Hi,
I found this forum several years ago and have lurked from time to time. I really love the architectural acoustics subject matter and read everything I can find on it. My new house has this neat room with inclined high ceiling, I've thought about the best way to turn it into a very neutral project studio for more than one year now. I've brought one contractor in to make a quote on the modest re-structuring I proposed and he's disappeared. Turns out I'll have to put on my Builder hat and do it myself. Ever since thinking about doing it myself I've started to question all my premises. It's causing me moderate but constant stress, it's getting to the point of being unbearable. Please advice me as you see fit.
Goals
Have a neutral sounding single room space, where I can record my own Singer/Songwriter material and mix it. I've had some moderate success doing Mastering work for some local bands and even if it's lofty as a goal, it would be great if the decisions are compatible with a space apt for Mastering (not classical music, local indy productions).
Where am I in the process?
Finally have a budget. Ready to begin building as soon as my conscience is clear that this is the best that can be done with the available structure.
The Room, as is
Is made of cinder blocks, with two coats of paint.
The ceiling is higher on one side. It has a slope, or incline.
The basic shape is a square that has been cut on one of its corners, leaving a non regular pentagon.
There are a lot of windows, currently. They all have a lower edge at 3’.
I’ve included a rough sketch of the room using roomstyler.com one in imperial and one in SI units. (SEE ATTACHMENTS)
The Design
(When describing "to my left" and "to my right" I'm mostly imagining sitting down at the desk mixing position.)
After much thought, I settled on a mix position facing the miami windows on the High ceiling side of the room. If I “fixed” the asymmetry behind the L and R speakers, at least I have solid walls as backing for some absorption treatment for the reflections dead center straight out my ears and also behind me left and right. I have available several batts of UltraTouch (3” thickness iirc) and something similar to Roxul sold locally for home theatre builds under the brand Blacks (2” iirc). And so, the way I’ve tried to meet this design challenge is this.
Premise: I can make a photocopy of the diagonal wall on my right, to my left, but using easy to build materials.
Premise: to make the new diagonal false wall to my left, I’d use cement board, instead of plaster/gypsum, since this way will be closer to the cinder block acoustic properties. I would use wood frame/studs, and sweat out the details regarding any resilent/flex channel, insulation or slats needed to “tune” that wall so that it is an acoustic replica of the cinder block one. Goal would be same STC same NRCs as possible, rrrrriiight? full photocopy.
This means that the new wall needs a Single Glass Pane window smack in the center as well. Since a window into nothing is not useful, I came up with the idea to build an embedded book-shelf in there, right behind the glass. I would have a triangular unused space behind this new diagonal wall; I’d set up an 8’ tall “superchunk” bass trap in there using a tower of stacked Blacks 2’ triangles. The new diagonal wall would be 10’ tall. Since the ceiling is 14’ tall on that end, I’d have space for an additional shelf up there, above the triangular false ceiling (at 10’) for the new false wall.
Premise: 10’ is a good height for the false wall.
Premise: the “superchunk” bass trap behind the false wall will go to work for my room if I cut-out some slats on the wall — or maybe leave the top open?
When doing sensitive listening, I could potentially “cover” those big square glass panes with one large absorber square each.
Premise: The absorber squares would be good value to the acoustics.
I plan to finish both walls by installing some wood paneling available here that includes prime root diffuser style squares.
Premise: assuming the panel is indeed manufactured diffuser-math-correct, covering both walls in the diffuser wood paneling would be good value to the acoustics.
Two 4’ W x 8’ H absorber panels round everything out on the far wall behind me at mix position.
Premise: I can't calculate this room's modes easily.
I’ve included a rough sketch of the design using roomstyler.com, one in imperial and one in SI units (SEE ATTACHMENTS).
For some reason the sketch doesn’t show the absorber material layout, and some framing columns I included for consistency. To see those you can take a look at the 3D rendering preview in the public profile of the design: https://roomstyler.com/rooms/14695980/i ... d2-vintage
If you’ve read everything and want to help me out with some solid advice, you’re a champ.
I am grateful for all the experience and advice you could offer, regarding design, construction materials and especially the stated Premisies I used on my analysis.
Best regards,
-m
Analysis Paralysis -- Advice on Design please thanks
Originally posted at johnlsayers.com, topic 20827.
Hi there " Mesmer", and Welcome! :)
Two quick points:
1) Photos of the actual room would help to understand the situation better.
2) It would be far easier to just orient the room to face the other way: Make the "bottom" wall the front of the room, with the angle behind you. You say the ceiling is inclined, but also high, so it would be simple to deal with that with a cloud or two. You didn't say how how the two ends of the ceiling are, or which way it is inclined, but assuming it is somewhat higher than a typical 2.4m (8 foot) ceiling, there should be enough space to deal with that. You did mention wanting to make your superchunks ten feet high, so I'm assuming that the existing ceiling is at least ten feet high: that's plenty. More than enough.
What you propose reduces the room volume considerably, wastes space, and creates surfaces that are angled too much.
Also, there's a number of big issues with some of your premises. Firstly, if you did want to build that wall on the left to match the wall on the right, then it would have to be sealed air-tight with no holes, slats or superchunks inside. Just wasted space. As soon as you cut any type of hole into it, it no longer matches the other wall, acoustically. So you can eliminate anything that needs holes in that wall: no slats, slots, superchunk, or anything similar.
Next, your room is too small to be able to use numerically-based diffusers, and certainly not on the side walls!
You need at least ten feet between the face of any numeric diffuser and your ears, and possibly more, depending on how the diffuser is tuned. Your room is not big enough to achieve that, so you can rule out using diffusion. You are limited to absorption and reflection only.
Also, you do not need to try to match the acoustic properties of the left wall to cinderblock: you'd never be able to do that anyway, for a very simple reason: The only material that matches the characteristics of cinderblock is something that has the same surfaced density and rigidity. You cannot match that with materials that are far less dense and far less rigid. But even if you could match it, you still don't need to. What is important here is that the walls should be roughly the same in terms of reflection, and plain old drywall, or MDF, or glass, or fiber-cement board, or plywood, or OSB, are all sufficiently close anyway, as long as you make them reasonably thick. And since both the left and right angled walls are at your first reflection points, you'll need to treat them with thick absorption anyway, which can be matched and identical. But this is all about your proposed scenario, which is not a good idea at all to start with, and not feasible acoustically anyway.
