CR Treatment and Tuning---The home stretch!!

[Soundman2020]

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 -

[Stadank0]

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. 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...

[diedushka]

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.

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?

[Soundman2020]

What details do you need except for dimensions, framing, wall and ceiling construction to be able to provide professional advice on acoustic treatment?

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 -

[Soundman2020]

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.

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...

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...

OK, no soffit! No problem. Just floor to ceiling slats:

Frank--CA--USA-V11-S181-CL--SKP-2017--S364--slotted-poly-sidewalls-01.jpg

Frank--CA--USA-V11-S181-CL--SKP-2017--S364--slotted-poly-sidewalls-02.jpg

Frank--CA--USA-V11-S181-CL--SKP-2017--S364--slotted-poly-sidewalls-03.jpg

Frank--CA--USA-V11-S181-CL--SKP-2017--S364--slotted-poly-sidewalls-04.jpg

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 -

[Stadank0]

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. 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.

[Stadank0]

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.

[Soundman2020]

I don't find it to be ugly..

its mostly the feeling of space I care about.

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.

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?

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...

Not my week, I just gotta speeding ticket to boot which wiped out my uber earnings for the week.

Well gee, that wasn't such a good idea! Painful....

The money is always going somewhere I tells ya!

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!

Any ideas how I might be able to work with space for outboard gear? Probably a desk integration at this point...

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.

can we make the boards 8' instead of ceiling to floor? It would help the cost tremendously and be easier to acquire.

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.

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.

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.

I did just talk to a guy that said that they would rip 2x6 lumber down to 1x6 for me... its standard doug fir..

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'm tempted to paint the wood so I can keep the room light. I don't want to light stain wood in that volume.

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...


- Stuart -

[Stadank0]

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! 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

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.

[Gregwor]

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

[Soundman2020]

What is your reasoning behind embedding the CR glass so far into the front wall? To maintain a certain resonant frequency within that cavity?

Mostly room volume. Recommended minimum volume for a critical listening room is 1400 cubic feet. Frank's room is 1380 cubic feet, which is fine but on the edge. If I would have brought the window in to line up with the soffit faces, I would have lost another 60 ft3 or so, which I did not want to do. That's over 4% of the room volume. For small rooms, interior volume generally takes priority over modal issues.

Also, having the window in a different plane does help a little with both modal issues and SBIR, to a certain extent. In a small room with an unusual layout ("corner control room"), I'll take every bit of help I can get! I used a lot of "tricks" to maximize the volume and acoustics of this room. Originally Frank wanted the largest possible size for his live room, with the control room as second priority, so I designed the entire studio like that (even the bathroom has a strange trapezoidal shape to eak out a few more square feet from the LR). But I didn't want to compromise too much on the CR, so I kept it as big as possible, within the limitations. I tried not to waste even a single cubic foot!

There's one more reason here too: by pushing the window deeper, Frank gets slightly better sight lines into the LR, since the window frame is a little wider, as it is not restricted by the soffit faces. In the years since I originally designed Franks room I have come up with an even better method for improving sight lines (sorry Frank! I only thought of it after I designed your place), but I'd prefer to keep that to myself for now...

I will have about a 2' 8" gap between my windows if I mount the CR side window almost flush with the soffit walls.

That's a pretty large gap, which tells me that you are probably wasting space there. It's great for very good isolation down to low frequencies, of course, but that only really matters if the rest of the wall has the same gap and mass.

Also, assuming your slotted poly is sealed (HH style), typing in the 3/4" x 4.5" slat dimensions with even a 10" depth,

It sticks out 9" from the stud faces, but these are inside-out walls, so there's actually 13.5" of depth.

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?

Exactly. The coefficient of absorption will still be above 0.5 at 50 Hz, which is usable. Here's the predicted tuning for the two most critical elements:

Frank--Predicted-acoustic-response-of-curved-slotted-poly-side-wall-05.jpg

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!

Yep! Many designers don't like sharing too many secrets (me included!), but tuning a slot wall isn't that much of a secret. The problem isn't in the prediction equations so much as in the practical implementation. That's where the important information is lacking in many of the DIY explanations and YouTube videos.... and curiously, those videos and websites don't seem to show actual acoustic test results from the advice they give! I wonder why? Unlike John's forum, where we really do want to help.

- Stuart -

[Soundman2020]

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.

It's the Sterling E series desk that I'm thinking of as the concept. Here's the actual desk inserted in your room:

Frank--S364--Sterling-desk-concept-01.jpg

Frank--S364--Sterling-desk-concept-02.jpg

Frank--S364--Sterling-desk-concept-03.jpg

It's a little large (front to back) for your room, but I was thinking of taking that same concept and re-working it to fit better, in something you can build yourself (buying that thing new costs a fortune: quite a bit more than your speeding fine! )

Let me know if you like it, and I can add that to the "to do" list, for future stuff.

I'm also going to modify the soffits a bit more, to improve the angles and dimensions for your new speakers. More on that later... (another "to do" item....)

- Stuart -

[Soundman2020]

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

I'll do a rough mock-up when I have a chance. I'm on vacation this week and next, and also working on another urgent project that has been delayed too much.... I'd like to get you the curve ASAP, so you can at least start cutting out the spacers and buying materials.... stay tuned....

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?

Pity they have to go on the side walls.... Putting them on the rear would have been a piece of cake. But no problem: I'll fit them in for you.

- Stuart -

[Stadank0]

Yeah,

I definitely want to build my own desk. Furniture is insanely expensive!!! That desk is $4000 US at Sweetwater! I could never ..Too many other things worth saving up for, like the gear to go in the desk


I new I was going to do some sort of desk rack space..Interested to see how much space I can pull off. Just wanted to see if you had some crazy option I hadn't thought of. I will be doing modular 500 series type stuff for sure..If I actually make money at this then I'll look at higher end converters like Dangerous or Burl, but the cart is way in front of the horse there.

Sooo, put that on the list..

[Stadank0]

I'm on vacation this week and next, and also working on another urgent project that has been delayed too much.... I'd like to get you the curve ASAP, so you can at least start cutting out the spacers and buying materials.... stay tuned....

Are we set back quite a bit on time? I know you have other stuff going on in March. Not freaking out...just a bit of a surprise....If possible, I'd like to get a general time frame for getting to the point physical room treatment completion. Walls, soffits, cloud...Everything up to digital.

Naturally I want to get done as soon as possible after 3.5 years, but I also want to be reasonable and realistic. I'm ready to work day and night on my end, so it really just depends on what your able to do...