hey i basically copy and pasted this from another forum i posted at but was hoping to deal with more specialized people here for this so here goes
(i hope this is the right forum)
i am a bit in a confused state.. this is the situation:
1) i have a 12.5 x 15.5 ft mixing room with 11 ft ceilings.
2) it currently has 4 ceiling clouds @ 12 degree angles. each is 2ftx8ft and 1inch thick 703 with guileford of maine fabric.
3) all the corners (vertical and ceiling horizontal) are trapped with 6inch 703 2ftx4ft panels with a 4inch thick smaller nested panel behind it.
4) there used to be a skylight about 4x4 and 4 foot deep cavity. it was completely stuffed with insulation (fiberglass, alternating roxul and some other fiberglass panel boards hung with air spaced between) so it's a big bass trap on the ceiling.
5) the entire rear wall has spaced out RPG qrd diffusors
i am in the process of treating the side walls and the front wall. the builder i am working with insists on placing 6-8ft tall x 2ft wide panels to cover most of the front wall and 5 on each side.
i'm fine with the layout however my only concern is he insists on usign a 1inch combination of 2/3 703 and 1/3 705..
i voiced my concern that the 1 inch might be too thin but he insists that they will be fine and with all the trapping i have 2 or 4 inch will be too much and the 1 inch will get the job done fine. he also says that since the framing is 2 inch thick there is approx 1 inch space between wall and the 1 inch fiberglass and that is better than having the panels flush on the wall.
so for wall panels (front and side walls) NOT bass traps in corners, any one care to chime in on the 1inch vs 2/4 inch debate?
tickness of wall panels
Originally posted at johnlsayers.com, topic 18248.
Hi "aramism". Please read the forum rules for posting (click here). You seem to be missing a couple of things! :)
But to answer your question: It depends on what the purpose of those panels is, and what the basic design philosophy of the room is.
However, before getting into that, you have a much more serious problem: Your room is square! :shock: Since both the length and width are 12.5 feet, all modes in the 0,x,0 direction will line up perfectly with all modes in the x,0,0 direction, meaning that you will have huge modal response issues at all frequencies where the wavelength coincide with the room dimensions. For 12.5 feet, that means major modal issues at 45 Hz, 90 Hz. 135 Hz, 180 Hz, etc., all the way up the scale, and those are just the axial modes. The same thing happens with the tangential modes at 68 Hz, 136 Hz, 204 Hz, etc. And since the axials line up almost perfectly with the tangentials at 135 Hz, that is going to be a major problem.
There's a type of graph called a "Bonello Plot" that shows how good or bad a room's modal distribution is. Here is the one for a room with your dimensions:
As you can see, a good room shows a smooth curve. A bad room shows a dip in the curve. A really bad room has two or more dips in the curve. Yours has two.
So before going any further with treatment, I'd strongly, strongly suggest that you back up a few steps and change the basic room dimensions to make it usable for mixing. As it is, there's no way you'll be able to get usable low-end acoustic response in that room. You need to change one of the dimensions to make that space usable as a mixing room. This cannot be fixed by any amount of treatment inside the room: it is an artifact of the room dimensions themselves. Since your contractor seems to know a bit about acoustics, it is surprising that he didn't spot this: it is a major flaw in the room design.
But anyway, after you fix that, there is the issue of how to treat the room. A room with those dimensions needs a total of 428 sabins of absorption to bring it within ITU and EBU specs for a control room. That implies 428 square feet of perfect absorption. As near as I can tell from what you say, your treatment is as follows:
Corners: 2x4 = 8 ft2, x 4 corners = 32 ft2
Clouds: 2x8 = 16 ft2, x 2 clouds = 32 ft2
Skylight: 4x4 = 16ft2, x 1 skylight = 16 ft2
Side walls: 8x2 = 16ft2, x 10 panels = 160 ft2
Total: 240 ft2
So even with all you are doing, you still only have half of the absorption that you need for that room. Nowhere near enough, especially considering the major modal issue you will have (those corner traps are much too small to do much for that).
So your builder is just plain wrong on this: you need much MORE absorption in that room, not less! The equations do not lie.
