha.. feeling lucky on this one.

[BriHar]

If you don't have a big mixer taking up most of the desk space, then best to keep it as cluttered as possible.

[RJHollins]

If you don't have a big mixer taking up most of the desk space, then best to keep it as cluttered as possible.

oh .... I like that !