Re: [linux-audio-user] Live recording : Post production/ removing noise

From: Spencer Russell <slothlove@email-addr-hidden>
Date: Fri Aug 25 2006 - 18:41:12 EEST

When I was a student at Oberlin I worked for the audio department of
the Conservatory, so I recorded somewhere around 100-150 classical
recitals a year, almost all with a stereo pair.

I used a whole lot of small diaphragm condensers in an ORTF setup
(cardioid mics with 110 degrees between and the capsules 17cm apart).
I'm a big fan of the Neumann KM184 mics. I also used the Sennheiser
MKH140 mics sometimes, and shoeps CMC cardioids.

I didn't worry too much about the music getting mixed down to mono,
which is why I didn't use an XY configuration very much. Generally I
prefer near-coincident (the mic capsules a little apart, as in ORTF)
to coincident(The capsules right on top of one another, as in an XY
setup) because it captures delay as well as amplitude information and
gives a stereo field that I like better.

I less commonly used a spaced pair of omni mics, which in my
understanding capture the stereo field mostly with delay info.
(Sources on the left hit the microphone on the left a little before
they hit the right mic) I like a spaced pair for a large ensemble, and
for a really big group sometimes I'd use 3 mics evenly spaced, or even
an ORTF flanked by omnis. We had a couple pairs of Neumann M150 mics
which are absolutely wonderful. You do need to pay attention to where
you point them though, because they get more directional at high
frequencies. I also used Sennheiser MKH20 mics for less critical

With all of these stereo pair techniques, I pan the left mic hard left
and the right mic hard right, or more commonly, I'm just recording
each mic directly to the left and right channels of a DAT with a CD
backup. Also, it's important to be flexible, probably 85% of the time
I basically just set up a pair of mics in the center of the room about
10-15 feet in front of the performer (for an individual or small
ensemble. Back it up a bit for larger groups) with one of the
techniques described above. It wasn't unheard of though, to vary
wildly from the standard 2-mics-in-the-middle approach, so if you have
time for a sound check, it's nice to be able to move the mics around
and let your ears decide. Depending on your clientelle that can be a
rare luxury, though, so get used to figuring out why a room sounds the
way it does so you know where to put your mics.

As far as fixing noisy recordings, there's only so much turd-polishing
you can do, but I've had some success with the Gnome Wave Cleaner.
You've got to be pretty careful though, because if you use it too
aggressively it makes things sound really nasty. Watch out for a kind
of metallic comb-filtery kind of effect.

hope this helps,

On 8/25/06, ish@email-addr-hidden <ish@email-addr-hidden> wrote:
> hi All ...
> i had recorded a classical guitar concert using a DAT player and a couple
> of Dynamic mics (Shure 606). To get stereo recording... now the concert
> hall where i did this recording was an old one with very noisy/creeky
> chairs. I really wanted to remove all this from the recording along with
> all the coughs and the faint A/c hum. Can anyone please recommend a
> procedure i can use to remove these unwanted noise without damaging the
> recording.. and what is the right procedure to record classical or Acoustic
> recitals ie what mics should one use with that and at what settings etc
> ..thanks
> Best
> ISh
> (
Received on Fri Aug 25 20:15:05 2006

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