Not only that, but the Sabine equations assume "perfect" absorption, but there is no such thing in real life: OC-700 series absorption is good stuff, but far from perfect. Take a look at the published specs:
As you can see, even the veritable Holy Grail of 4" OC-703 is far short of being a perfect absorber across the entire spectrum. It is really good, yes, but not perfect. so you actually need MORE surface area of absorption than the equations say.
You also need to balance it across the spectrum. Since the panels do not absorb the same for all frequencies, and since ITU specs don't call for that anyway, you need to place the right amount of absorption for each frequency band. Lows need a huge amount of absorption, mids a lot, and highs much less. So you need to balance that, by properly installing the correct type of absorption at the correct locations in the room, and suitably covering bass traps with limp membranes to reflect highs while absorbing lows.
Now, since your room is small, and since it has major bass resonance issues, let's consider that while looking at what your contractor is proposing: He says you should use 1" 703 or 1" of 705. Look at the specs for that. 1" 703 has an absorption coefficient of .17 at 125 Hz. 1" of 705 has an absorption coefficient of just .02 at 125 Hz.! In other words, they would do practically nothing for you major bass issues. He also suggests using a 1" air gap, but that changes hardly anything at all. It is basically the "A" mounting method shown in the chart above. To get any real benefit from an air gap, it needs to be big enough to have an effect on the wavelength in question. The "E-405" mounting method show in that table does make a big difference, since that is a 16" air gap (405 mm). A 1" air gap will have some effect, but very little.
In any event, as you can see from the chart, 705 is not much use for bass trapping, with or without an air gap, and bass is where your issues are, undoubtedly. 1" of 703 flat against the wall still beats 1" of 705 mounted the same way, across the entire spectrum! 705 is fine for highs, but not for lows. It is simply too dense to be any use for low frequency absorption. Even 701 beats 705!
Sorry, but those are totally uncalled for, and make no sense is such a small room. Numeric sequence diffusers can only be used in rooms that are large enough for the lobing artifacts to smooth out, and yours is nowhere near large enough. Of course, diffuser manufacturers don't bother to tell you about that, but if you check their very own technical data, you'll find out that you need to have AT LEAST 10 feet between a diffuser and the ears of anyone who is doing critical listening. And the distance could be greater than ten feet, depending on what frequencies the diffuser is tuned to. So forget those diffusers: they are doing more harm than good, and they are taking up the space where you need major absorption. You could easily get another hundred square feet of absorption on that rear wall, right where it is needed, and it can be thick, deep absorption, spaced away from the wall.5) the entire rear wall has spaced out RPG qrd diffusors
The part of the front wall that should be treated is the part between the speakers and the wall. That needs to be deep absorption. 4" of 703 is the normal recommendation there. And for the side walls, treatment is needed at the first reflection points, an once again that should be thick, and deep: 4" of 703 (or even 6") over a 4" air gap is a good place to start.i am in the process of treating the side walls and the front wall. the builder i am working with insists on placing 6-8ft tall x 2ft wide panels to cover most of the front wall and 5 on each side.
You are right. Refer to the published spec above, and you can see that your suspicion is spot on.i voiced my concern that the 1 inch might be too thin
Sorry, but he is wrong. Once again, the published specs show this.but he insists that they will be fine
Wrong there too. The Sabine equations deal with total surface area, not thickness. Thickness has an effect on the frequency range that each panel absorbs, but the total surface area of ALL absorption is what the equations tell you about, and you are way short on that. Once you figure out the places where you can get that much surface area, THEN you can think about what thickness and what type you need in each place, to get the right amount of absorption needed for each frequency range.with all the trapping i have 2 or 4 inch will be too much and the 1 inch will get the job done fine.
Well, yes, partly right. But a i said before, 1" air gap is not much use: 4" starts to useful, and 16" is very useful. Once again, it's an issue related to wavelengths and frequency. The further away from the wall you place it, the longer the wavelength you are treating, so the lower the frequency. You can see that reflected in the OC-700 specs above.he also says that since the framing is 2 inch thick there is approx 1 inch space between wall and the 1 inch fiberglass and that is better than having the panels flush on the wall.
