From: ajf <ajf_at_midmaine.com>
Date: Fri, 07 Nov 2003 09:58:09 -0500

Nathan Gray writes:

> What kind of microphones work with the line in? Do they have to be
> powered? (My pc microphone didn't do anything).
> and

The FAQ on the Rockbox web page contains a good section on mics. It is a
great place to start.
Archos sells a powered stereo electret mic on their website. A number of
Rockbox users have reported success with it.

The nice thing about good electrets is that they have a flat frequency
response across the whole audible range, they are small, light
and they are cheap at least relative to traditional professional quality
mics. Pros will sneer at them, but for portable or field recording, they
can't be beat.

Electret mics require a DC bias voltage as well as a pre-amp.

Alternative sources for mics and suitable power supply/pre-amp boxes include

The Sound Professionals http://www.soundprofessionals.com
These folks have some good informational pages that will help you understand
what you want and why

Microphone Madness http://www.microphonemadness.com
These folks have some interesting mics

My whole field kit weighs less than 2 lbs. including the Archos. The power
supply runs on a 9 v battery for up to 75 hours. I've got the whole thing
installed in a waterproof plastic case, with a small hole for the mic cable.
I made a mic holder out of PVC pipe and a rubber stopper.

> What are your best preferred recording settings that give best battery
> life:performance ratio for the following situations:
>
> *Lectures/conversations
> *Videos/movie
> *concerts
> *ambient/environment noise
> *any others you can think of!
>

I use Q=2 stereo, 44.1 for long spoken word recordings from FM radio. I
cannot detect any loss of quality.

For live music performances using batteries under 2 hours, you can go with
Q=5. Bump it up a notch if you can plug in the charger. I use a T shaped
stereo electret mic which gives some stereo separation. For "stealthy"
recording, you can clip two mono mics to a cap so the mics are as far apart
as your ears.

I've recorded ambient sounds at Q=3, but the major problem was that the mic
was omni-directional and the near field crickets overwhlemed all the sounds
in the distance. If you want to do much of this, look at a directional
mic.

I recorded a walking tour through city traffic at Q=3 stereo with a
hand-held wedge shaped electret mic. The voices of the tour guides were
clear, as long as I held the mic close enough. I picked up some interesting
artifacts of foot steps on loose sand over city pavement. If I did this
again, I would go to Q=4 or 5.
Received on 2003-11-07