16 May
2006
16 May
'06
7:52 p.m.
From: Carlo Capocasa <capocasa(a)gmx.net>
Subject: [linux-audio-user] Samson C01U USB Mic Low Noise HowTo
To: linux-audio-user(a)music.columbia.edu
Message-ID: <e4dgks$tbu$1(a)sea.gmane.org>
Content-Type: text/plain; charset=ISO-8859-15
What's up, all!
Just treated myself to my first condensor microphone, a USB-powered
specimen of fiendishly convenient technology that includes a pre-amp and
d/a converter. For entry-level it probably doesn't come any better than
this.
I have heard reports that this device was noisy, however I was able to
fix that:
I might have been one of the people saying it was noisy.
I don't know if you saw the post I sent here about it, but I was
completely wrong about it having a fixed gain and using a digital gain
control after the a/d. There was a web page about it with some messages
from samson techs, but I cannot find the url now.
It uses a little stereo a/d chip with built in preamps and feeds the
output of one side back into the other to get more gain.
So.. the output is actually stereo, with the right side being quieter
than the left as it's only gone through one stage of amplification.
One amusing thing to try is this....
Use alsamixer and set the input gain so the right side is 100 and the
left 60.
Route each side to it's own track in ardour.
Sing into it a bit. Both inputs should show the same level.
Record a bit.
The right one has a tiny bit less background hiss and is a tiny bit
cleaner as it's only been through one gain stage. It's also out of phase
for some reason.
The difference is much too small to be worth the bother, but I thought
it was kinda interesting. Perhaps there are some other hacks to be found
by combining both gains/sides.....
1. Set the device pre-amp to 75% volume in ALSA mixer.
2. Sing with your mouth right before the grate above the Samson logo.
The device is calibrated to be relatively distortion-free when singing
moderately loud, and this way you will have enough signal to be very
happy with the noise level.
3. Pop-effects are disturbing singing this way; the manual recommends
the famous engineer's trick of stretching a bit of nylon stocking over a
hoop and singing through that. I now have the privilege of asking a girl
I know for used stocking to provide some extra suggestive edge to my
kinky songs while doing something technically beneficial. Life is good.
Rock n roll!
By the way, have you managed to get it working at less than 512
frames/period latency? It refuses to let jack connect on my computer
when I try it at 256.
Carlo