Figuring out the acoustics for a new room

[Jarkko Mattheiszen]

Me and the fiancé finally found a new apartment, so that means my mixing room will be moving 250km, too. I've been playing around in Sketchup to figure out the most cost effective way to treat the new room, and here's what I got so far:

The room is 395cm deep, 305cm wide and 270cm high. It's a very small room, quite a bit smaller than the one I'm in now, but it's gotta do for a while, and I've seen people transforming such rooms into pretty decent mixing rooms before. The early reflection points and the front wall are 3cm thick Ecophon acoustic panels and the back corners are 10cm thick fiberglass panels, because I already have those available and they work pretty well. The front corners will be superchunks, covered in a very thin layer of plastic for practical reasons, and the panel in front of them is just normal fabric stapled to the wood frames. The white thingy at the lower left is a fixed wardrobe that unfortunately can't be removed, but I can remove the doors and use the two rightmost closets as ghetto diffusors while placing the bass trap panels inside the leftmost closet, so it's not a biggie. I'll pick up some nice and thick fabric for the curtains to minimize the effect of the window. I will also probably hang another Ecophon panel as a cloud.

Have you guys got any better ideas for this? I will not be making any sort of permanent changes to the room as it's rented and I had a hell of a time covering up my shenanigans in this apartment

Thanks!

 

[jipchen]

The thin plastic layer is no good idea because it fucks up the high-freq area , just use ripple protection, that's actually made for this purpose (to prevent mineral wool from traveling through your room )
The acoustician who planned my studio also always stressed the importance of deep enough absorbers (at least 14 cm's).
Obviously 10 is not that far away, but double-mounting the mineral wool panels would be neither expensive nor too much work, no?
What he also always told me was the importance of treating the ceiling but it looks like you thought of that, too.
Measuring the room after you're done with what you planned so far will most probably help a lot to find the problem zones.

 

[Jarkko Mattheiszen]

The thin plastic layer is no good idea because it fucks up the high-freq area , just use ripple protection, that's actually made for this purpose (to prevent mineral wool from traveling through your room )
The acoustician who planned my studio also always stressed the importance of deep enough absorbers (at least 14 cm's).
Obviously 10 is not that far away, but double-mounting the mineral wool panels would be neither expensive nor too much work, no?
What he also always told me was the importance of treating the ceiling but it looks like you thought of that, too.
Measuring the room after you're done with what you planned so far will most probably help a lot to find the problem zones.

Hey, thanks for the input! I'm not familiar with ripple protection though I've probably seen it (heck, odds are I've used it ) due to working at a construction company, mind posting a pic? I'm not all that worried about the high frequency effect, though, as the plastic I thought of using is identical to the extremely thin garbage bag plastic and it wont be exposed but covered in fabric with an air gap in between. The effects should be pretty minimal, especially since it's only in the front corners. One thing I also want to take into consideration here is mobility. This way I could build the superchunks from smaller elements that are stacked up, so I can easily remove them and take them to the next place when needed. I'll look into that, though! Dual mounting the rear panels is a good idea, and I could probably easily use the left-over wool panels to do that at least partially for the time being.

 

[jipchen]

Hey, thanks for the input! I'm not familiar with ripple protection though I've probably seen it (heck, odds are I've used it ) due to working at a construction company, mind posting a pic? I'm not all that worried about the high frequency effect, though, as the plastic I thought of using is identical to the extremely thin garbage bag plastic and it wont be exposed but covered in fabric with an air gap in between. The effects should be pretty minimal, especially since it's only in the front corners. One thing I also want to take into consideration here is mobility. This way I could build the superchunks from smaller elements that are stacked up, so I can easily remove them and take them to the next place when needed. I'll look into that, though! Dual mounting the rear panels is a good idea, and I could probably easily use the left-over wool panels to do that at least partially for the time being.

I've used this stuff, it's called "pro clima RB". There's a different material, a lot cheaper that's called pro clima RS but it's out of paper and not cloth so I think it's not really ideal to take that.. plus it will probably rip real easy.
The RB stuff is the black cloth in the construction pictures I posted. If you strech it over the wooden frame it's also transportable.
I understood where you wanted to use the plastic, because I had the same idea and the acoustician said it was really baaad, mkay The thinner, the lesser it matters of course - but he insisted on not using plastic (also in his forum). Can't really tell how much it really affects the highs, just forwarding what he told me.

Sorry I am not really able to help because allthough I tried to read up on the acoustics subject, I gave up after a few days
Hope everything works out for you (also the whole moving - which I HATE, heh)

 

[Jarkko Mattheiszen]

I've used this stuff, it's called "pro clima RB". There's a different material, a lot cheaper that's called pro clima RS but it's out of paper and not cloth so I think it's not really ideal to take that.. plus it will probably rip real easy.
The RB stuff is the black cloth in the construction pictures I posted. If you strech it over the wooden frame it's also transportable.
I understood where you wanted to use the plastic, because I had the same idea and the acoustician said it was really baaad, mkay The thinner, the lesser it matters of course - but he insisted on not using plastic (also in his forum). Can't really tell how much it really affects the highs, just forwarding what he told me.

