ScotcH wrote:When you have time, if you're so inclined, I'd love for you to read over the posts and see if you spot any places I could have improved. Unlikely I will change anything as the room is "done", but I think it would be a great resource for others doing a similar low budget build in an existing space.
Excellent idea, Arek! I really don't want to appear to be criticizing what you did, though, since it looks great and seems to work just fine too. But here's a couple of things I noticed that perhaps could have improved it even more:
1) For insulation between the leaves, you used 1.5" of XPS plus 1" of fiberglass. It probably would have been better to do that with 2.5" of mineral wool. The XPS doesn't have a lot of acoustic absorption properties (absorption depends on "gas flow resistivity", which as the name implies, depends on the material resisting the flow of air through it, within a certain range of useful values). XPS also has very little mass, and it is closed-cell foam, so there's no usable air penetration (completely blocks the flow of air through it, thus its gas flow resistivity is basically infinite), and thus no absorption. But you do have 1" of fiberglass in there, so that's something. It probably also would have been better to sacrifice an extra inch of space in the wall cavity, and get your air gap up to 3.5": The 2.5" you have is a bit low.
Inside-out wall panels going up.
Excellent! Inside-out is, indeed, the best way to do it.
Silencer box. Best effort here with what I have to work with.
Looks pretty good to me!
Was going to do surface mount, but I think this will be sufficient for my needs.
For inside-out walls, you don't really need surface-mount. You can if you want, but it's fine to just have the outlets and switches like you did it, mounted on wood blocks. The important things is to have only one penetration of the leaf, if possible, and it looks like you did that.
The silencer boxes are not touching the joists or the floor above.
{Suprchunkcs}... Just the usual stacked triangles in the corners. 24x24 with a ~33" diagonal across the corner. This is not the cheapest way, but it's the most effective from what I have found, and it's damn simple to build.
Right! It is a simple, fast, and effective method.
The room sounds pretty dead, so I might add more hard surfaces to liven it a bit,
Often, using some type of plastic sheeting over some sections of the insulation will get you some of the high end back again. Different thicknesses of plastic give you different ranges. I suggest testing with REW at each stage in the build to see how things are going, before progressing to the next stage. So in this case, you could have tested before putting the fabric on, then tried a few other tests with different amounts/thicknesses of plastic, until you got the amount of life you wanted.
After some measurements, I rebuilt the front wall. Beefier framing,
Always necessary for speaker soffits!
and tuned the monitors on their side for a wider stereo image.
It probably would have been better to move the speakers physically further apart, rather than rotating them to horizontal. Here's why:
The effect isn't huge, and only covers about an octave either side of the crossover point, but it can be noticeable with some speakers. Best avoided, unless the speakers are specifically designed to be used only horizontally.
it looks as though all of your wall traps are away from the wall at the top but touching at the bottom.
That's not necessarily a bad thing: It means that the panel is not "tuned" to one specific range, but rather covers a broad range. I say "tuned" between quotes, because those are broadband panels, and not really tuned at all! But changing the spacing can affect things a little, and it might or might not be useful.
There is a room mode at 27Hz, and it shows up here ... I probably can't do anything about it, but I can live with it. The other issue ~62Hz I might work on ... it's in the realm of possibility
One phrase: "plane wave base array". Adding a sub (or even better, a pair of subs) along with careful locating of the subs, and careful tuning of their timing, polarity, and EQ, can work magic with low-ens issues in a well treated room like yours. That said, 27Hz is probably nothing to worry about, since there's no musical instruments that go that low anyway, except concert grand piano and the cathedral pipe organ (and maybe canon fire, if you plan to mix the 1812 overture in your room!). Probably not an issue. But even so, you could clean up some of the other issues with subs.
It would be great if you could post the actual MDAT file, for more in-depth analysis. But overall, it looks rather good.
Once again, congrats on a job really well done!
- Stuart -
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But if it measures much better, I might use a "temporary" spacer or brace for when I'm mixing, then just remove it for jam time.