Finally, I'd really suggest that you should do your room layout in SketchUp, which is 3D. Sound is 3D, people are 3D, treatment is 3D, so there's not much point to trying to design your studio in 2D! :) SketchUp is free, and very powerful.
My advice would be to flip the room to face "down" the page, and set up your geometry correctly for that orientation. That would also allow you to flush-mount your speakers, and reap all the major benefits of doing that.
- Stuart -
Hi Soundman, thanks for a great reply, I feel welcomed already.
I will get on doing a 3D render asap.
And can provide Pics real soon too.
Regarding the ceiling height question, In the provided drawings the "bottom" as you call it is 9 ft high, while the "top" (where I originally put my mix position) is 14 ft high. It is a straight "ramp" or plane that connects that "back" and "front" (relative original) wall. I tried to indicate this with the blue arrow near the left of the drawing and I see it didn't work :oops: my bad. The 3D sketch can take care of that!
So if I read you correctly, it doesn't matter what sort of trickery I come up with to get the STC and NRC matching, the ears would "see" different sounds from left to right and so that mix position would be bad for mastering or anything requiring critical listening through balanced monitoring system. That's terrible news.
Also thanks for your pointers about Diffuser strategies, I didn't know you required a baseline distance but can see how it makes sense.
Finally, flipping the room will be a fun design exercise and will start working on it.
My main concern with that orientation is that the reflections coming in from the back of my head behind my left and right ears will be so different. Perhaps heavy handed absorption is needed then, on that new back-wall (which was in the original design the front wall). Another concern was that with the 14 ft high ceiling I had planned on not treating my "roof" at the mix position at all, and now at the 9 ft high end, as you mention I probably have to start looking at doing some kind of simple cloud install in there, which at an angle because of the ceiling might become tricky...
On the bright side, re-imagining the design to actually use that space which I was willing to let go, I get a feeling that there is space now to make one of those "Vocal walls" (?, don't know how to actually call those micro amphitheater looking, enveloping walls that work great for tracking a singer-songwriter with guitar and mic).
Ok, pics and 3d sketch coming soon.
Again, very grateful for your mindshare.
Best regards,
-m
Almost forgot,
I really don't know what you mean by this ... when you get a chance let me know, please. If it's a well known concept I should have read by now, throw me a link if you want. best regards, -hThat would also allow you to flush-mount your speakers, and reap all the major benefits of doing that.
Even more reason why the room should face "down"! The ceiling should be lower over the speakers, rising to maximum height at the back of the room (behind your head).In the provided drawings the "bottom" as you call it is 9 ft high, while the "top" (where I originally put my mix position) is 14 ft high.
STC is just a single-number rating for isolation, and isn't any use for studio design in any case. The method for calculating STC does not take into account the bottom two and a half octaves of the musical spectrum (no bass, drums, low keyboards, low electric guitar, etc.), and neither does it take into account the top two and a half octaves (cymbals, violins, top end of electric guitars, etc.). It only considers the middle part of the spectrum, which is not a lot of use for describing how well a wall isolates music! It's fine if all you want is a rough indication of how well your wall will isolates typical office sounds, such as people talking, phones, photocopiers, HVAC air movement, etc. But useless for studios. Similarly NRC is also not much use, since it too is a single-number rating that only takes into account absorption at four specific frequencies in the mid range, and nothing else. Acousticians don't normally talk about STC and NRC when referring to walls, preferring the terms "Transmission Loss" and "absorption curves". So even if your hypothetical new wall did have exactly the same STC and NRC as the right wall, it could still sound very, very different. And once again, even if you could get them matching perfectly, there is no need to do that, since what you are interested in is mostly the reflections from the wall, not how well it isolates.So if I read you correctly, it doesn't matter what sort of trickery I come up with to get the STC and NRC matching,
Right! :)the ears would "see" different sounds from left to right and so that mix position would be bad for mastering or anything requiring critical listening through balanced monitoring system. That's terrible news.
Take a loo at the book by Cox and D'Antonio on diffuser theory: They figured out the math that describes how diffusers work, and therefore how to design them and build them for specific purposes. They also figured out that all numeric-based diffsuers cause "lobes" in the way the diffsue sound: it is not even in all directions. Some directions get more intensity, others get more phase shift/ time delay. There's a certain distance that is needed for those lobes to even out and smooth over. It depends on wavelength: you need to be at least 3 full waves away from the diffuser in order to have reasonably smooth lobes. And that "3 waves" refers to the lowest cut-off frequency. Later they discovered that diffusers can still scatter sound, even though it is not diffused, for a full octave below the cut-off frequency, so they amended the "3-wavelength rule" to a "7 wavelength rule". And added that, regardless of wavelength, you still need to be ten feet away. Which leads one to wonder just how well the designers of some studios understand diffusion, when they put a couch right in front of the back wall Skyline diffusers, just a few inches from the ears of the folks sitting there...Also thanks for your pointers about Diffuser strategies, I didn't know you required a baseline distance but can see how it makes sense.
No they wont, and it doesn't matter much of they are! First, there will be major bass trapping back there in any case. That goes without saying. That will take care of all but the very lowest frequencies, which will be a problem anyway, as that's where the modal issues and SBIR live, Those are very long wavelengths, so no matter what your rear wall shape is, they will still be there. Secondly, any mid-range issues will be well outside the Haas time, and well attenuated, so your brain will be able to deal with them without any problem. It's only early reflections (arriving sooner than the Haas time) that are a problem. The room absolutely must be symmetrical in the front half, but that's nowhere near so critical for the rear half.My main concern with that orientation is that the reflections coming in from the back of my head behind my left and right ears will be so different.