Ah, yeah, we've used the paper version a lot. It does rip fairly easily :/ I think I might as well try out both ways if needed, since if I try out the original idea first and find it problematic I can really easily just open the chunk's front surface up and replace it with the RB stuff or the other way around

Part of the difficulty in figuring out how to treat rooms is that there are so many schools of thought in acoustic design. Somehow it always feels like a compromise one way or another

Sorry I am not really able to help because allthough I tried to read up on the acoustics subject, I gave up after a few days
Hope everything works out for you (also the whole moving - which I HATE, heh)

Your input is much appreciated and thanks! Moving is a huge pain in the ass, especially when you have stuff like guitars and other gear that doesn't really enjoy being in the back of a truck for too long. As well as stuff like three sofas. How the fuck did we even end up with three sofas in the first place?

 

[Vinny]

OT... But what program did you use for the renderings?

 

[Jarkko Mattheiszen]

OT... But what program did you use for the renderings?

Google Sketchup

 

[John_C]

Having plastic over an absorber will decrease high frequency absorption. It's always tempting to go for maximum absorption across all frequencies, but with a small room you may find you have *too much* high frequency absorption. Worth thinking about. I would recommend buying "the master handbook of acoustics" for a thorough but accessible text on acoustic design and treatment

 

[Jarkko Mattheiszen]

Having plastic over an absorber will decrease high frequency absorption. It's always tempting to go for maximum absorption across all frequencies, but with the amount of treatment you're using you may find you have *too much* high frequency absorption. Worth thinking about. I would recommend buying "the master handbook of acoustics" for a thorough but accessible text on acoustic design and treatment

Yeah, that was one thing I was a bit concerned about. The Ecophon panels are great for reducing high frequency flutter, so minimal reflections from the thin plastic in the front corners might turn out to be a positive thing. I'm not aiming for a completely, utterly dead room which would naturally require a lot more treatment, anyway. I'm not under the illusion of turning it into a perfect control room, either, as this will be a temporary work spot for an indefinite period, so my main concerns are reducing the low frequency anomalies and the nasty flutter effects which are always present in such small rooms. Once I finally find a real place and once it's financially possible and profitable, I will naturally hire an acustician to do all the designing, but this room I want to be just a decent enough environment for me to work on mixing projects.

 

[vespiz]

Can you put those side panels up with a gap behind them? It lowers the effect by an octave if the gap is equal to the thickness of the panel.
Also, I'd skip the Echophone panels as a cloud, unless you get them cheap (ie. for free). I'd save the money and do a DIY cloud. It really isn't that difficult.

And remember the wall/ceiling corners, a good place for some traps as well..

Check it: http://www.facebook.com/home.php#!/album.php?aid=21375&id=706851491
And: http://www.facebook.com/album.php?aid=21375&id=706851491#!/album.php?aid=172301&id=706851491

 

[Jarkko Mattheiszen]

Can you put those side panels up with a gap behind them? It lowers the effect by an octave if the gap is equal to the thickness of the panel.
Also, I'd skip the Echophone panels as a cloud, unless you get them cheap (ie. for free). I'd save the money and do a DIY cloud. It really isn't that difficult.

And remember the wall/ceiling corners, a good place for some traps as well..

Check it: http://www.facebook.com/home.php#!/album.php?aid=21375&id=706851491
And: http://www.facebook.com/album.php?aid=21375&id=706851491#!/album.php?aid=172301&id=706851491

Hmm, FB tells me "The content is currently available", I'll check it out later though! Yeah, the Ecophone stuff, while pretty efficient, is HUGELY overpriced, but fortunately I've already got the panels. They were left-overs from a construction site I worked at, so I got them for free

I was thinking of keeping the panels at the wall from one side and lifting them away from the wall by 3cm from one side, which should maximize the dampening range, correct?

 

[jipchen]

To absorb a certain frequency (or at least boosting the absorber-effect in a certain range) the distance of the absorber to the wall should be λ/4 (1/4 wavelength of the frequency you wish to absorb).
You can easily calculate the room modes with the room modes calculator and see if and with what distance exactly you can arrange your absorber units to improve the "bad" frequencies. In my studio, all absorbing elements are 10cm from the wall.
Your idea sounds reasonable to me, at least in theory.. on the other hand the room should normally be symmetric.

An easy way to build a transportable absorber with built-in-distance to walls is building a (wide) frame, and then placing the mineralwool plate (works only with "plates" of course) on top of it, not into the frame. Then you cover the whole thing with fabric and staple it on the inside of the wooden frame.

 

[Jarkko Mattheiszen]

To absorb a certain frequency (or at least boosting the absorber-effect in a certain range) the distance of the absorber to the wall should be λ/4 (1/4 wavelength of the frequency you wish to absorb).
You can easily calculate the room modes with the room modes calculator and see if and with what distance exactly you can arrange your absorber units to improve the "bad" frequencies. In my studio, all absorbing elements are 10cm from the wall.
Your idea sounds reasonable to me, at least in theory.. on the other hand the room should normally be symmetric.

An easy way to build a transportable absorber with built-in-distance to walls is building a (wide) frame, and then placing the mineralwool plate (works only with "plates" of course) on top of it, not into the frame. Then you cover the whole thing with fabric and staple it on the inside of the wooden frame.

Ah, I was a bit unclear. I meant lifting each absorber from one side, leaving the other side of the absorber against the wall. So the room would be symmetrical

 

[John_C]

a very nice room mode calculator http://www.hunecke.de/en/calculators/room-eigenmodes.html