The Question
Referred from Recording Website, I received this question
through my "Ask Bob" communication link 10 days ago: |
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Hi Bob, I am close to being done with my studio now and now I
have the foam. I was wondering how you recommend I put it up
for recording drums and other instruments? I glued the foam to
foamboard in 2 ft wide pieces that go from the floor to the
ceiling, so I can move them, put 2 together to make 4 ft wide
pieces, etc. A picture of my studio dimensions are at
[pix inserted below]. If you could also recommend where
I set the drums up for the best sound too, I'd appreciate it.
Thanks. |
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My Response: |
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You have your
"live room" dimensions extremely close to the "Golden Section"
ratio of 1 (high) to 1.55 (wide) to 2.55 (long). Your
length is about 1.5 feet too long, but this probably close
enough. As you probably know, when you get a studio close to
this ratio, any room reverberation will not accent any
particular frequency and you will have a very even tone in the
room. For the best (overall) sounding room you want
about 50% sound absorbing surfaces. The idea of gluing
the absorbing materials to fiberboard in 2 foot widths is an
excellent idea. |
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I see from
another photo (not shown in this article) that you have a drop
ceiling with acoustic panels. This is a good ceiling to
go with. If you haven't done so already, you want a
layer of fiberglass insulation above the ceiling tiles if
possible. This will make the ceiling much more absorbent
to the lowest frequencies. Without this layer the room
will sound like it has a 8 foot ceiling at real low
frequencies and therefore not completely even at the lowest
bass frequencies. |
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Different
Approaches |
There's a
couple of things that I don't know about your studio and how
you intend to use it. Because of this I'm going to give
you a couple of different approaches to choose from,
These "variables" include:
1.
Are you going to have moveable
baffles that you can place around specific musicians,
like behind the drums or behind a vocalist? Panels
similar to what you describe that were 4 feet wide, 6 or
more feet tall and on wheels would do the trick. I
recommend a minimum of 2 sets of two panels that would
be hinged together with a "piano hinge." You physically
restrict the panels so that the "V" can open between 30
degrees and 120 degrees only. If you let the open
fully or collapse fully, they will become unstable and
can topple. You would use these behind the drums
and behind a vocalist or soft solo instrument.
This approach is the most universal and allows you the
most flexibility for different kind of recording
situations (and is the approach I prefer) You are
retaining the ability to make any part of the room have
a small area that is more "dry" (less room reflections) You
can put the two sets of baffles together to form a wider
area in a pattern like this: \__/.
If you adopt this approach, I would evenly place the
panels throughout and over the wall area as shown below.
2, Another approach would be to make different
areas of the room setup for recording different
instruments. Of particular importance is creating
a drum recording area in the room. If you are
going to record several instruments at the same time and
are on a restricted budget, this could be the best
approach.
When you record
drums with other instruments it is important to have
sound absorption behind the set, This cuts down
leakage of the drums into other instruments and annoying
"slap" echoes and leakage of things like cymbals into
mics intended for an isolated drum pickup. The two
biggest problems usually encountered by having the drums
near a reflective surface are a delayed slap from the
kick drum getting into overhead and/or cymbal
microphones and high-hat leakage into the snare
microphone. The reflective surface makes the drum
leakage come from multiple directions, making it
impossible to "point" the microphone to reject the
leakage.
With this setup,
certain areas of the room will be less reflective with
other areas being more reflective and is shown below on
the bottom of of the drawing below. |
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Placement Of Instruments |
Placement of the instruments for recording has a lot to do
with what you are recording at the same time. The drums
would be your starting point.
1.
If you were recording the drums by themselves, or with a bass
guitar that was being picked up with a DI
box, I might place the drums smack dab in
the middle of the room, without any baffling at all. I
would do this, if the room had a good sound and you used the
"approach #1" that I described earlier. The result would
be a lively drum sound that would be real appropriate for rock
or jazz recording. By doing this you eliminate
troublesome sound reflections because they reduce in intensity
because of traveling through air. Air, by the way, is a
natural baffle, especially for higher frequencies. This
is shown in the top half of the drawing below.
2.
If you are recording a band or several instruments together,
you want to arrange the instruments so that musicians are
facing each other and there is sound absorption behind the
drums, and also behind any low-volume instrument to cut down
on leakage. You use the rejection of the microphones to
reduce the direct sound from other instruments and the
baffling prevents loud sound reflections from getting into the
front of the microphones. I would place the drums as
shown in the bottom of the diagram below, even if your sound
absorption behind the drums was from movable baffles. |
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Use Your Ears |
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Advice
from afar, even from experts, never
replaces how the results sound to your ears. If, when
your all done, it sounds bad, move in a different direction.
If it, as I expect, it sounds good to you, you're all set.
Good luck and please let us know how things work out. |
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- Old Bob Dennis |
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