Looks like the decay is steadily climbing. Any idea about the dip around 171 hz...It seems to be getting worse. Not alarmed. Just wondering what you think of it.
CR Treatment and Tuning---The home stretch!!
Originally posted at johnlsayers.com, topic 21368.
I know I'm pushing my luck here but any chance of a weekend project to keep me busy? :mrgreen: :shot:
All in good fun... :lol:
What a killer explanation :) Thanks! Im still far from building acoustic treatment, but boy.. Will this thread help me with engaging that! I guess ill need some private counseling when the measurements start and i will actually start designing the things :)F=54.59 * SQRT (height-of-hole / (height-of-volume * depth-of-volume * effective-neck-depth) ) * 1000 All of those measured in millimeters. The last term, "Effective-neck-depth" refers to the thickness of the slats plus a "mouth correction factor". Remember I mentioned the slug of air trapped inside the slot? Well, the slug that moves in and out is actually bigger than the slot: it includes some air on either end, just outside the slot, so the "effective depth" of the slot is the thickness of the wood plus 20%, because it extends about 10% more in either direction.
My thought was that it had to be around 5 milimeters thick, correct? And you cant glue the insulation to the slats very firmly to not compress it too hard.For this we used "pink fluffy" insulation, which Frank pulled apart even further with his fingers, to make it very light. 701 would have worked, but the thinnest you can get is 1" thick, and that's too much for here.
Indeed. I havent thought about that. One thought: I am designing a large desk in my studio that will hold equipment and some gear. I did design it as low profile as possible but I know for sure it will still present some acoustical problems. I designed everything with smooth angles and with comaprtmens along these angles so i would later be able to add insulation or other treatment in these if i need. Do you often treat the front of studio equipment to prevent reflections from its surfaces? ANd how thick do you treat them if you do?But it won't be the deepest dips that I look for: it will be the modes that ring the longest (decay the slowest). Dips MIGHT be modal, but they might also be SBIR, or reflections. I don't go after dips at this stage, usually. If it turns out that Im' left with some modal dips still at a later stage, I might go hunting for them in other parts of the room to see how bad they are, then decide what I'm going to do about it.
I see why you reccomend that :) But I will choose the hard way if need be :) With some help here, some dedicated time on reading and careful craftmanship - I think ill be able to reach the goal of at least a good sounding studio :)One word of warning: It sounds real easy to do, but in reality it is not easy at all! I do not encourage first-time studio builders to go this route: designing and using tuned low frequency devices is hard, even for experts. I much more strongly recommend using only absorption for first-time studio builders, since it is so much simpler, and really hard to get it wrong!
Tell me about it.. Its like guys just put any type of fu*** up weird looking thing in front or behind them just because it 'looks cool'. With your point in mind - it only looks cool if you have no fucking idea what youre doing :))However, this fact does not seem to stop home studio builders from splattering diffusers all over their rear walls of their small rooms! You see that EVERYWHERE! Ignorant people doing silly things to their studios. The problem is that they see pictures of pro-level studios with diffusers on the rear wall and think "That looks cool! If they need those thingies, then I need them too!" So they go buy them, without realizing what damage they are doing. And of course, the manufacturers don't bother telling them that it's a bad idea! They just want to sell more diffusers, so they don't care who buys them....
What range of accuracy are you aiming at exactly with Franks room? :)It's complex to tune a room, when you want it to be very accurate, as Frank does. You can't just hang a few things on the walls because you saw them in a photo of a high-end studio, and figured you need them too! For high precision, it's a long process, done one step at a time. For someone like John, who has a lot more experience than I do(!), he can skip some of those steps by just using his knowledge and expertise gained from many, many past studios. But I like to test every step, to make sure it is working as expected, before going on to the next step. Maybe when I have as much experience as John does, I'll be able to do the same! Until them, I'm a "repeat tester"... .)
Great idea! But these usually come in very fixed widths and depths. I assume knowing how wide and deep they are you would differentiate the distances between them to get the effect you need? All in all - a great thread, Stuart :) Thanks for sharing you experience and know-how! It is very much appreciated :) You have a good weekend :) Cheers.Especially those curved log siding ones! They would be very good for avoiding specular reflections from flat planks.
It would be good if you start posting your initial designs in your thread, so we can get an idea of where are right now, and where you want to go. Sometimes it-s good to have some extra pairs of eyes "looking over your shoulders" to see what you are doing, and maybe notice things you hadn't seen.Im still far from building acoustic treatment, but boy.. Will this thread help me with engaging that! I guess ill need some private counseling when the measurements start and i will actually start designing the things
It's about half an inch, roughly 12mm. Thick enough to rob the slug of energy on each pass, but not so thick as to over-damp it. Going back to the "kid on a swing" analogy: you do want him dragging his feet through the water, and maybe even his ankles too, but you don't want the water up to his waist!My thought was that it had to be around 5 milimeters thick, correct?