Absolutely. That is, indeed, the way to do it. I normally use superchunks in the corners and thick 703 across the rest of the rear wall, or better still, deep hangers across the entire rear wall. YOu have the space to do some of that, even though it won't be symmetrical.Perhaps heavy handed absorption is needed then, on that new back-wall
You will need at least some treatment there. The general rule is "hard floor, soft ceiling", regardless of height. If not, you won't be able to meet the spec. ITU BS.1116-2 is what you should be aiming for...Another concern was that with the 14 ft high ceiling I had planned on not treating my "roof" at the mix position at all,
Your ceiling is already angled fairly steeply. When you do your ray tracing exercise to figure out reflections, you'll know if that is enough or not. Hanging a cloud at an angle is no big deal: it's no different than hanging it straight, actually!and now at the 9 ft high end, as you mention I probably have to start looking at doing some kind of simple cloud install in there, which at an angle because of the ceiling might become tricky...
Unfortunately not.... that recovered space needs to be used for bass trapping.On the bright side, re-imagining the design to actually use that space which I was willing to let go, I get a feeling that there is space now to make one of those "Vocal walls" (?, don't know how to actually call those micro amphitheater looking, enveloping walls that work great for tracking a singer-songwriter with guitar and mic).
It's a very well known concept! Also known as "soffit mounting". It totally eliminates all of the artifacts associated with the front wall, from having a speaker emitting sound inside the room. No more front wall SBIR, no more edge diffraction, no more power imbalance, no more comb-filtering or other phaseing issues. Just pure clean sound direct from the speakers to your ears. The speakers in this room ar flush mounted: viewtopic.php?f=2&t=20471 --- as are almost all the speakers in the rooms that John designs, and also the ones that I design. As well as the rooms designed by many other people. If you combine that with the principles of RFZ and the specs from BS.1116-2, that's the best way of getting a clean, tight low end, perfect stereo image, a broad, accurate sound stage, wide sweet spot, and totally neutral room acoustics, just like you see in the graphs on that thread. That should be your goal. - Stuart - - Stuart -I really don't know what you mean by this ... when you get a chance let me know, please. If it's a well known concept I should have read by now, throw me a link if you want.That would also allow you to flush-mount your speakers, and reap all the major benefits of doing that.
Ok got the SketchUp finally "done"
I'll share it right away and respond right after.
I also got the Pictures, but I'll need to the phone-to-computer song and dance first, so incoming soon.
3 main quick points, though:
1.
BIG SURPRISE!
all this time I had thought the "low" side of the room was 9 ft high floor to ceiling.
I DON'T KNOW HOW I "LEARNED" THAT MEASUREMENT, BUT IT WAS WRONG.
The "low" side of the room is actually 10' 6" which is not too shabby!
2.
So, there' an irregular single glass window pane at the top of the diagonal wall which I just couldn't adjust to correct shape in SketchUp, please forgive me but I really tried exploding and adjusting and it just kept being disfigured. As is, it conveys the basic idea.
3.
The electrical boxes are the correct height (15") but left to right were eye-balled, if this becomes critical I can update it no problem. It'll just take even more time in SketchUp.
Dang, "the file is too big, maximum allowed size is 500 KiB"
but my .SKU is 7MB so...
Is the "no links allowed" rule still enforced?
Let me know guys,
-h
Ah, well that's heartening. The first sources of my instruction in these matters stressed the importance of #1 reflections from the normal planes out your ears between the monitors and yourself, and #2 the back wall. In any case that was then, this is now!The room absolutely must be symmetrical in the front half, but that's nowhere near so critical for the rear half.
w00t thanks for the reference!If not, you won't be able to meet the spec. ITU BS.1116-2 is what you should be aiming for...
I just discovered that the angle is less severe now that it goes from 10.5 feet to 14 feet, instead of 9 feet to 14 feet. But still it's as you say, we'll need to check regardless. And the installation is what it is, not impossible at all. The part I wish to ask about is what you mention about the Ray Tracing exercise. I've seen the sketches for some studio designs and could emulate that, but I wish there was a guide or reference doc to really nail the exercise on the head. Also if there is some sort of tool or plugin to make the process less manual!Your ceiling is already angled fairly steeply. When you do your ray tracing exercise to figure out reflections, you'll know if that is enough or not. Hanging a cloud at an angle is no big deal: it's no different than hanging it straight, actually!
** Sad Trombones **Unfortunately not.... that recovered space needs to be used for bass trapping.On the bright side, re-imagining the design to actually use that space which I was willing to let go, I get a feeling that there is space now to make one of those "Vocal walls" (?, don't know how to actually call those micro amphitheater looking, enveloping walls that work great for tracking a singer-songwriter with guitar and mic).
Ah, so it’s what I know as “soffit” installation. Well a real knowledgable, old wise guy from the music industry I’m almost friend with online, once told us young ones learning from him how Soffit installs are really difficult to “get right” and super easy to “get wrong”, and so for most project studios the proposition is most of the time not worth the effort. This was some time ago, so maybe there’s been some improvement on shared designs and that kind of thing, but I guess this was in the back of my mind and why the modest studio builds and designs I’ve participated in have not included Soffit installations. I'll try to find that conversation and get back to you. I have two good monitor stands, but I agree if Soffit was achievable then it'd be superior! Thanks for all your help, if there is a way to share the SketchUp .SKP file let me know best regards, -mAlso known as "soffit mounting".
Upload your file to a file sharing service such as Dropbox, then post the link here. - Stuart -Dang, "the file is too big, maximum allowed size is 500 KiB"
That's actually correct... sport of! The early reflections are, indeed, the biggest problem in many rooms, but they can come from ANY surface in the room that is between you and the speakers, if it happens to be in the right location and at the right angle. That's why most modern design concepts use the "Reflection Free Zone" concept, in one of its many incarnations, to eliminate this. With this concept, surfaces at the front of the room are carefully angled such that NO early reflections get to your ears. All of those are sent to the back of the room, bypassing your head, hence the name: this design concept creates a "zone" around your head that is "free" from all early "reflections". RFZ. With that done, the most important surface in the room then becomes the rear wall, but not because of early reflections! By definition, any reflections coming back to your head from off the rear wall are "late", not "early". They are outside the Haas time (assuming the room is large enough), and therefore not such a problem for your brain to deal with. The biggest problems with the rear wall are SBIR, modal response, and bass build up. The sound energy that arrived there after being deflected around your head by the RFZ-style front end, can mostly be absorbed or diffused (if the room is large enough), since it is mostly mids and highs, but the other issues (SBIR, modes, bass) are all low frequency problems, and need a bit more attention. So your original instruction was sort of correct, but not for the right reasons in modern studios... :)The first sources of my instruction in these matters stressed the importance of #1 reflections from the normal planes out your ears between the monitors and yourself, and #2 the back wall. In any case that was then, this is now!
