New room with weird shape - setup and acoustical treatment?

[Boris Lau]

Hi all,

I'm moving into a new apartment, with one room dedicated for recording
and mixing. Although it's just for fun and I can't spend a lot of money
an it, I'd like to optimize the sound in that room as good as I can. I'm
recording mostly myself, a lot of DI, plus some percussions and vocals.

The walls, ceiling and the floor are not shared with any neighbours'
apartment, and it's fairly quiet, so noise isolation is not so much of
an issue. The room has kind of a weird shape, please see my drawing:
http://www.borislau.de/base/room.png
It's square, with the ceiling rising from corner (top-right) up to the
dashed line, then it's flat (bottom-left). So the slope of the ceiling
is turned by 45° with respect to the walls.

The floor is covered with a thin carpet that I cannot remove, the
ceiling is made from wood as you can see in this picture, which shows
one corner (top-right) of the room looking up:
http://www.borislau.de/base/room_ceiling.jpg

The walls are plastered washed-out concrete. I know all of this is
probably far from optimal, but it's what I got.

1st question: Nearfield speaker placement (Genelec 8030A, stereo).
Should I align my desk with the wall (left setup) or with the ceiling
(right setup)? Any other suggestions for placement? What distance from
the wall is reasonable?

2nd question: Given your recommended speaker placement, what acoustical
treatment might be necessary? For the left one I thought of corner traps
for the back, plus some absorbers on the sides and the front. How would
that translate to the right setup, if it makes sense at all? Thinking of
my budget I'll probably go for DIY solutions. Can I do without an
absorber above my desk, because of the sloped ceiling?

I know that trying and listening is necessary, and I'll do that. Before
I start to build absorbers, I'll do some measurements as well. But it
would be nice to have a point to start, to limit the space of
possibilities. So I'd be happy for any advice.

Thanks a lot,

Boris

--
http://www.borislau.de - computer science, music, photos

[Boris Lau]

> http://www.borislau.de/base/room.png

Oh, and please feel free to jot into my drawing and send it to my e-mail
adress if you have any suggestions!

Boris



--
http://www.borislau.de - computer science, music, photos

[Ethan Winer]

Boris,

> what acoustical treatment might be necessary?

It's all here:

http://www.ethanwiner.com/acoustics.html

--Ethan

[Boris Lau]

Thanks Ethan, that's a very nice site. So facing a corner is bad because
of the wall-to-wall junction. Facing the wall makes the setup
unsymmetric in that room, since the ceiling is higher at the left side
of the room than on the right, as pointed out in my original post. Any
thoughts regarding this trade-off?

Boris

--
http://www.borislau.de - computer science, music, photos

[Marcello Mastroiani]

Actually, picture 2. seems pretty right to me. You'd get some linear bounces
which diminish in bass as the ceiling goes down. That's what I would do. And
definitely kill the corners with strong absorption. You could also make some
pieces of cloth (tweed) on a wood rectangle (I don't quite know how to
describe it otherwise), like a painter would before painting. And put those
in a more linear pattern under the ceiling to lessen the fall.

It seems like a good idea to put some stronger absorbers on the wall from
the floor to about 1m high, since there is where the bass is going to bounce
off the floor and get on your nerves. :)
Also, a nice tapison on the floor, moquette, as the italian call it, with a
at least 2cm thick layer of hard sponge under it (they sell it in stores
LIKE THAT).

Maybe (make that probably) some will disagree with me, and maybe I've even
wrote something stupid. But on a budget, that's WHAT I WOULD do, and that's
exactly what I will be doing in a week or so. :)

FINNALLY!!!! :)





"Boris Lau" > wrote in message
...
> Thanks Ethan, that's a very nice site. So facing a corner is bad because
> of the wall-to-wall junction. Facing the wall makes the setup unsymmetric
> in that room, since the ceiling is higher at the left side of the room
> than on the right, as pointed out in my original post. Any thoughts
> regarding this trade-off?
>
> Boris
>
> --
> http://www.borislau.de - computer science, music, photos

[Ethan Winer]

Boris,

> So facing a corner is bad because of the wall-to-wall junction.

Actually, facing a corner is bad more because that puts another corner
directly behind you. Corners are sort of like parabolic dish antennas. They
focus the sound at you, which is bad.

> Facing the wall makes the setup unsymmetric in that room, since the
> ceiling is higher at the left side of the room than on the right, as
> pointed out in my original post. Any thoughts regarding this trade-off?

Symmetry is important, but if it's only the ceiling height I'd be less
concerned.

--Ethan

[Boris Lau]

Ethan Winer wrote:
> Actually, facing a corner is bad more because that puts another corner
> directly behind you. Corners are sort of like parabolic dish antennas. They
> focus the sound at you, which is bad.
>
> Symmetry is important, but if it's only the ceiling height I'd be less
> concerned.

Thanks for your reply. I tried both, and I have to admit that I took the
other route, considering the clearer better stereo image that I thought
I had, and space effiency in that small room.

Now to room treatment, I'm thinking about building some broadband
absorbers. I've written a post in the acoustics forum at studiotips:
http://forum.studiotips.com/viewtopic.php?p=37332

If anyone of you finds it more appropriate to discuss it here in the
group as well, I'd be happy to put it in here as well (in compressed form).

Thanks for any help

Boris

--
http://www.borislau.de - computer science, music, photos

[Ethan Winer]

Boris,

> Now to room treatment, I'm thinking about building some broadband
> absorbers. I've written a post in the acoustics forum at studiotips:

You'll get better advice in my Acoustics forum at Musicplayer.com:

http://forums.musicplayer.com/ubbthreads.php/ubb/postlist/Board/24/page/1

If you care to post there we'll be glad to help you out. The Forum FAQ there
is also full of useful advice I'm sure will help you.

--Ethan

[[email protected]]

Boris, that's an interesting problem you've got to deal with. In
your room drawing the right hand drawing with the offset desk
arrangement would be preferable with some slight modifications. It's
an acoustical fact that low end frequencies are harder to manage and
that they build up in the corners of the room (also where the ceiling
meets the walls). I would start there and then look at your high end
frequency troubles.

If it's possible to fill up the corner with low frequency absorbers to
kind of round out the room both literally and figuratively. especially
the corner the would be directly in front of the desk. try not to
have the listening position be in the direct center of the room.
That's where the most standing waves tend to build up.
http://www.studiooutfitters.com helped us out a lot...talk to Ben...

[Boris Lau]

wrote:
> If it's possible to fill up the corner with low frequency absorbers to
> kind of round out the room both literally and figuratively. especially
> the corner the would be directly in front of the desk.

What do you mean? Filling up the corner instead of using the diagonal
absorbers?

Boris



--
http://www.borislau.de - computer science, music, photos