You can, as long as you are careful, and assuming that the slats are wide enough: just a thin bead of glue up the middle of each slat, but taking care to not get glue anywhere near where the air will be moving. Another option is to use something like chicken wire stapled to the side walls, and shaped to hold the insulation in place with just light pressure. [quote I am designing a large desk in my studio that will hold equipment and some gear. I did design it as low profile as possible but I know for sure it will still present some acoustical problems. I designed everything with smooth angles [/quote]By careful use of ray-tracing, you can make your desk do the same as the RFZ concept, and redirect reflections away from your head.And you cant glue the insulation to the slats very firmly to not compress it too hard.
Where necessary, I do use insulation on the rear side of the entire desk. Studio Three, for example, has about 4" of 703 on the front: I don't recall exactly... it might be only 2". But it was necessary to deal with some reflections from there that were getting reflected a second time from the soffits, and getting back to the mix position. There's also insulation on top of the wing surfaces, for the same reason: It's fairly dense and covered with thin carpet, so there's a reasonably solid working surface on those, at least for putting down your coffee mug or pizza plate...Do you often treat the front of studio equipment to prevent reflections from its surfaces? And how thick do you treat them if you do?
That depends on him! We can take it as far as he wants to go until we hit the physical limitations of the room and equipment, if he wants to do that. But there's a point of "diminishing returns", where each successive tweak makes smaller and smaller changes to the response. You get to the situation where you can no longer hear any change at all, even though the graphs are getting flatter and smoother: once you pass that milestone, there's not much point in going further, except for "bragging rights". If the acoustic response fully meets ITU BS.1116-3 specs (or EBU TECH-3276 specs, if you prefer), and you can't hear further improvements, then there's no more acoustical reason or psycho-acoustical reason to carry on... unless you just want to be able to say that your room response is perfect! It takes time to do each new tweak, and of course "time is money" ... in this case Frank's money, so when he runs out of money, then his room is done! :)What range of accuracy are you aiming at exactly with Franks room?
Right, but what we are building now with Frank is not a tuned slot wall. It looks like it, but it is not sealed, and the gaps are far too wide to be tuned. Yes, it is "tuned" in a different sense: the width of each slat is designed to reflect a certain frequency range, and the gaps between them allow lower frequencies through, to be absorbed. So it is tuned in that sense, but not as a Helmholtz device. - Stuart -Great idea! But these usually come in very fixed widths and depths. I assume knowing how wide and deep they are you would differentiate the distances between them to get the effect you need?
We are getting too many specular reflections like this, with those flat planks, so I'm thinking of taking this in an entirely new direction.... if you are up for it! :) The construction gets to be a little complex, and a little boring at the same time, but I think it's the right approach for the rest of the side walls. It will also look really cool! The basic plan is this: another slotted poly, but with very different design: a whole bunch of 1x1s or maybe 2x2s, or 2x1s, or something like that, standing up vertically, but with the front edge rounded (or beveled), and built similar to the huge rear monsters that we already did in the rear corner, along a poly-cylindrical path, shaped like a slight "wave" coming out of the wall. It's hard to describe in words, but this is the basic concept: However, yours would not be that deep, and would not follow that circular pattern: it would be a reverse catenary curve, that starts out smooth and tangential to the wall, then bulges out a bit at an increasing angle, then curves back in again, ending up tangential again. You don't have much space to spare inside the room, so I can't bring it out very much, but there's some room to do that. It will be a smooth organic curve, not a sharp angled curve. Acoustically, this would be the best option, since it provides reflection and diffusion at the same time, without being specular. We can get the needed increase in mids and highs, and probably also take another bight out of the SBIR, with the curve itself. The curve that the slats would be built along, would be more like this: What do you think? It's slower to design, slower to build (boring, yes), but I reckon it's your best bet. And it will look rather nice... - Stuart -I know I'm pushing my luck here but any chance of a weekend project to keep me busy? All in good fun...
I suppose we should do what's best for the room... I say okay.. I'm not sure exactly what we're going to end up with of course but I trust you on this one.. what needs to happen next?
So I would have to round off the faces of each board? I'm guessing the only way I could do that is by sanding..That sounds painstakingly horrible. I'll have to figure out a way to do it....hmmm.
Flat boards can't follow the curve? Faces definitely need to be curved? I'll try to figure something out..things always seems harder at first glance.