You actually cannot talk about one without the other! The acoustic response of the room depends on all aspects of the room, not just the ones that he wants to talk about! :) It is the combination of treatments, and their thickness, and their characteristics, and their locations in the rooms, that matter: all together, as a total. So it does need to be said that the bass traps are too small for that room, and there are not enough of them, regardless of the issue with the mid and high absorption provided by the absorption panels on the walls. That said, your biggest single issue is the square room: that needs to be fixed before you do anything related to treatment. The room is basically unusable like that, regardless of how much treatment you put in it. The second biggest issue, is increasing the total area of absorption to get the required coverage to meet the ITU / EBU specs. The rear wall helps to approach the number you need, but you are still far short. I would suggest the ceiling for that. There's another hundred-and-something square feet up that you are not using right now, that would be perfect for what you need. - Stuart -so for wall panels (front and side walls) NOT bass traps in corners, any one care to chime in
wow thank you, i will review this in detail in a bit and respond accordingly.
however one of the first points you made i'd like to quickly address. regarding the room size and shape. i cannot change the size or shape of the room. this is an existing room we are talking about that i have been in for several years now. this is something i need for 2-3 years before i can be in a position to build from raw space and at which point i would consult multiple opinions from builders. in that case, i would shoot for 2-3x the square footage of the room.
i am well aware of all the inherent issues of the room i am in because it is too symmetrical and is a small recangular box.
the room is part of a large commercial facility which houses producers and jingle writers and dj/bands to practice. it is NOT build to be a true pro studio. they were meant to accommodate music people on a budget. i have been in the building for 6 years and career wise am not ready to spend 100k plus to lease out raw warehouse space (in new york city) and build properly.
with that being said, these rooms were build by an actual studio builder like 20 years ago and they were made with isolated floors, steel framing, walls were fully insulated and it was like a "budget" friendly environment. by no means perfect or anywhere near.
so my goal in getting into this project was to extend the life of my time here by another 2-3 years so i can build myself up to a position where it makes sense to pay high rent rates and spend a ton of money up front building a 400-450sq ft mix room and a medium sized live room from scratch. as you know, it gets pricey, and i'm just not ready for that right now.
however, like i said before, i hired someone (the actual guy who designed this entire building and has built medium grade studios in the past) to help treat this room to the best that it is possible.
his approach was we need to take care of the ceiling and he build those ceiling panels and angled them to reduce symmetrical reflections. i got my own bass traps for all the corners and the ceiling corners. they are THICK and well built, and as i said, the builder turned the skylight cavity into a huge bass trap itself.
i asked him why 1 inch on the walls though he said the following:
"I never use anything thicker than 1" for rooms this size as there is always a space usage factor. In addition
these panels are for absorbtion and diffusion. Thicker is not necessary ,I am certain of this.
Lets keep in mind you have a 24 sq ft bass absorber in the sky trap now and it will attract all low end that such thick wall panels would have been responsible for. "
in follow up conversations he is saying that they are not for the bass trapping and more to act as diffusion and absorption and 1 inch framed out in 1x2 with a 1 inch spacing between the wall and the panel would be sufficient since the room is so well trapped.
i'm just uncomfortable as my intuition tells my i should at least use 2". changing room dimensions is not an option. so 4 inch panels with 4 inch spacing etc. would really shrink my room.
so i'm kind of stuck here.
ps - so you understand what i have added properly: i have 14 of these as bass traps: http://www.readyacoustics.com/bass_trap_diy.html
as well as the skylight cavity
ps #2 -
[quote="Soundman2020"
Corners: 2x4 = 8 ft2, x 4 corners = 32 ft2
Clouds: 2x8 = 16 ft2, x 2 clouds = 32 ft2
Skylight: 4x4 = 16ft2, x 1 skylight = 16 ft2
Side walls: 8x2 = 16ft2, x 10 panels = 160 ft2
Total: 240 ft2
[/quote]
does this, or the sabin rating, take into account the thickness of the panels? because the bass traps are two traps behind each other. a 4ft H x 2f W x 6INCH deep trap and behind it is a smaller 4inch thick nested panel to fit into the corner.
all in all the real measurements, for now, not taking into account the depth are like this.
corners: 2x4 = 8ft2 x 14 traps = 112 ft2
clouds: 2x8 = 16ft2 x 4 clouds = 64 ft2
Skylight: 4x4 = 16ft2, x 1 skylight = 16 ft2
Side/front walls: 8x2 = 16ft2, x 15 panels = 240 ft2
total 432 sq ft
the corners are 6 inch thick 4 ft wide panels and like 4 inch thick 2ft wide panels.
the clouds are 1 inch thick
the skylight is really dense and the height of the cavity is about 4ft and it's all trapped.
the side/front walls are currently in question :?:
bump!
