My long, one-car garage studio, construction phase

[Soundman2020]

I tried that download page, but it started feeding me a stream of spam ads, then wanted me to create an account or something, and I got a warning from my browser, so I just closed the page. So I can't download it from there. Sorry! I'd suggest you try hosting it in a more friendly environment!

- Stuart -

[Bigsby]

Oops! Sorry about that! Let's see if this Dropbox link works:

https://www.dropbox.com/s/9smhvke6nhiy9 ... %20II.mdat

Thanks....

[Soundman2020]

Yup! That works much better! Thanks.

Downloading now....

I'll take a look at it a bit later, and let you know.


Stuart

[Soundman2020]

Sorry about the delay!

OK, the data looks fine now, and all seems to be in order. This is still the untreated room, right? Nothing in there yet except bare walls? I sure hope so....

- Stuart -

[Bigsby]

Yes, still untreated; let's hope it gets a lot better!!

[Soundman2020]

Right! Because what I'm seeing on the REW results is not very pretty right now!

OK, first and foremost: the data is valid, and that's great, but you need to measure the location where you have the mic for that test very, very carefully, in all three directions, so you can always get the mic back there for each new test, after you add treatment. Keep careful note of that mic position; it must go back to the precise position every time, accurate to within a couple of mm, max.

So, do you have a treatment plan?


- Stuart -

[Bigsby]

Hi again--

Yes, Stuart, I have a treatment plan, at least for the absorption part of the plan. I was hoping to determine slat sizes and gaps for the side wall resonators a little further down the REW testing road.

new cr treatment plan.jpg

Does this look OK for starters? My thought was to complete the hangers and insulation inside the soffits, re-assemble them, and then test again. Does that sound like a good idea, or should I just do all the absorption in the room (except for the cloud) before testing again?

Thank you!!

Mark

[Soundman2020]

It's always a god idea to test the room again after each round of treatment goes in, to see what it did and what still needs to be done. It just takes a few minutes to do each test. So I would suggest testing after you do the soffits (there will be some change, but not huge), the again after the superchunks go in (that should show big changes!), then again after the cloud is in (more big changes), etc. That record of how the room is progressing can really help you decide on the final treatment.

- Stuart -

[Bigsby]

Hello All--

I've been away for a bit, but I'm now working on the treatment for my soffits. I have what I hope is a quick question. My soffits are quite small, and I'm wondering about my plan to have hangers beneath the speakers. My plan all along has been to do what most everyone on this site does when they built soffits, and have hangers in the cavity below the speakers with loose insulation all around the speaker boxes along with a channel of some kind (made of chicken wire or ducting, etc) in the upper area where the loose insulation is to ensure unobstructed airflow.

new cr treatment plan.jpg

I would probably do a duct something like this, an image I "stole" from Simone's beautiful build thread:

Simo%20speaker%20case%201.jpg

However, when I look at my lower cavity....

Cavity under speaker 1.jpg

It seems to me I could only fit three hangers in there, and small ones at that. My biggest hanger would probably be 7" x 30" with two smaller ones flanking it that would be 4" x 30."

So my question is this: Would it be more effective treatment-wise to approach the cavity below the speakers in the same way as the cavity above? In other words, what if I installed an airflow duct below the speaker plane that would start in the open space near the floor, and then attach that to the bottom of the speaker shelf? I would then fill the lower cavity with loose insulation in the same way as the upper cavity. Or am I better off just going with the typical hanger approach, despite the fact that they would be so small?

As a reminder, my monitors are Adam A7X's.

As always, thank you!!

Mark

[Bigsby]

Well, I decided to go ahead and do hangers for my soffits below the speaker plane. The final dimensions of the hangers were 7" x 25" for the center hanger and 4" x 25" for the hangers that flank the center hanger. The hangers are roughly 3 1/2" thick, which was about as thick as I could make them while still being able to fit three in each soffit.
Here's what the hangers looked like before installation:

All hangers.jpg

I used zip ties to fasten them to the cross members that they hang from. These worked great for adjusting the vertical placement precisely.
Here's what they look like installed in the left soffit:

hangers left soffit.jpg

...and the right soffit:

hangers right soffit.jpg

....and here's a closeup of the left side:

hangers closeup.jpg

I hope this looks OK--they are obviously quite small, but I know there's a good reason everyone does it this way, and I'm not about to reinvent the wheel.