Unfortunately, not. It's a slow, boring, painful, repetitive process: After you do it a few dozen times for a few dozen studios, you start to get a feeling for what will work and which ray will go where, so it's possible to simplify and use fewer rays, but it's still slow, boring...Also if there is some sort of tool or plugin to make the process less manual!
I would certainly agree with your friend that soffits are difficult to get right, but I would not agree with him that it's not worth the effort! :) It is worth it. In my opinion, it's the single most important thing you can do to your entire room, to tame the acoustics. It eliminates all of the artifacts associated with having the speaker inside the room, because in effect it totally removes the speaker from the room! The speaker becomes one with the front wall, so in effect, it is no longer in the room, and cannot affect the room the way it would if it were in it. Yes, your friend was right that it is not so easy to do it correctly, but if you look around the forum you'll see a LOT of project studio builds where it has been done, very successfully. What matters is being guided correctly while doing it, so you are not doing it alone! That's what the forum is for. I'd also disagree with him that it's not worth the effort for project studios: On the contrary, that's where it gives the most benefit, and is most worth the effort! In a nice large studio, soffit mounting is not needed so much, but can still produce useful benefits. But in a small studio, that's where it is needed most. The smaller the studio is, the more it needs flush mounting. Take a look around John's studio build section and notice just how many of his studios are done with soffit-mounting. Virtually all of them. Take a look around industry magazines, and notice that a lot of studios are done with soffit mounting. The larger ones less so, but the small ones very frequently are. IMHO, it is well worth doing. - Stuart -Well a real knowledgable, old wise guy from the music industry I’m almost friend with online, once told us young ones learning from him how Soffit installs are really difficult to “get right” and super easy to “get wrong”, and so for most project studios the proposition is most of the time not worth the effort.
Ah great,
here's the link to the SketchUp file of my pentagonal room with inclined ceiling.
Mesmer Room 2017 6.6MB
best regards,
-h
Great valuable info all around,
thank you so much. Great points about RFZ, ray trace exercise and Soffits.
I see now as you told me in your first response, it was always better to imagine the studio this way around "expanding" towards the back.
I wish I could buy you a good Mendoza wine.
I'm convinced I'll go for Soffits now,
my last concern is my Active monitors...
since they're active it means each one has it's own power amp and electronics inside their own cabinet... wouldn't enclosing them in their own soffit chamber cause overheating issues? I haven't looked at any design schemes for soffits that may be being passed around the web so maybe the design already has some sort of heat-management or venting in it ... I just wonder if I'd be asking for trouble in the temperature department.
cheers,
-m
That's actually correct... sport of! The early reflections are, indeed, the biggest problem in many rooms, but they can come from ANY surface in the room that is between you and the speakers, if it happens to be in the right location and at the right angle. That's why most modern design concepts use the "Reflection Free Zone" concept, in one of its many incarnations, to eliminate this. With this concept, surfaces at the front of the room are carefully angled such that NO early reflections get to your ears. All of those are sent to the back of the room, bypassing your head, hence the name: this design concept creates a "zone" around your head that is "free" from all early "reflections". RFZ. With that done, the most important surface in the room then becomes the rear wall, but not because of early reflections! By definition, any reflections coming back to your head from off the rear wall are "late", not "early". They are outside the Haas time (assuming the room is large enough), and therefore not such a problem for your brain to deal with. The biggest problems with the rear wall are SBIR, modal response, and bass build up. The sound energy that arrived there after being deflected around your head by the RFZ-style front end, can mostly be absorbed or diffused (if the room is large enough), since it is mostly mids and highs, but the other issues (SBIR, modes, bass) are all low frequency problems, and need a bit more attention. So your original instruction was sort of correct, but not for the right reasons in modern studios... :)The first sources of my instruction in these matters stressed the importance of #1 reflections from the normal planes out your ears between the monitors and yourself, and #2 the back wall. In any case that was then, this is now!Unfortunately, not. It's a slow, boring, painful, repetitive process: After you do it a few dozen times for a few dozen studios, you start to get a feeling for what will work and which ray will go where, so it's possible to simplify and use fewer rays, but it's still slow, boring...Also if there is some sort of tool or plugin to make the process less manual!I would certainly agree with your friend that soffits are difficult to get right, but I would not agree with him that it's not worth the effort! :) It is worth it. In my opinion, it's the single most important thing you can do to your entire room, to tame the acoustics. It eliminates all of the artifacts associated with having the speaker inside the room, because in effect it totally removes the speaker from the room! The speaker becomes one with the front wall, so in effect, it is no longer in the room, and cannot affect the room the way it would if it were in it. Yes, your friend was right that it is not so easy to do it correctly, but if you look around the forum you'll see a LOT of project studio builds where it has been done, very successfully. What matters is being guided correctly while doing it, so you are not doing it alone! That's what the forum is for. I'd also disagree with him that it's not worth the effort for project studios: On the contrary, that's where it gives the most benefit, and is most worth the effort! In a nice large studio, soffit mounting is not needed so much, but can still produce useful benefits. But in a small studio, that's where it is needed most. The smaller the studio is, the more it needs flush mounting. Take a look around John's studio build section and notice just how many of his studios are done with soffit-mounting. Virtually all of them. Take a look around industry magazines, and notice that a lot of studios are done with soffit mounting. The larger ones less so, but the small ones very frequently are. IMHO, it is well worth doing. - Stuart -Well a real knowledgable, old wise guy from the music industry I’m almost friend with online, once told us young ones learning from him how Soffit installs are really difficult to “get right” and super easy to “get wrong”, and so for most project studios the proposition is most of the time not worth the effort.