If we could do beveled, that would be good. That's a no brainer on the table saw...
Also, I can get 1x2 boards in 8' for cheap. Would like to go that route if we could. So it looks like my vote is beveled 1x2 boards! :)
It's MUCH easier with a router! :) Use a half-round router bit, sometimes also called a "bull-nose" bit. Another option is to use a quarter-round bit on both edges, and leave a small flat surface between: Or maybe even something like this: There's a huge variety of router bits out there, that can be used creatively to get rounded profiles on the end of the wood.So I would have to round off the faces of each board? I'm guessing the only way I could do that is by sanding..That sounds painstakingly horrible.
Yes, flat boards can follow the curve, but that's not the issue: I'm trying to avoid specular reflections in general, and get better diffusion too. This is the concept: That's from a mastering studio that I designed a while back, currently under construction. So no photos yet of the finished product. But that's basically just 1" wide lumber routed with either a 1" bull-nose bit, or routed twice with a quarter-round bit (once on each edge). That gives rounded surfaces on the front of a rounded surface, so no specular reflections at all. Just overall reflection, with scattering (you can't really call it "diffusion", technically, but it's very similar). I might go with slightly wider slats that have a bit of flat in between the two curve edges: not sure yet. I just wanted to get your OK for the concept. - Stuart -Flat boards can't follow the curve? Faces definitely need to be curved?
Of course, what was I thinking...I tell ya...first glance and all.Should have thought of that. :roll:
So embarrassing :oops: :)
Still, if we can work with 1x2's that would be great for ease of access and price. They're furing strips. I used them on the diffusers in the LR.
I'm guessing that I would shape ribs for the wall contour. I would then attach the boards to the contour and wallah! We have a curvy wall. I did the contour on the LR absorbers by rough cutting then sanding the shape in on a belt sander with a 1" wide strip. I can get concave curves with that for sure.
Actually drawing the complex curve line on the wood ribs will be the trickiest part, but I'll figure that out. Doesn't seem like it will be too boring. Maybe it will boring to model it in Sketchup?
1x2 nominal? Actual dimensions 3/4 x 1 1/2"? Please check the real dimensions, to be certain, but that sounds like a good possibility. Rounding the edges off that with a 3/4" quarter round bit would leave a no flat in the middle, or rounding with a 1/2" quarter round bit would leave a 1/2" flat... Sounds like a good option! - Stuart -if we can work with 1x2's that would be great for ease of access and price.
YEs,
3/4 x 1 1/2 actual. Always annoys me that the industry adopted that standard...can't call things what they are :roll:
Awesome though! I think we're already getting on track...
Check out the crazy wall Universal Audio did down the street in they're LR. I met the contractor who built it and he gave me a copy of construction pics back in 2015...I'm gonna be cool like them!!! :lol:
Cooler, by far! :) - Stuart -I'm gonna be cool like them!!!
How are we looking for this week?
Working on it! :)
- Stuart -
If it saves you time I probably only need the layout line for the curve of the wall... I'll have to trace that and cut it and shape it to make the ribs which will be the shape I'm assuming.. Once you determine the radius of the board surfaces, that should just about do it for me I think.. I may not see the whole picture of course so it may be moot.
It's a bit more complex than that: I've gone through probably a dozen curves with different slat sizes and spacings, trying to get this to work out both acoustically and visually. The limiting factor for part of the curve is the location of that HVAC register on the ceiling: the slats can't come over more than that. That's why I had to discard several curves. But I think I'm getting somewhere now...
The bad news is that there's no way we can do this with slats that are only 1 1/2" wide: they need to be considerably wider that that, or they don't treat the frequency ranges we need to treat. They will probably have to be at least 3" wide, maybe even more: perhaps 4 1/2". If you have a biscuit joiner, you could maybe still use the 1x2's, by butt-joining them together in pairs or triples. Or maybe just buy wider lumber. I'm working on the slat width/spacing aspect right now, and as soon as that's done I'll send you the design for comments. It's proving to be rather tricky!
I'm also half-considering adding a horizontal soffit at the top, like you asked about originally, to match the live room.... If I can fit that in, I might do it. It could look good.
Getting there! But slowly....
(Rome wasn't built in a day!)
- Stuart -
Well that is an occupational hazard of being in uncharted territory...
I know this will have to be sorted and that will take some time.
In all fairness though, my studio was definitely not built in a day. 8) LOL
If we can avoid doing the soffit I would rather save myself the hassle of building it. I'm all for it if you feel like we really need it though...
