Rockbox mail archive
Subject: Re: Very low record levels using external mic
From: Christi Alice Scarborough (christi_at_chiark.greenend.org.uk)
Erik Owens wrote:
> This should be an easy question for experts to answer. I'm running
> Rockbox 2.2 (Flash) in my FM Recorder 20, and I have a Sony ECM-719
> electret condenser stereo mic (a photo is here:
> http://www.ofamily.net/ecm719.jpg and attached). The mic has a battery
> and on/off switch, which I guess means it has a pre-amp;
That's probably for phantom power rather than a pre-amp. Phantom power
is used to drive the microphone's recording apparatus, ie the mic is
active rather than passive and requires some power to operate.
> I have it
> plugged into the Line In jack, and I have Archos set to use "line in"
> as the recording source.
> Here's my problem: I cannot get a high enough recording level without
> tons of white noise (I mean "hissing") in the background. I've tested
> the mic on a different device and the volume levels are fine. On the
> Archos, however, even turning the gain up to 18 doesn't help much. (My
> voice recording is still faint, but the hissing noice is much
> lounder.) Do you have any suggestions?
Symptoms are definitely consistent with a lack of a pre-amp. If you
have a stereo with mic and phones sockets, you can improvise a pre-amp
out of that. That would at least provide confirmation as to whether
it's the lack of a pre-amp that's the problem.
Page was last modified "Jan 10 2012" The Rockbox Crew