Vents are always needed in soffits, even for passive monitors. The speakers are surrounded by huge volumes of insulation, so if there were no vents, they would get very hot, quickly. There is always an air path up past the back of the speaker to provide cooling airflow. It is a broad, wide path, and draws in cool air from below, up through the shelf system that the speaker sits on, then up through the insulation (you make a wire cage out of chicken wire or something similar, to hold the insulation out of that path), then out through either the top of the soffit, or the front of the soffit, through a wide slot. You can sometimes see those slots in photos of control rooms, but in other cases they are hidden. But they are still there! Normally, air flows through that "chimney" just by convection, but for very large speakers, or speakers that are run at very high levels all the time, it might be necessary to have a small, very quiet fan to help move the air. Take a look at the soffits in this room: viewtopic.php?f=2&t=20471 Those are Eve Audio SC-407's. 600 watts each. Imagine how hot those would get if there were no cooling. But there is: as I described above, there's a path up behind each speaker, and it exits the soffit above the cloud, out of sight. The air coming out of the slot is only slightly warm, even when the speakers are run at high power for a long time. And that's considering that those speakers are not designed to be soffit mounted, as they are rear ported, but we plugged the ports in order to mount them. They are also designed to be used horizontally, but we used them vertically here. And all of that was done with the blessing of the chief engineer at Eve-Audio. I checked with him for his recommendations for that, and he gave me the OK to do it that way. And those speakers work just fine, no overheating at all. Not even close. (Great guys at Eve, by the way. Very helpful.). As long as the air path is built properly, there will be plenty of cooling flow. - Stuart -since they're active it means each one has it's own power amp and electronics inside their own cabinet... wouldn't enclosing them in their own soffit chamber cause overheating issues?
Great!
I look forward to the challenge!
That Missouri studio looks amazing, was ogling at all that on the Construction thread #wow, bravo sir.
That lead down a rabbit hole regarding enveloping the fiberglass in thin plastic and looking at the health studies available
hours fly by.
best regards,
-h
... And here's the link to the same model, cleaned up, organized in layers, and with the speakers and mix position geometry situated correctly for that room ... :) http://spartanew.digistar.cl/SayersForu ... 3d-S05.skp - Stuart -Ah great, here's the link to the SketchUp file of my pentagonal room with inclined ceiling. Mesmer Room 2017 6.6MB best regards, -h
You are such a treasure to these forums. Thanks so much, will be taking a look right now! minor update: I just ordered "Graphic Guide to Framing" and "The Very Efficient Carpenter" and a third one about Windows and doors. With those books and your collective guidance hopefully in a month's time or less I can start rolling up my sleeves and making the ultimate investment in this other half of my trade. best regards, -m... And here's the link to the same model, cleaned up, organized in layers, and with the speakers and mix position geometry situated correctly for that room ... :) http://spartanew.digistar.cl/SayersForu ... 3d-S05.skp - Stuart -Ah great, here's the link to the SketchUp file of my pentagonal room with inclined ceiling. Mesmer Room 2017 6.6MB best regards, -h
Do you also have "Master Handbook of Acoustics" by F. Alton Everest, and "Home Recording Studio: Build it Like the Pros", by Rod Gervais? If not, then get those too. Those are arguably the two best books available for home studio builders. - Stuart -I just ordered ... With those books and your collective guidance
Greatness, I'll have to pick them up too! So my head is still spinning from chasing down infinite details across so many threads and links. It'd be boring if I listed all the topics here, so I'll focus on the three giving me the most body-CPU over-heat issues: ONE So, I would summarize the Soffit collective knowledge about building approaches to them along 3 main lines:Do you also have "Master Handbook of Acoustics" by F. Alton Everest, and "Home Recording Studio: Build it Like the Pros", by Rod Gervais? If not, then get those too. Those are arguably the two best books available for home studio builders. - Stuart -I just ordered ... With those books and your collective guidance
- Build an extremely sturdy, solid inner wall with a shelf or drawer in it, your speakers will be fixed in/on-top-of this. Then Build your outer wall leave. Sheet that outer wall, leave a reasonably wide (there are formulas) empty space were your "bevel" made of really solid dense material will frame your actual speaker. The bevel is just tall and wide enough for your specific speaker. Gaps between speaker and bevel should be no bigger than 5mm.
- Build a Box out of solid dense material, use resilent channel and/or isolation clips and/or all other tricky joinery gadgets to decouple that box (where your speaker will be) from your front wall.
- Using monitor stands inside the front wall, and making the solid box out of poured concrete inside the front wall were mentioned ... but let's leave that for the *really* nutty people. Not use we're *completely* sane. yes sir.
Hey guys,
here's the Pics as requested. I've read 2 of the 3 books on carpentry I received, plus John's book cover to cover as well. I was heartbroken to read in the manual for my DSM-2 monitors that they shouldn't be Soffit installed and it's highly not recommended. I had already started to design the framing for that front wall as the sketchup I'll be uploading in the next post shows, but have to leave that aside as after considering the renovation budget I couldn't justify a Monitor upgrade at this time.
I'll have to live with that, as John says in the book. For the time being at least.
Projectwise I am still in the Design stage, although hopefully moving on to getting the hands dirty soon.
Again, as John says in the book, although I am highly eager to start building a small delay now in order to get things right is a really good investment with the best payoff. So I've just been programming a ray tracer for personal use. So the focus at the moment is 4 things:
1. waiting on some Green Glue (more on that next post)
2. getting the diagonal back wall big single pane window replaced with newer model and laminated glass (current one broken and inaccessible).
3. waiting on cheapo $50 usb calibration mike suggested right there in the REW software page to arrive (haven't got a useable OMNI in my mike closet)
4. developing an un-ambitious ray tracer for personal use (just keeps the mind busy and the emotions at bay).
all comments welcome
best regard
-M
Here's a Link to the latest Sketchup of the room!
https://dl.dropboxusercontent.com/u/1485047/mesmer_room_3d_treatment_bottom9.skp
I tried to put as much information as possible in it, so many "improvements" proposed!