It's not that hard to do, actually. There are several simple ways that could be done. For example, building a new wall right next to one of the existing walls, or even just taking the drywall off one wall, furring it out a bit, and putting new drywall on. Etc. You don't have to actually physically move a wall: all you need to do is to move the hard boundary a bit.i cannot change the size or shape of the room.
Symmetrical is NOT a problem! On the contrary, symmetry is critical to a control room. No symmetry means no stereo image, thus no mix translation. The problem is not that your room is too symmetrical: the problem is that it is square. Symmetry is good: square is bad.i am well aware of all the inherent issues of the room i am in because it is too symmetrical and is a small recangular box
Perhaps that's not a good choice. If he designed the room square in the first place, it makes you wonder...i hired someone (the actual guy who designed this entire building and has built medium grade studios in the past) to help treat this room to the best that it is possible.
Once again, there is NOTHING WRONG WITH SYMMETRY! As I mentioned before, a control room MUST be symmetrical. The left half MUST be a mirror image of the right half. This is just plain logical: if you want an accurate environment to mix in, then both of your ears must hear the same acoustic "signature". If your ears are hearing different acoustics on the two sides, then you will subconsciously try to compensate for that in the mix, and while the mix will sound good in that room, it will sound lousy and imbalanced everywhere else. So STOP what ever it is you are doing to change the symmetry, undo that, and get your symmetry back again, the way it should be.his approach was we need to take care of the ceiling and he build those ceiling panels and angled them to reduce symmetrical reflections
That's good, and is a large part of what all small rooms need. But it won't be enough. With perfectly overlapping modal issues all the way up the spectrum, the entire room is one giant comb filter. No amount of treatment can fix that. The fundamental shape is flawed.i got my own bass traps for all the corners and the ceiling corners. they are THICK and well built,
You said that it is roughly in the middle of the ceiling, right? So how on earth can it be a BASS trap, when there's no bass that needs trapping at that location? Bass modes ALWAYS terminate in the room corners, not in the center of the ceiling. That's why bass traps go in corners: because that's where the bass issues are, and that's where they can be treated the most effectively. That is not a bass trap: just a very, very deep absorptive panel, and it is probably also a tuned cavity, since it was basically just a hollow shaft before. Hard to say if it is tuned to a useful frequency, but most likely not.and as i said, the builder turned the skylight cavity into a huge bass trap itself.
Well, no, they are not doing any diffusion. Absorption absorbs: it does not diffuse. Sorry. You might want to suggest that he should buy a copy of "Master handbook of Acoustics", by F. Alton Everest, so he can learn the difference between how absorbers work, and how diffusers work. Besides, that is a small room: it does no need diffusion: it needs absorption. And 1" of 705 will do neither. Just look a that table that I posted, published by the manufacturer of the stuff! I rather think that the manufacturers knows how his product works, just a bit better than your builder... The manufacturer says that it has no useful low frequency absorption when used in the manner your builder is suggesting. Sorry, but the laws of physics are well know, and the behavior of absorption is pretty well understood. It does not work the way you are hoping it will work. Your suspicions are correct: 1" is way too thin, and 705 is way too dense for what that room needs."I never use anything thicker than 1" for rooms this size as there is always a space usage factor. In addition these panels are for absorbtion and diffusion.
