Here is the trim I was planning on doing around the baffles. Need to make sure it won't cause any issues.
Looks like it should be OK, but do round the edges that face towards the speaker itself: Sharp edges are sources of edge diffraction. OK, yes, that trim is a long way off from the acoustic center, and out at 90° off axis, so there's not much going on there at mids and highs, you'd think, but there's still something, and there's always reflections and the diffuse field to deal with. I think I've mentioned this before, but if you can do ten things in your studio that each make a difference of 0.5 dB, then you made a difference of 5 dB!
So that's fine, just round the edges. Get out your trusty, reliable, accurate, stable router!
(For those following this thread that didn't hear about it, Frank's router played a nasty trick on him, and nearly trashed one of his speaker baffles...)
That's what I'm asking about. I can't get rigid insulation till Tuesday next week. Wanting to know if it has to be rigid, cause I'll have to wait till then to do the final assembly. Sorry if I'm getting on your nerves, but I need to know.
I've been in bed with the flu the entire weekend since Friday, thus not very responsive. This insulation is fairly important, as these two slot walls are aimed at fairly low frequencies, so we need stuff that has high coefficients of absorption in the low-mid and low frequency range. 701 and 703 do. So do some others, but it's hard to say for sure if what you have is the right stuff without knowing what the exact acoustic characteristics are. If you have a link to the acoustic specs page for the product you have on hand, and it shows numbers around 0.5 or higher at 125 Hz, then you should be OK. I show 3" in the model, but if you need to go 3.5" to get that, then that's fine too.
Here's some that do:
- Owens Corning: Sound Attenuation Batts, OC-701, OC-703
- Roxul: RXL 40, RXL 60, RXL 80, Safe'n'Sound, AFB, RHT-40, RHT-60,
- CertainTeed: OEM 600
- Fibrex: FBX 1240, FBX 1260, FBX 1280
- Rockwool: RW-5 (Although that's a bit heavy)
Etc.
Any of those would be fine, in either 3" or 3.5" if needed.
Also, can you give me a heads up on any special insulation I'm going to need for the rest of the project? All we have left is the cloud and the wall under the window after the slats I think. getting special insulation takes a few hours round trip and I'd like to make it just one if need be.
Not sure yet. For the cloud, you'll need about 50 ft2 of 3". Perhaps something similar to the above, but I'm thinking of going with an FRK or FSK: Johns Mansville IS 600 FSK would be great, if you can get it! It only comes in 2", I think, but we could put 2" of that with the FSK side down (facing the room) and an inch of something else above it (701, pink fluffy, etc). Ottawa Fiber OFI-48 FSK would also be good, but also comes only in 2". The best: 3" OC-705 FRK would be excellent. All of those have good absorption in the low end, but less in the mids and highs, due to the facing, which is exactly what we want up there. We'll use a thicker fabric (or maybe thin carpet) just under your finish fabric, to take the edge off the very high end, which is still a bit bright in your room as compared to the low mids, but the cloud is mostly going to do some more for the low end, as well as deal with some reflections.
So look around and see what you can find in FRK or FSK faced insulation locally, and let me know so I can decide on that.
For the part under the front window, between the soffits: that's not too important: we can use whatever is left over from other treatment. We'll only do that after we get your sub in its final location, and tuned, as that's roughly where the sub will be, and we'll need to damp that space one the sub is in. And for the part above the window: that's my final "wildcard"! Not sure what's going in there yet. It might need something, but I really can't say yet until we get to the REW tests at that point. In the model, I put in a nondescript absorber panel as a place-holder, and it might turn out to be something like that, but it might be different. That's the last bit of bare wall space left over, so that's what will o the final tweaking, if it is able to do that.... we'll see!
OK, here's the thing: after the CR is done, there's still the re-tuning of the LR, so you'll need some more insulation for that. You might as well buy a bit extra of everything now, so you have it on hand for the LR.
One thing I should mention: the CR is in the final stages of acoustic tuning, so the things you do now are not going to have major, mind-blowing effects on the acoustic response. This is just tweaking. The could will have a nice effect, yes, and the desk will have a not-so-nice effect (it always does...) but the slot walls above the sliding doors, the space below the front window, and he space above the front window are not going to make huge differences. I just wanted to warn you about that, so you don't get disappointment when the lines don't all go dead flat after you d a lot of work carefully cutting and placing slats with millimetric precision...
- Stuart -