Yeah, it would be great, but the problem is that im not very good with Sketchup. Also, at this time theres not much free time i can spend on learning or developing the design. And since the inner leaf of the room has been finished and now guys are working on the flooring and later will work on the soffits - I am definitely not sure how long would it take for me to draw in every detail of the current build stage.. What details do you need except for dimensions, framing, wall and ceiling construction to be able to provide professional advice on acoustic treatment?It would be good if you start posting your initial designs in your thread, so we can get an idea of where are right now, and where you want to go. Sometimes it-s good to have some extra pairs of eyes "looking over your shoulders" to see what you are doing, and maybe notice things you hadn't seen.
If you are looking for professional consulting services on designing your own studio, then that would be better handled off-line, not on Frank's thread: PM me, and we can talk. Also, feel free to start your own thread, where we can discuss your design and build without hijacking Frank's thread. I'd love to be involved in your project, either way, as it sounds interesting. - Stuart -What details do you need except for dimensions, framing, wall and ceiling construction to be able to provide professional advice on acoustic treatment?
I think I have a workable solution for you. I'm not 100% happy with the looks, but I'll eave that judgement up to you...Well that is an occupational hazard of being in uncharted territory... I know this will have to be sorted and that will take some time.
OK, no soffit! No problem. Just floor to ceiling slats: Four views, to give you the concept. Those are 1x5 slats (in other words, 3/4" x 4 1/2" in real dimensions). They have to be that big, unfortunately, to get the acoustic response we need down to low enough frequencies. Visually I would have preferred 1x2 or 1x3 slats, but no matter how I tried, I couldn't get them to work. I did some "logarithmic" spacing to make it more interesting visually, and also for acoustic reasons, so the gaps at the outside edges are much wider than the gaps in the middle of the "hump". These are designed to accomplish three things: 1) restore the decay times for the mid range and highs that we are currently missing, 2) broad low frequency bass trapping (similar to the "monsters" on the rear corner), and 3) help a bit with the modal and SBIR issues down low. The slats are tuned, especially the "hump" section (not so much the extremities), broadly across the low end from around 50 Hz to around 250 Hz, but gently, not aggressively. It turns out that the thickness of the slats is not critical here: anything in the range 1/2" to 1" would work, but peak performance is at 3/4". So 5/8 or 7/8 would also be just fine. Let me know what you think. Hopefully you don't hate it too much, since there's not much room for adjustment! The limiting factor for the "hump" in the direction towards to the couch is the HVAC registers, and in the other direction (towards the doors) it is leaving a decent amount of space to walk through and generally hang around the room. The "hump" extends nearly 9" away from the stud faces. That's about the only thing I have much control over: I could make it a bit flatter, down to about 7", or even bring it out to about 10" if you wanted, but to me it seems that the best compromise is where it is, at 8 7/8" inches. - Stuart -If we can avoid doing the soffit I would rather save myself the hassle of building it. I'm all for it if you feel like we really need it though...
I don't find it to be ugly...its mostly the feeling of space I care about. I'd like to go as flat as possible without mooting the point of it. I'm guessing you mean that around 9" is the best compromise between space and sound? Those boards will be pricey but thats that...
Of course the sonic goals take precedence...Not my week, I just gotta speeding ticket to boot which wiped out my uber earnings for the week. :( The money is always going somewhere I tells ya!
Thanks for the effort though Stuart. :thu: Any ideas how I might be able to work with space for outboard gear? Probably a desk integration at this point...
can we make the boards 8' instead of ceiling to floor? It would help the cost tremendously and be easier to acquire. For instance, They have 1x6x16 that they will cut down for me but they won't cut them to 10'....I'd have to pay for the whole 16' board. With a 1x12 I could get 2 boards, but its quadruple the price. no good options for me above 8'...hmmm.
ohhh. I also forgot..I have 2ft power strips on that go on each wall...The outlets are are code. I can modify to fit those of course. Just letting you know.
I did just talk to a guy that said that they would rip 2x6 lumber down to 1x6 for me... its standard doug fir..Probably not as pretty but I can paint it..
I'm tempted to paint the wood so I can keep the room light. I don't want to light stain wood in that volume. I stayed in a log cabin years ago that felt really dressing after awhile. It had that affect going on. Interesting kit house though.
:yahoo: :thu:I don't find it to be ugly..
Right! That's why I wanted to use smaller slats, as they look less imposing and give a more airy, spacey feel, but they just don't cut it, acoustically.its mostly the feeling of space I care about.
Right. More would be better (deeper "hump" = lower frequencies), but I can probably get it down to between 7" and 8" by narrowing the gaps between those slats a little. I'll give it a try, and see what comes up...I'd like to go as flat as possible without mooting the point of it. I'm guessing you mean that around 9" is the best compromise between space and sound?