And I am certain he is wrong! After he gets his copy of "Master Handbook of Acoustics", tell him to read chapter 7, (starting on page 129) then chapter 9 (starting on page 179). He'll also need to read chapter 13 (page 267) to find out about how diffusion works, then chapter 15 (page 317) to understand why why he is suggesting is totally wrong for your room. Chapter 21 (page 429) would be a good place to go from there."Thicker is not necessary ,I am certain of this. "
No you don't have that. You said it measures 4 feet by 4 feet, so it it only 16 square feet, and since it is in the wrong place, it is not even a bass trap at all: it is just an absorption panel.Lets keep in mind you have a 24 sq ft bass absorber in the sky trap now
Oh boy. I don't even know what to say about that. This is just garbage. Sorry, but there's no polite way to put it. Holes in the ceiling stuffed with insulation do not "attract" anything (except maybe dust). You cannot "attract" sound to a device. Sound is not like a fish, that you can put up some bait and hope the sound will head that way!!! Sound is simple a constantly interchanging field of air pressures and particle velocities, and you have to put each device in the correct part of the room where it will find the correct combination of pressures and velocities for each problem that needs treating. Once again, your skylight filled with insulation is nothing more than a 16 square foot absorption panel.and it will attract all low end that such thick wall panels would have been responsible for.
Once again, they will not diffuse anything, since insulation is not diffusive! Insulation absorbs: Diffusion is totally different. Insulation works by the fibers being moved around by the sound waves passing through, and turning the sound energy into low-grade heat energy. Diffusion works by bouncing different parts of the same wave in different directions and/or with different timing and phasing. You cannot do that with absorption!in follow up conversations he is saying that they are not for the bass trapping and more to act as diffusion and absorption
Sorry, but it is NOT well trapped. It is partly trapped. I would suggest that you run the REW acoustic analysis program on that room, and post the data file here so we can show you what is wrong with the room acoustics, and tell you how you can fix that.... 1 inch framed out in 1x2 with a 1 inch spacing between the wall and the panel would be sufficient since the room is so well trapped.
Your intuition is right! But the minimum should be 4" on first reflection points. Thicker or thinner panels might be needed at other locations, but at the first reflection points you need them thick, and not too dense.i'm just uncomfortable as my intuition tells my i should at least use 2".
Then don't space them! Just us 4" panels flat against the wall. That won't be as effective as spacing them, but it will still work quite well. As shown by the acoustic data table I posted previously for that product. Also, it should be 703, not 705. 705 is too dense, and will do nothing for bass. 703 at least has some effect on bass.so 4 inch panels with 4 inch spacing etc. would really shrink my room.
They should work fine, since they are supposedly made from 703, but at $356.50 per pair, it seems a little expensive! You could have made your own for a fraction of that price. And the claim they make is rather curious: "Absorption range: 20Hz – 20kHz ". 20 Hz? Really? From a 4" panel of 703? I'd like to see the independent test data from a reputable acoustics lab to back up that claim! I did look for it on their web site, but strangely enough I could not find any place where they have that kind of data. I wonder why?I have 14 of these as bass traps:
No, because that is irrelevant to the issue. Thickness by itself has no effect on sabine equations. It only matters indirectly. What matters, as I said, is that you need a total of 428 square feet (surface AREA, not thickness) of perfect absorption to get that room under control. Note what that says, carefully: "SQUARE FEET OF PERFECT ABSORPTION". "Perfect absorption" means that all frequencies are absorbed totally, completely, and evenly, 100%. There is no such thing in real life. The only "perfect absorber" is an open window facing infinite empty air on the other side. That0s why acoustic manufacturers publish charts, tables and graphs that show how close to "perfect" their products are. Thicker absorption is generally a bit closer to "perfect" than thinner absorption, since it absorbs a lager amount at low frequencies. Thin absorption does not do that, so it is less perfect. But none of that changes the total amount that you need in your room, since that is expressed as square feet of absorber that is directly facing the room. If you put another layer behind the layer that is facing the room, you have NOT increased the total surface area: all you have done is made it a bit more perfect, so it absorbs better at lower frequencies. In other words, you improved the quality, but did not change the quantity. No matter how thick it is, you still need 428 square feet of surface area facing into the room. And since real-world absorption is no perfect anyway, you actually need much more than 428 square feet.does this, or the sabin rating, take into account the thickness of the panels?
