Design of control room for project/home studio asymmetry..

[derpeter]

Did you do the calibration procedure for REW? Are you sure that you kept the mic and speaker in exactly the same position in the room for all of the measurements?

Yes

I will try to find out whats wrong, and hopefully have a correct measurement until Thursday evening

[derpeter]

Hi

I hope you´re doing allright?

I havn´t been able to come back to this site for quite a long time.
I was busy with moving to another house and I also had some concerts with some *** hard music to learn and play....

But now I finally have time to come back to my room design.

Well, everything is, as it was before.

I tried to make a new measurement, here is the file

https://www.dropbox.com/s/ynfl0psqnllww ... rrect.mdat


I tried using my MOTU interface this time, does this look more reasonable?

I will make more measurements these days, I think this time i was a little more away from the wall than last time. ^^

What do you think?




Peter

[Soundman2020]

does this look more reasonable?

Much better, Peter! It is making perfect sense now, and the actual readings match the modal predictions very closely (using Bob Golds' calculator). This is good! I wasn't expecting such a good match, due to the strange shape of the room, but it is good news, as it helps to understand the issues, and what to do about them.

First, I just want to confirm that you currently have no treatment in the room, correct? If you do have something, then what is it, and where is it?

Anyway, the good news is that it looks like the room can be treated to get it sounding a lot better.

First, you have some very early reflections that need to be killed: I'm pretty sure they must be coming off the angled ceiling in front of you, since that is the only thing close enough to cause such short delays (under 1 ms). So put some soft absorption on that angled section, right above and behind the speakers. Probably 5cm thickness 80cm wide would be enough.

Next, you are getting early reflections from something with a path length of about 3.8 m: the only thing that fits that is the side walls, so you also need thick absorption there: put a large thick panel (at least 10cm) spaced 5cm to 10 cm away from the wall, at the first reflection points. Make those panels big: about 1.2m wide and floor to ceiling.

Next, you have early reflections coming of something with a path length of about 7.5m. My guess is the rear wall, so you need thick absorption there too: once again, at least 10 cm, spaced 10 to 15cm away from the wall. That should also be floor to ceiling, and very wide: about 2.4 m would be good. You could also tilt that forwards a bit, so it is further from the wall at the top, and closer at the bottom.

Finally, you have some big modal issues, and the low frequency decay time is too long, s you need lots of bass trapping: Use the rear vertical corners of the room. Build a large superchunk bass trap in each corner, about 90 cm across the front diagonal face, and 60 cm or so along each wall. Also do something similar on the two side walls, above the door and above the window.

Try that, then take another measurement with REW, and post those results here. There should be a decent change, I expect. It probably won't be a huge change, but should certainly be noticeable.


- Stuart -

[derpeter]

First, I just want to confirm that you currently have no treatment in the room, correct? If you do have something, then what is it, and where is it?

I only have my couch and the electric piano in there that you can see on the picture.
I guess they don´t really matter about the lo freq response.
But the piano has to go anyway, so I will put it out and measure again.

So put some soft absorption on that angled section, right above and behind the speakers. Probably 5cm thickness 80cm wide would be enough.

I´m not sure about the "soft" and "hard" absorption people use.
The only product I know in German is Rockwool, but it should do the job, right?

You could also tilt that forwards a bit, so it is further from the wall at the top, and closer at the bottom.

Sounds like a very good idea, I can get deeper frequencies without having to put the couch to far away from the wall

Finally, you have some big modal issues, and the low frequency decay time is too long, s you need lots of bass trapping: Use the rear vertical corners of the room.

I have the door and the window there. Problem for superchunck. Maybe the front corners? The corners behind the speakers? I have lots of free space there for a lot of Rockwool.
And I could probably use the corners over the door and window.
And the horizontal corner at the ceiling from door to window.

What about a Cloud? Would also be nice for putting some light in there.
And some kind of slat resonators? Maybe my room ist too small for them?

Thanks for your fast reply and analysis of the room!


Peter

[Soundman2020]

The only product I know in German is Rockwool, but it should do the job, right?

Rockwool is fine, but see if you can find different types and densities, and also see if you can find fiberglass insulation. I would suggest using a lighter, fluffier type in that angled part, due to the high angle of incidence of the sound waves. There are sure to be different types of insulation. Take a look around a few local large hardware stores / building supply stores, such as Home Depot, or Lowes, or whatever the equivalent is where you live, and see what they have to offer. Note down the density, and your impression of how "fluffy" or "hard" each type is, take some photos, and post the results here so we can help you choose the best type for each area of your room.

I have the door and the window there. Problem for superchunck.

Is there any bare wall at all bet ween the door and the rear wall? Even if you can't make it 45° diagonal, you can still angle it as much as possible and make it as deep as possible: It's a very small room, so it will need lots of bass trapping, and you'll need to use as many corners as you can for that.

The corners behind the speakers? I have lots of free space there for a lot of Rockwool.

Yes! Absolutely! Use those corners too.

And I could probably use the corners over the door and window.

Yes!