I'm about to permanently install the speaker shelves and the speaker boxes. I will then pile loose insulation around the boxes with a channel for ventilation. FInally, I will glue and screw the lower layer (3/4" particle board) of my bezel. This is kind of the point of no return for the soffits, so if anyone has any criticisms about how things are looking, please tell me soon!!!

Thanks,
Mark

[Bigsby]

Sorry to do this, but I'm at a bit of a standstill so.....bump?......

[Soundman2020]

Looks like they should work fine. Did you check that they do not touch the sides, back or bottom of the cavity? Can they swing freely? If you nudge one of them a little bit, and allow it to swing, do the other two start swinging a little bit as well, in sympathy?

- Stuart -

[Bigsby]

Ok--time for a soffit update. I went ahead and closed up the soffits, so hopefully they look ok!!

Did you check that they do not touch the sides, back or bottom of the cavity? Can they swing freely? If you nudge one of them a little bit, and allow it to swing, do the other two start swinging a little bit as well, in sympathy?

I did make sure that all the hangers swing freely; they do not touch each other or any of the sides or bottom of the cavity. However, when I swing the center hanger, the movement on the hangers on either side is very slight, almost imperceptible. When I swing one of the smaller hangers on either side, I don't see any movement in the other hangers. I suspect this is because they are so small? If this is unacceptable, or if it means that the hangers won't do any good, I could at least stuff some fluffy insulation in there, and use the hangers to maintain an air channel of sorts for the speaker ventilation. Let me know what you think on that. Unfortunately, I'm past the point of being able to change the hangers, because the soffits are assembled, as follows:

First, I finished the framing, gluing and screwing as I went:

Left Soffit Framing.jpg

Right Soffit framing.jpg

Right soffit framing closeup.jpg

...Then I built my ventilation channels out of chicken wire:

Left soffit chicken wire.jpg

...then I wrapped those channels with plastic sheeting, with an opening where the vent hole will be in the bezel, to try to keep any insulation fibers from falling into my speaker boxes:

Right soffit chicken wire with plastic cover.jpg

I used zip ties to secure the chicken wire to the vent opening:

Vent detail.jpg

Then I loosely stuffed rockwool scraps around the speaker boxes:

left soffit stuffing.jpg

Here's what they looked like before being covered up:

left insulation done.jpg

right insulation done.jpg

Here's what it looks like with the "sub-bezel" installed (glued and screwed). There will be a finish layer of birch plywood over this that will follow the contours of the face of the Adam A7X.

Left sub-bezel.jpg

right with speaker.jpg

I ran tests with treatments in place, which you can get here:
https://www.dropbox.com/s/j3e0egunnjb7a ... ments.mdat
...and I have to admit that I'm pretty ignorant about REW, but I'm assuming that things still don't look good.

More to follow......

[Bigsby]

Just as a reminder, here is my treatment plan. I'm thinking of Roxul Soundstop in the stud bays, sandwiching the fluffy insulation which will be stacked in the triangular spaces in between. My super chunks aren't that "super"--the ones in the back of the room are 19" deep; the one on the left side of the room is about 13" deep, including the framing.

new cr treatment plan.jpg

I'm planning to do all of it with the exception of the cloud and then test again. Question: I remember seeing a very helpful table with different insulation products and their air flow resistivity. I should have bookmarked it, but I didn't. Does anyone have a link for that? I just want to be sure I do the best job possible with my remaining treatments.

Anxiously awaiting feedback.....Thank you!!
Mark

[Soundman2020]

I did make sure that all the hangers swing freely; they do not touch each other or any of the sides or bottom of the cavity. However, when I swing the center hanger, the movement on the hangers on either side is very slight, almost imperceptible.

That's fine. They aren't very big, so the effect won't be very big, but as long as you see something then it shows that they are freely hanging, and somewhat in sympathetic movement.

...and I have to admit that I'm pretty ignorant about REW, but I'm assuming that things still don't look good

Well.... they ain't beautiful yet, but they sure are a lot less ugly than before! A couple of samples:

The waterfall plot for your left speaker, the way it was originally (baseline):

bigsby-baseline-waterfall-l.png

And the way it looks now:

bigsby-soffit-partial-waterfall-l.png

Then your baseline RT60 graph for both speakers:

bigsby-baseline-rt60-both.png

And the way that looks now:

bigsby-soffit-partial--rt60-both.png

So yeah, I'd say that's a pretty promising improvement!

How do you have the controls set on the rear of your speakers?

- Stuart -