That's very good, but still not enough for your room, since not only is it small, it is square.the corners are 6 inch thick 4 ft wide panels and like 4 inch thick 2ft wide panels.
:shock: :?: :!: Then they are useless! Sorry, but a 1" cloud is not a cloud at all. Clouds should be at least 4", and might even need to be hard-backed. In fact, in your room I would definitely make them hard backed, to perhaps break up some of the modal issues a bit, and I would put another 4" above the hard back, for extra absorption.the clouds are 1 inch thick
Dense? dense is bad for bass trapping. High density absorption is good for high frequencies not low frequencies! Low density absorption is much better for bass. So your skylight is probably acting like a high frequency absorber, and is certainly not a bass trap. -- I would really, strongly suggest that you should run a REW analysis on your room, as it is right now, and post the data file here so we can analyze it for you. That will tell us exactly how your room is reacting right now, and based on that we can tell you what you need to change to make it work. - Stuart - PS. You still did not do this: read the forum rules for posting (click here). Please read that, and do what it says.the skylight is really dense and the height of the cavity is about 4ft and it's all trapped.
sorry for the bump, as far as rules, what else is there you want me to read? i included as much detail as possible in my post. location? i am located in new york city.
back to the thread: i'm not sure if i explained this properly, i cannot knock down walls, it is in a huge complex with 30+ rooms exactly the same size and i am a tenant. they do not allow to change walls or break down walls. unless i'm not understand your reply correctly about putting up new drywall. or moving the hard boundary. how would that be done, what would it accomplish? the room dimensions and size would stay the same no? just the angles would be different or i would gain a few inches.
as far as the bass traps i bought, they were for a pack of 2 so its like $175 each. and they are 6 thick with a nested panel behind it of 703 at 2 inches thick.
so i'm 100% on not doing the 1inch on the walls. my only concern is the space is small as it is and if 4" of air space is ideal then i can say for most of the walls i cannot put 4inch 703 + 4inch air space. it would take 8 inches off each side shrinking the studio a lot more than it is now. the only thing i'm trying to figure out is which is more effecitive? 4inch on a wall, or 2inch panels with 2 inch air space off the wall? how about 4inch panels with 2inch air space. 4inch panel + 4 inch space is just not doable i dont think. i'm sure any of the prior three should work.
so this is my idea wanted to run it by you. i am going to be making these myself...
front wall ill have 4inch panels flush on the wall.
side walls in the front (by the speakers) will each have 3 side by side 2x8 panels 4inch thick with 2 inch air
the side walls further behind in the room which will be two per side in the mid-rear will be 2 inches with 2 inch air
as far as the clouds, the 1inch 703 is framed out by 1x2 wood so there is another inch there. i can add an inch of 703 or a 2 inch and it sticks out a bit. since they are hung from ceiling they wont fall even if it goes over the wood. thoughts?
As the rule says, that is supposed to go in your user profile, not just in a post.as far as rules, what else is there you want me to read? i included as much detail as possible in my post. location? i am located in new york city.
Bummer. Will the allow you to built a second temporary wall, next to the existing wall? One that you can take down again when you leave? If not, then your only option is to build angled modules that sit on the floor and go up to the ceiling. They don't need to be very thick, and can incorporate the treatment that you will need as well. In that case, I would go with slot wall modules, angled slightly, for the front half of the room. That would be enough to break up the lousy modal distribution a bit.they do not allow to change walls or break down walls.
If you move the wall, or build a second wall next to it, or even fur out the existing wall, then the room dimensions DO change, and that's what matters. As long as you can change the width of the room by a few inches, that's all that you need to break the curse of the perfect square. Those slot-wall modules I described above would do the trick. Simple, cheap, effective, and easy to take with you when you go. And maybe re-use at your next place! :)what would it accomplish? the room dimensions and size would stay the same no? just the angles would be different or i would gain a few inches.
Like I said above: then don't do that! Just put the 703 flat against the wall. That is called "A Mounting". As you can see from the table I posted originally, even done like that it is still very effective. 4" of 703 done like that has an absorption coefficient of .84 at 125 Hz. 1" 703 has only .11. Therefore, as you can see for yourself from the chart, 4" 0f 703 is eight times more effective then 1" of 703. The number's don't lie. You could even go with 3" 703 if you want to save more space: that is still reasonably effective, with .53. But 2" is not advisable, as you can see from the chart: barely better than 1".i cannot put 4inch 703 + 4inch air space.