And the horizontal corner at the ceiling from door to window.

Yes!

What about a Cloud? Would also be nice for putting some light in there.

I was thinking of a cloud too, and that could be very useful, but do the first round of treatment as above, then test, so we can get a better idea of how to do the cloud.

And some kind of slat resonators? Maybe my room ist too small for them?

They would be great, but you don't have much wall area where you could put them, unfortunately. They would be a good idea for your room, but I can't see any place they can fit in!

- Stuart -

[derpeter]

Is there any bare wall at all bet ween the door and the rear wall? Even if you can't make it 45° diagonal, you can still angle it as much as possible and make it as deep as possible: It's a very small room, so it will need lots of bass trapping, and you'll need to use as many corners as you can for that.

There ist about 16cm. of Wallspace.
If I do that, should I do the opposite corner (next the window) the same way for symmetry, or just go for as much bass trapping as possible?

Or maybe just two panels, one on the door, the other on the wall?

[Soundman2020]

There ist about 16cm. of Wallspace.

That's better than nothing! You could either make a triangular "wedge" in that corner, 16cm deep at the door frame narrowing to 10 cm about 60cm away from the door, or just do a vertical panel 60cm wide and 10cm deep, angled across the corner. The second option would be easier, and probably just as effective.

If I do that, should I do the opposite corner (next the window) the same way for symmetry, or just go for as much bass trapping as possible?

As much as possible. In the rear of the room, and especially for bass trapping, symmetry is not that important. So do the other side as large as you can: for example, about 90 cm across the front face, which means it will be about 60cm along each wall.

Or maybe just two panels, one on the door, the other on the wall?

You might need those as well, but let's wait until you have done the basic treatment and measured the results, then see what else needs doing.


- Stuart -

[derpeter]

Hey Stuart, thanks for your help!

Just one more question now:

If I do 60cm on both rear corners, and 2,4m in the middle of the rear wall I have 3,6 m.
But the wall is only 3,96m long. Maybe I should just do the whole rear wall?
Fake wall out of absorption?

[Soundman2020]

You could do that, yes.

You could even do a "hanger wall", but that might take up too much space (you need at least 50 cm or so for that).

- Stuart -

[derpeter]

Hi!
I went and checked the home depot stores around.
They stopped selling rockwool products and now they only have products from URSA.
It is all cheap glasswool for thermo-insulation. I called the guys at ursa, and it seems it is not very suitable for acoustic purpuses.
They had only one product with measurement data.
Max. thickness is 50 mm and has 0,22 at 125hz. And it was too expensive.


Then I called other manufacturers, and found the following data:

Rockwool Sonorock (3,72€ per m², 100mm thick) density: ca. 28 - 30 kg/m³ flow resistance/friction loss (dont know the english word) > 6
no absorption data

Rockwool fixrock (no prices found) densiy ca. 50 kg/m³, flow resistance > 6
now apsorption data

Isover kontur fsp2-035, (10,42€ m²), density: 45 kg/m³, flow resistance > 5 (guy told me its not measured because its normally for thermo, but he said it is the same material as some other that has flow resistance 15)
They told me it is just like Isover topdeck dp1 wich has apsorption of 0,71 at 125hz

Isover ssp 1/2: (price unknown), density: unknown, flow resistance: >= 11
absorption at 125 hZ (50 mm thic): 0,26


I also found Owens Corning in Germany. Unfortunately they don`t sell mineral wool products in europe...
But the guy told me maybe its possible to import it somehow. But should be very expensive, i guess....

What should I go for? Which density and flow resistance is ideal?

Owens Corning 703 48kg/m³ looks good, but It´s going hard to find a similar product in germany because they normally don´t measure for sound absorption -_-


Maybe rockwool sonorock can do the job?
at least the price seems ok^^

[derpeter]

Will the rockwool sonorock work for my superchunks and panels?
Does anyone have experience with it?

[Soundman2020]

The Sonorock will be fine.

flow resistance/friction loss (dont know the english word) > 6

I'm not sure what they mean there. Gas flow resistivity is measured in Rayls MKS, and the numbers are in five digits for usable acoustic properties. So that cannot be gas flow resistivity, as the number is a few thousand times too small! I guess they must mean something else.



- Stuart -

[derpeter]

Thanks Stuart

Well, the people on the phone (at any of the above mentioned brands) also were not really able to explain what it means^^


I will order Sonorock then

Today I found this:
http://www.bhphotovideo.com/c/product/4 ... eaker.html

Flushmounting kit for Genelecs.
Does it look reasonable?

In this document they provide more info about it:

link to pdf

[Soundman2020]

Does it look reasonable?

Yep! If that's the speaker you have, and that's the way the manufacturer recommends mounting it, then that's the way to do it.


- Stuart -

[derpeter]

I just tried to imagine soffitmounting with sketchup.
Seems like its impossible to do in my room.

Even with a 90° speaker angle it will push my listening position into the middle of the room -_-

Or do you see any way I could make it?

And if I would do it, the nice corners behind my speakers couldn´t work as superchunk/basstraps, right?