So guys, after all your feedback, comments and or inputs, if the design is the best possible scenario within what's reachable now ... I'm ready to begin building it. I think i'd do it in two stages:
Stage 1: take care of the back-wall. This means:
- Demo out those miami glass windows (3 x 24") and close up that big 72" x 58" (1.82 m x 1.47 m) with triple layer of the heaviest Gypsum Board availalbe (bonded with Green Glue compound so as to make it single leaf). I'd nail it straight into the cinder blocks above and below, correct? ( I would love some confirmation on the correct install procedure here).
- Reduce the visible area of the single glass pane in the corner, closing the hole up the same way as above but with single layer of heavy Gypsum Board. The objective is to get 2' x '2' solid corner in which to eventually put a Superchunk or regular Bass Trap as in the book.
- Getting the diagonal window replaced (it's broken now, and the ironworks on the inside of it make it so that changing the glass is impossible).
- Swapping the current Entry Door With Sidelight assembly for a really narrow 30" door, and shifting it "back" so that the resulting corner can be filled with cinderblocks and regular finished masonry. From the mix position this is the Front Right corner.
- Domolition of the cornermost miami glass window panel on the opposite corner, and filling the whole up with cinderblocks and regular finished masonry. From the mix position this is the Front Left corner.
You do not need to upgrade your monitors: those are fine, and they CAN be soffit mounted!!!! Did you read what the manual actually says? Here is the text:I was heartbroken to read in the manual for my DSM-2 monitors that they shouldn't be Soffit installed and it's highly not recommended. I had already started to design the framing for that front wall as the sketchup I'll be uploading in the next post shows, but have to leave that aside as after considering the renovation budget I couldn't justify a Monitor upgrade at this time.
Let me repeat that with the relevant part highlighted:Do not soffit mount or otherwise install the speakers in an enclosed space. The speakers require free air flow around the back panel.
Read it carefully: It does not say that you cannot soffit mount your speakers. It says you cannot soffit mount them in an enclosed space! That's a very different thing. They can be soffit mounted, as long as there is sufficient air flow around the rear panel. That's the only restriction. A badly designed soffit that puts them in an enclosed space would not provide airflow. A correctly designed soffit will ALWAYS provide sufficient airflow to keep them cool. Take a look at this thread: viewtopic.php?f=2&t=20471 The speakers in those soffits are also not designed to be soffit mounted. The manual says the same thing. When I designed the soffits for those, I contacted the chief engineer at the factory, explained how I was doing it, and he agreed that there was no problem doing it that way. He even gave me some tips on how to do it better for that specific model. Those speakers are rated at 800 Watts each, meaning that they are producing about the same amount of heat as a small single-bar room heater! Yet there they are, running just fine. Because there is sufficient air flow around the rear panel. And look at the results... So as long as your soffit is correctly designed, does not fully enclose them with no venting, and provides enough air flow, then they CAN be soffit mounted. Pretty much any speaker can be soffit mounted. - Stuart -Do not soffit mount or otherwise install the speakers in an enclosed space. The speakers require free air flow around the back panel.
Well ok, cool I want it to be possible,
my sketchup has the bottom plates for a front wall and the soffit "shelf" strategy in place I think I could manage building them no problem, my concerns were:
- Since they WILL end up surrounded with insulation, aside from that back channel column allowing the vertical movement of hot air, it seems like the heat would keep building up inside that semi enclosed box and eventually cook them (even if the back of the unit has fresh air flowing and is kept at good temp). Can I build an oversize box inside that front wall, and have the bevel be tight against the front face of the speakers like regular soffit recommendations? does it still behave like a normal soffit installation? I'm thinking 2x or 3x the size of the speaker...
- The switch to turn them on and off is on the back of the unit. So I'd have to look into making some sort of jig-stick or something to poke into "some hole" (probably not the very slim opening between the the front of the speaker and the bevel (5mm iirc) ... or maybe some RC servo motor finger??? ... or maybe live with switching them on and off from an interrupter in their mains AC power supply (feels like it could damage them??) [*} Finally I examined them more closely and remembered that they are Ported (pretty big hole) in the back... It feels like that Port is part of their tuning and sticking the speakers inside soffit box would throw off their phase alignment or other important params. Alternatively one could say I could try plugging the Port, but what effect would that have on their sound?! If I had a line with the speaker designer/engineer like you did it would be great to consult on that one. As it is, I'd feel safer just playing it safe. [/list]
The way I do it, there's about an inch of airflow space all around the bottom and sides of the speaker cabinet itself, plus about 3 inches behind the rear panel, fed by a huge hole up through the shelf. There's no shortage of airflow. I create a "suspension" system that "floats" the speaker inside the enclosure box using Sorbothane rubber pads for separation. I carefully calculate the tensions, pressures and deflections in the Sorbothane to ensure that the speaker floats down to very low frequencies, well below the cut-off (or cross-over, if I'm using a sub as well). So there's plenty of space for air movement all around the cabinet.... Like I said: "When done correctly...." :)Since they WILL end up surrounded with insulation, aside from that back channel column allowing the vertical movement of hot air, it seems like the heat would keep building up inside that semi enclosed box and eventually cook them (even if the back of the unit has fresh air flowing and is kept at good temp). Can I build an oversize box inside that front wall, and have the bevel be tight against the front face of the speakers like regular soffit recommendations? does it still behave like a normal soffit installation? I'm thinking 2x or 3x the size of the speaker...
There's no need to invent any fancy way of turning them on and off. Just have an external switch for that, probably on your desk, along with all your other gear. Use something like a Furman power controller for that: Turn everything on and off from one point. Or just hard-wire them into the distribution panel, on their own breaker.The switch to turn them on and off is on the back of the unit. So I'd have to look into making some sort of jig-stick or something to poke into "some hole" (probably not the very slim opening between the the front of the speaker and the bevel (5mm iirc) ... or maybe some RC servo motor finger??? ... or maybe live with switching them on and off from an interrupter in their mains AC power supply (feels like it could damage them??)