That would be pretty good. You could even consider 3" panels with a 2" gap, if space is that tight, but 4" panels over a 2" gap would be your best option.how about 4inch panels with 2inch air space.
Yes. Place those right between the speaker and the front wall, with the speakers right up against the panels. In your case, the speakers should be set up so they are about 3' 6" feet from the side walls, angled inwards at about 30° to face the mix position. That will make the speakers about 5 feet apart, and put your head about 5 feet from the front wall, which is about as good as you can get in that size room. The speakers should also be set up so they are 47" above the floor. PLEASE NOTE! All of these measurements refer to the ACOUSTIC AXIS of the speaker, not the top or bottom of the box. The manual for your speakers should tell you where the acoustic axis is. If not, then let us know what make and model they are, so we can tell you roughly where it is. Also, the speakers must be mounted on very heavy (massive) speaker stands behind the desk, not on the desk or meter bridge. That's a very common mistake in many control rooms: speakers look cool on the meter bridge, but acoustically that's a lousy way to set them up.front wall ill have 4inch panels flush on the wall.
Sound good. The most important thing here is to make sure that your first reflection points are covered. You could even angle those panels a bit, so they have 2" air gap at the edge towards the front of the room, and no air gap at the rear edge. That helps for two reasons: it helps reflect some of the highs more towards the rear of the room (away from your head), and it also makes the panel more broadband, working more effectively across a wider range of frequencies. You don't HAVE to do that if you don't want, but it would help a bit.side walls in the front (by the speakers) will each have 3 side by side 2x8 panels 4inch thick with 2 inch air
Sound fine. Leave some empty wall between them, so they are not right next to each other. Provides better overall coverage, and maybe also some slight diffusion and diffraction.the side walls further behind in the room which will be two per side in the mid-rear will be 2 inches with 2 inch air
That would work. Add 2" of 703 to that. And if the chains that it is hung from are string enough, then put a thick piece of plywood on top of the frame (facing the ceiling), then another 2" on top of that. Then adjust the chains sp the entire thing is angled at about 10°, lower down at the front (over the speakers), and higher up over your head. Photos of the room the way it is right now would also help, but your best bet is to do a REW analysis. Download REW: it is free! It is simple to use. Then post the data file here, and we can analyze it for you. - Stuart -as far as the clouds, the 1inch 703 is framed out by 1x2 wood so there is another inch there. i can add an inch of 703 or a 2 inch and it sticks out a bit. since they are hung from ceiling they wont fall even if it goes over the wood. thoughts?
thank you so much. i emailed the builder i was using and told him i will do the rest myself.
i have gotten more information here than everywhere else i have looked so far and information based on facts rather than people just saying things. my intuition as an audio engineer rather than an acoustician aligns itself more with what you are saying that what i have been told thus far.
what i'm going to do is take very detailed measurements and my best attempt on graph paper to draw out the room and take pictures and upload the entire thing here to get as much help as possible as I DIY this. what has been done with bass traps and clouds has been done but I want to address the walls accordingly.
Great! :) That's what we are here for... to help out people who get stuck on acoustics issues.
The bass traps are fine, and should work very well, but the clouds can probably be modified very easily. Clouds are pretty much always just hung from chains in most studios, so you can unhook the chains, bring the clouds down to the floor, nail a piece of plywood on top of the framing, put some 703 on top of that, re-attach the chains, and lift it back into place. Then just make the chains at the front of the room a bit longer, so that end is lower down. Simple! :) - Stuart -what has been done with bass traps and clouds has been done but I want to address the walls accordingly.
yeah i have taken them down already a few times to paint ceiling and to relocate track lights. i can easily add another sheet of 703 without even using plywood. there is a 1inch gap currently between the 1inch 703 and the 2inch wood frame. so it will fit another 1inch 703 or even 2inch with it sticking it out a bit on the top. but again, they are mounted hanging so they dont fall out of place. i will take pictures as i said so you guys can see a better idea of what i have. they are spaced several inches from the ceiling and at angles.Great! :) That's what we are here for... to help out people who get stuck on acoustics issues.The bass traps are fine, and should work very well, but the clouds can probably be modified very easily. Clouds are pretty much always just hung from chains in most studios, so you can unhook the chains, bring the clouds down to the floor, nail a piece of plywood on top of the framing, put some 703 on top of that, re-attach the chains, and lift it back into place. Then just make the chains at the front of the room a bit longer, so that end is lower down. Simple! :) - Stuart -what has been done with bass traps and clouds has been done but I want to address the walls accordingly.