Well gee, that wasn't such a good idea! :) Painful....Not my week, I just gotta speeding ticket to boot which wiped out my uber earnings for the week.
I once heard the owner of a small boat say that the real joy of owning a boat, is that it's a really nice shaped hole in the water, into which you throw all your money... :) I guess the same could be said of a studio! 8)The money is always going somewhere I tells ya!
Yep. I'd put it all in the desk. I asked you if you had any ideas for your desk a while back, but I guess you didn't see that. In the next update I'll put in nice mastering style desk that would work well for your room: low profile, small, very good acoustically, but plenty of rack space. It might or might not work for you, depending on how big you want your console to be (assuming you plan on using a console?). If it's just a DAW you want with outboard gear, or a DAW plus a minimal console, then this desk would work great. It's configured for a master studio that I designed for a customer in NC, but I can easily swap out the center section to insert your choice of console, if you like the general idea.Any ideas how I might be able to work with space for outboard gear? Probably a desk integration at this point...
That's why I was thinking of the soffit! If it only goes up to 8', then you'll need something to cover the last 15" at the top: it would look strange just having it end in mid air, with nothing above. One option would be to continue the same curve up to the ceiling with just fabric and fill in with insulation behind, which would work great, acoustically, but if you wanted to frame it with wood, that would be hard to bend wood to follow that shape. That's why I was thinking of a boxy soffit: the slats would end at the bottom surface of the soffit, and the soffit could be wedges shaped, so it doesn't look to overpowering.can we make the boards 8' instead of ceiling to floor? It would help the cost tremendously and be easier to acquire.
OK- Where do they have to be, by code? I would suggest putting them on the "rear" wall with the slats, just next to the sofa on either side.ohhh. I also forgot..I have 2ft power strips on that go on each wall...The outlets are are code. I can modify to fit those of course. Just letting you know.
Can he rip it both ways, to give you true 3/4 x 4 1/2" dimensioned slats? I'm sure we can find some use for the 1 1/2" off-cuts (they will be a bit less, actually, since the saw kerf takes out a chunk of that, but still around 1 1/4")I did just talk to a guy that said that they would rip 2x6 lumber down to 1x6 for me... its standard doug fir..
If you paint it, make sure to coordinate the color with the fabric backing: IF you have black cloth and white slats, it would resemble a zebra... :shock: - Stuart -I'm tempted to paint the wood so I can keep the room light. I don't want to light stain wood in that volume.
I'd love to see your desk idea. I'm not going with a full blown console, I'll be mixing in the DAW. I will need desk space for a controller. Ultimately, I don't see the point in coloring a signal path with a console unless its high end and I don't see the need really. I like your desk description.
I'm thinking a flat light mocha brown which I did as an accent wall in the LR. I like the idea of an orange peel texture on the boards faces to look like sheet rock, if I'm allowed. I'll do a black fabric behind. It would look much like your screenshot, color wise. I just don't want a wood grain look of that magnitude and I need to keep those walls light! :shock: If things are too dark, it will eventually depress me. :( I'll take as flat as we can without giving up the goods on sound to cap that all off...so, 7-8 inches if you can.
Maybe the soffit would break up the wall features in a helpful way visually speaking... What's your take on how the soffits benefit us acoustically? I still need to picture what all this will look like with the cloud too..could be kinda busy :lol:
The outlets are set to be about 18" from the floor, center of each wall...can't imagine that's going to mess things up too much since that's well below the ear...but who knows?
Seems like we'll probably have me back to building soon either way...I'm optimistic. :shot:
Stuart,
What is your reasoning behind embedding the CR glass so far into the front wall? To maintain a certain resonant frequency within that cavity? I will have about a 2' 8" gap between my windows if I mount the CR side window almost flush with the soffit walls. Seeing your design here makes me question my design. My initial thought was that having the extra big gap would keep the resonant frequency lower, then having the extra wall depth above and below the window would be great for hangers/bass trapping.
Also, assuming your slotted poly is sealed (HH style), typing in the 3/4" x 4.5" slat dimensions with even a 10" depth, to get the HH calculator to reach 118Hz, it needs a slot width as small as an 1/8". When you say that it is effective down to 50 Hz, is that because you will lightly dampen it like you did with the rear treatment device and lower the Q of it? I presume that it would work down an octave, but with a pretty steep slope unless you damped the unit quite heavily. It seems near impossible to find out much information online like this, so I'm sure I can speak on behalf of everyone when I say thanks for sharing your awesome amounts of knowledge!
Greg