Take a look at the thread I linked you to above, for Studio Three (previously called "Monstertrax"). Those are Eve Audio SC-408 speakers in there: they are rear ported, just like yours. And they are soffit mounted! And look at the acoustic response graphs for that room... It would be very, very hard to get better response than that! :) The bass reflex port on a speaker is NOT part of the tuning of the speaker: It's actually part of the "de-tuning" :) The only purpose of a bass reflex port is to extend the lower end of the frequency response, such that the speaker seems to be able to produce frequencies lower than it actually can. It works because it is a tuned port: It is basically a Helmholtz resonator, in reverse. It resonates at a certain frequency, which was set by the designer. So for example, of the speaker by itself without the part was able to get down to 40 Hz (hypothetically), then the designer might choose to set the resonant frequency to the bass reflex port to 34 Hz (hypothetically), thus apparently "extending" the response by a couple of notes. The reason it works is because even though the "cut-off" for the speaker by itself was 40 Hz, it is still putting out substantial energy below that (the frequency response curve "rolls off" slowly), so there is plenty of energy to trigger the resonance at 34 Hz. And when that happens, the resonance "appears" to add even more energy, thus seeming to push up the volume at that frequency: it makes the tones below 40 Hz seem louder, and thus the speaker seems to have a better frequency response than it really does. But it's all fake! I mean, it works, but at a cost! Since that is a RESONANT device, it takes a short amount of time for the resonance to be established, and it continues for a short extra time after the driver stopped producing that note. So in reality, it "smears" the note over time: It sounds louder, yes, but it loses "tightness" because there's a delay while the resonance builds, and another delay while it dies away again. The times are very short, yes, but still long enough to make a difference. That's why reflex speakers never seem to sound as "tight" in the low end as sealed speakers. In fact, many engineers complain that they can hear the resonance itself happening, and there's even a semi-technically term for that: "chuffing". It can also produce what many people call "one note bass", where all the bass notes seem to play at the exact same frequency; so as your bass player runs up or down the scale, it all sounds like one single note, repeated. And it can also sound "boomy". So what happens if you damp that port? What happens if you put some insulation in the end of it, such that the resonance is killed? Well, what happens is nothing! :) The resonance does not happen, there is no "smearing" of the bass, and the frequency response returns to roughly what it would have been if the bass port was not there at all. So you lose a bit of intensity in the low end... but that's no big deal at all if you soffit mount your speakers! One of the major benefits of soffit mounting is that it restores the power imbalance, increasing the entire low-end response by 6 db! And it does so naturally, without any resonance, smearing, or "chuffing" or "booming". The reason for this is also interesting:... For any object, tones where the wavelength is significantly smaller than the object will get reflected off it, and notes where the wavelength is significantly larger than the object will be partly reflected and partly wrap around it: For a speaker, that means that notes where the wavelength is smaller than the dimensions of the box will only go forwards, into the room, and notes where the wavelength is larger than the dimensions of the box will go out on all sides. So high frequencies will be focused in one direction, like a spotlight shining at you, and lows will go out in all directions, like a balloon expanding around the speaker. But what does that mean in terms of power? It means that ALL of the power put out by the speaker in highs goes towards your head, but only HALF of the power in the lows goes to your head: the other half goes behind the speaker: it wraps around "backwards". So there is an inherent "power imbalance" between highs and lows. Only half the lows get to you. In decibels, that means that you get 6 dB less in the lows than in the highs (half the power). The point where things change over from "spotlight beam" to "expanding balloon" is governed by only one thing: the smallest dimension of the front panel of the speaker, which is technically referred to as the "baffle". The wavelength that corresponds to the width of the baffle is the mid point: all shorter waves shine forwards, and all longer waves wrap around backwards. So, since there is a jump in the frequency response curve at that point, this whole effect is called the "baffle step response", because it looks like a "step" in the frequency response. Actually, it's not really a "step": just a change in the curve. To compensate for the "baffle step response" problem, all speaker manufacturers put twice as much power into the lows as the highs, and they have a cross.over circuit that carefully applies just the right amount of power to each driver, following the exact opposite curve of the "baffle step response" curve. But soffit mounting does that for you! It solves the power imbalance problem naturally! It removes the baffle step completely, since the front panel of your soffit acts like a giant baffle that is bigger than all the wavelengths. Technically, it is called an "infinite baffle". And since it solves the problem naturally, there are no drawbacks, only benefits. And since you no longer need the complicated circuitry and double-extra power inside your speaker, you can turn that off. That's why most good speakers have a control on the back, called something like "room correction" or "bass roll-off" or "bass tilt" or something like that. It allows you to remove the correction that the manufacturer had to put inside, since you don't need it any more. It also means that the speaker runs cooler, since it does not need to put out twice as much power in the low end.... :) As I mentioned, the Eve SC-407s in that thread I linked you to are not rear-ported, and are not even supposed to be used that way, in soffits. But I spoke to the chief designer at Eve Audio, explained how I intended to do it, and he agreed with me that it would work just fine. He did not object, and even gave me some tips on how to do it more efficiently. A very helpful guy. And fantastic speakers. So that's the looooooong explanation: You can soffit mount rear-ported speakers, if you do it right. You need to allow for sufficient cooling, but since the power amps only need to run at a lower level due to the power imbalance correction, they will be running cooler anyway. And if the bass reflex port is on the back, you need to damp it, in one way or another (not "plug" it! Just damp it). That's the only difference, as compared to other speakers. The only speakers that you cannot soffit mount, are ones that have extra drivers on the sides, top or bottom. I used to think that it was impossible to soffit-mount rear ported speakers. Then later I thought it was just a bad idea and really hard to do. But now I know better: it can be done, and it's not that hard, once you understand the issues. The proof that it works extremely well is right there in that thread: Look at the acoustic response graphs, and you'll see how well it works! If you can find a room that has better, flatter, cleaner response than that, then I'd love to see it! And yet those speakers are rear-ported, and meant to be mounted horizontally, not vertically... :)Finally I examined them more closely and remembered that they are Ported (pretty big hole) in the back... It feels like that Port is part of their tuning and sticking the speakers inside soffit box would throw off their phase alignment or other important params. Alternatively one could say I could try plugging the Port, but what effect would that have on their sound?!
I'm here! John is here! Glenn is here! Andre is here! Others are here! :)If I had a line with the speaker designer/engineer like you did it would be great to consult on that one.