The plywood is not there so you can add more insulation! It is there to try to help break up your terrible modal problems just a little bit. In effect, a thick, heavy sheet of plywood interrupts the path of the sound waves around the room, and re-directs them slightly, just enough to make a small difference. Your cloud basically works in the vertical direction, but your modal issue are in the horizontal direction, which is why you need to tilt that cloud down at the front quite a bit, so there is at least some angle on it, into the horizontal. Looking forward to those photos! - Stuart -i can easily add another sheet of 703 without even using plywood
fyi i'm in the process of installing all the bass traps in the corners. what a nightmare that was. i didn't understand that this whole corner mounted system was meant for vertical mounting only and not horizontal on the wall-ceiling corners. so i had to rig my own installation with hooks and a lot of DIY stuff. almost done with the trap installs (there are 14 all through the room everywhere there is a corner) and i will take pictures shortly.
quick questions
1) you asked before for speaker types. i have pair genelec 1031a with a 7060b sub. also have ns10m studio as a second pair.
1) is 4" panels with no air better than 2" panels 2" air?
2) i can do my best to post pictures and measurements but ultimately especially for listening and positions and testing is there anyone that can be recommended in the nyc area that can do hourly or some sort of consultation fee to just check over everything in person? there are the high end studio builders based in this area such as fran manzella and wsdg etc. however i don't know if this is too small of a project for them just to "check" a room. after my recent experience with the unnamed studio builder who has some relatively decent credits he was not thorough at all or scientific in his approach and was just interesting in doing his job and not answering questions or being detailed in his approach. all of his suggestions were knocked down and i am skeptical of the work he already did. i'm assuming big names like these don't have those issues or at least take the time to communicate more and explain their work. this guy would get agitated the minute i started asking questions or suggesting things. as evident by this thread all of my concerns were valid and correct as it seems he had not consulted me properly. if it means me paying to sleep at night knowing my room is as good as it can be within the physical space it's worth it for me. so yeah, any suggestions would be appreciated.
:shock: Ooops! Sorry! I should have warned you about that! There are techniques for doing horizontal superchunks: I should have pointed those out for you. BUt it sounds like you got there anyway. One thing I would do on all of your corner traps is to put a piece of plastic across the front, before you put the cloth cover on. Use ordinary 6 mil plastic, the kind that contractors use inside walls to make vapor barriers, and you can find on big rolls in Home Depot. So staple a layer of that to the framing across the front face of the trap, then put the cloth cover on. There are two reasons for that: one is acoustic, the other is practical. Acoustically, it reflects some of the high frequencies back into the room, so you don't lose too much of that (keeps the frequency response of the room more even), and second, it keeps the fine fibers inside. Over time, the insulation will shed many tiny little fibers that can get into your equipment and damage things like faders and pots, and also block air filters and gum up cooling fans. So keeping those fibers inside the traps is a good idea!i didn't understand that this whole corner mounted system was meant for vertical mounting only and not horizontal on the wall-ceiling corners.
Nice! According to Genelc, the acoustic center of your speakers is 9 1/4" up from the bottom of the box, and 5" in from the left side. Imagine a line poling straight out the front of the speaker at that point, and that is your acoustic axis. All of the measurements I gave you for the position of the speakers refer to this acoustic center and acoustic axis. Like this:i have pair genelec 1031a with a 7060b sub
4" is slightly better for high frequencies, about the same for low frequencies. On your last point, I'll PM you about that. It actually can be done by "remote control"... - Stuart -1) is 4" panels with no air better than 2" panels 2" air?