Rockbox

  • Status Closed
  • Percent Complete
    100%
  • Task Type Bugs
  • Category Recording
  • Assigned To No-one
  • Operating System
  • Severity Low
  • Priority Very Low
  • Reported Version Daily build (which?)
  • Due in Version Undecided
  • Due Date Undecided
  • Votes
  • Private
Attached to Project: Rockbox
Opened by burgbach - 2003-04-01
Last edited by burgbach - 2004-11-15

FS#1156 - noise in record when reducing input gain

First, thanks for this marvelous piece of good features !!!

When recording, with a recording gain of 0 on the
jukebox, if I decrease the volume of the input signal
(I use an archos mic preamp, I decrease its volume), I
get an increasing noise. If I completely plug-out the
input cable, I get a very high noise (someting like a
half of the input peak meter).

I use an archos jukebox FM recorder, 1.30j firmware,
030325-0323 rockbox.

Closed by  christi-s
2006-03-19 14:50
Reason for closing:  Out of Date
Additional comments about closing:  

Please re-open if this is still a problem

Project Manager

…and I assume that this doesn’t happen when using the
Archos firmware?

you assumed correctly ;-)

Project Manager

I can’t repeat it on my FM Recorder. I don’t have the
external Archos mis. Can you repeat it with another analog
source?

First, I could not reproduce it, which was very frustrating for
me. Then, I turned off my jukebox, back on, and the noise
was back. Now, I can’t get it working without the noise
anymore. Attached is a test file, recorded with the mic. I’m
pretty sure it’s not the mic’s fault, because if I plug out the
analog source audio cable, you’ll ear the full noise (with HD
noises…).
The test file goes as follow : first, I say hello. The gain is max
(19.5 dB), there’s some noise, but that’s normal at this gain.
Then, I decrease the input volume on the mic preamp. You’ll
ear the noise increase. Then, back to full volume. Finally, I
plug out the analog source cable, and you’ll ear the full noise.
I’ll retry tonight with other sources.
Sadly, I can’t find the condition to switch from the “with-
noise” mode to the “without-noise” mode…

Project Manager

Did you ever come any closer to a solution to this?

no. Since this time, I did not used the “record” function
anymore. I switched back to a minidisc recorder because of
this noise.

Project Manager

I think I know the reason to this. I feel kind of silly not
to think about this earlier. The FM radio is connected to
the Line In as well, so it may very well be the radio that
is generating all this noise.

So is it possible to completely turn off the radio?

Project Manager

I’m afraid not. As a test, you could try to tune in to a
good station before recording, just to see if the noise
turns to music.

Strange, because this does not always happen… It seems
like if something is not always well initialized…

Project Manager

Maybe. Perhaps there is a difference if you have the
headphones connected or not (which is the FM antenna).

I was not aware that the headphones were the antenna… I’ll
try this.

I have some more information. I just tested it a little bit,
and now the situation is:
- if I go to the recording mode just after power on, I ear
the noise
- now, I go to the radio, and leave it
- back to the recording mode, no more noise.
So it seems that when I enter-leave the radio, it is well
turned off, but maybe it is not well initialized when
powering on the device.
I can reproduce this each time (tried 3 times).
I cannot find which version I use now, except that it’s the
flash version. The firmware screen is blank, and the version
screen says Ver. flashedition. I hope this is sufficient…

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