Nope! The bass traps above an below the speaker section are NOT outside the room! The SPEAKER is outside the room, but the bass traps are not. The center section, where the speakers are mounted, constitutes the infinite baffle that puts the speaker outside the room, but the rest is still inside. There's a very large air gap down next to the floor, normally 12" or so high and the full width of the soffit, which exposes the hangers to the room. That's also where the cooling airflow comes from, under the speaker. And there's another large space above the speaker, which can be used for additional bass trapping.If the frontwall(+soffit installed speakers) is built, I think the corner bass traps on the front become irrelevant (they're outside the room, technically).
It's a small room: it will need LOTS of bass trapping. As much as you can fit inside, in fact. The smaller the room, the more bass trapping you need. It is impossible to put "too much" bass trapping in a room. In Studio Three (which is a fairly large room) there's a huge amount of bass trapping above the soffits, an along the side walls (wall/ceiling corner), and in the vertical corners, and on the rear wall, and under the raised platform where the client couch is.... And even then, it's not enough. I would have liked to put more in, but there's no more space!Then the room has only one bass trap, so ... maybe make up a horizontal superchunk to reside on top of the front wall, between a horizontal plane and the inclined roof
:shock: Nope! despite the name, "Green Glue" is not glue. It is not adhesive. You cannot use it to stick things together. That is NOT what it is for! It is an acoustic damping compound. Technically, it is a visco-elastic polymer that acts as a constrained layer damping material between two layers of drywall (or plywood, OSB, MDF, etc). But it is not glue.Is attaching 3x 5/8" Gypsum boards green glued together
Why do you want to put drywall on your cement walls? For what purpose?directly into the cement above and below with long cement screws
The cement is not a solid surface? What is that wall surface like now? If it is cement, then that's all you need. Paint it with masonry sealer ("sellante de cal") to seal the porous surface, and you are done. The rear wall of your room will never be seen again: You will have very large superchunks in the corners, floor to ceiling, and the rest of the wall will be covered with 6" of fiberglass or mineral wool insulation: It does not matter what the wall looks like behind that... :) - Stuart -I'm just trying to create solid surfaces for the Absorber treatments.
Great!
thank you Stewart for putting so much passion and energy into your responses.
Regarding the flush mounting soffit assembly, I was threading along very old memories from my DSP class some 10 years ago. My very hazy memory spoke to me about the speaker cabinet design, I seemed to remember that whole "radiators push out the same wave going out to the front, inverted in phase towards the back" and long story short those contrarian waves bounce around inside the speakers. When they are ported, as you explained in the form of resonators, then that was a consideration in the design of that bouncing around. Such that plugging it (which you very clearly explained is not the right approach, more like dampen it so that the resonance can't trigger) messes with the intended designed bouncing around inside the cabinet. I'm just trying to explain to you where my hesitation was coming from.
Anyway this is a moot point, since, you have very professionally dismantled all those points, so I am now building them and no one's gonna stop me!
There are two things I think got lost in the translation, and I'd like to clarify.
1. About the bass traps in the front of the room. The space I was thinking about is the front left and front right corners. As I proposed they'd be made 2 feet in length, cinder blocks each side of the triangle. Then I'd fill them with UltraTouch or Roxul or the best available fiberglass either in superchunk fashion or like the ones in the book. What I was now trying to work through was this: Those corners would now be behind the Gypsum/Sheetrock of the front wall, behind the frame for the whole thing including the Flush mounting soffits. So I was thinking, since the resulting room corners are now the ones between the new Gypsum/Sheetrock and the door on the right and the Gypsum/Sheetrock and the windows on the left, then does it still make sense to fill the original corners with insulation, if they are no longer in the room?
2. About the back wall.
It's not like that! I'm speaking about the situation arising from removing the windows in the back wall. If I take the big hammer and demolish those windows, I'm left with a big square hole. The pics that show this are titled "windows_to_be_replaced_with_gypsum.jpg" and "back_wall_window_window_corner.jpg". What I am saying is that, as best as I can tell, the best approach after removing the windows is to take a couple of 4x8 panels and attach them to the remaining wall. This happens to be the 3' of cinderblock/cement below the hole and 2' above the hole. So as it currently stands, I'd take the correct screws (don't know which ones yet) and screw the Gypsum or Sheetrock panels directly to the available surface (above and below). The Green Glue compound in this case is just a minor provision to try to improve the isolation provided by the triple gypsum stack. Seen from the outside in, that same wall is one of the two walls forming the corridor entrance to the Whole House ... this is why aesthetics come into play and why the plants are there. So my original question was along the lines of, for the purpose of attaching the 4x8 and forming that solid back wall, is screwing into cinderblock the best approach? or maybe better with high powered nails? or maybe just Liquid Nails and be done with it? Hey man, thanks for all your support regardless. Please don't misinterpret the wordiness for bad attitudes; ya know all these things are prone to have so many little details that just throws most everybody off in wrong semantics or directions. :D Again, thanks and hopefully some action shots soon! -M:shock: Nope! despite the name, "Green Glue" is not glue. It is not adhesive. You cannot use it to stick things together. That is NOT what it is for! It is an acoustic damping compound. Technically, it is a visco-elastic polymer that acts as a constrained layer damping material between two layers of drywall (or plywood, OSB, MDF, etc). But it is not glue.Is attaching 3x 5/8" Gypsum boards green glued togetherWhy do you want to put drywall on your cement walls? For what purpose?directly into the cement above and below with long cement screwsThe cement is not a solid surface? What is that wall surface like now? If it is cement, then that's all you need. Paint it with masonry sealer ("sellante de cal") to seal the porous surface, and you are done. The rear wall of your room will never be seen again: You will have very large superchunks in the corners, floor to ceiling, and the rest of the wall will be covered with 6" of fiberglass or mineral wool insulation: It does not matter what the wall looks like behind that... :)I'm just trying to create solid surfaces for the Absorber treatments.
Hey Soundman2020 that's really interresting! Could you please explain how do you calculate that?I create a "suspension" system that "floats" the speaker inside the enclosure box using Sorbothane rubber pads for separation. I carefully calculate the tensions, pressures and deflections in the Sorbothane to ensure that the speaker floats down to very low frequencies, well below the cut-off (or cross-over, if I'm using a sub as well). So there's plenty of space for air movement all around the cabinet....