FS#12663 - Periodically background hissing noise in a record

Attached to Project: Rockbox
Opened by Dominik Rutschmann (Dominik Rutschmann) - Monday, 07 May 2012, 22:13 GMT
Last edited by MichaelGiacomelli (saratoga) - Sunday, 13 May 2012, 22:28 GMT
Task Type Bugs
Category Recording
Status Closed
Assigned To No-one
Operating System Another
Severity Low
Priority Normal
Reported Version Daily build (which?)
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No


Clip+ RockBox Version: 88aeef9-120505

I made a recording and now there is a soft and not very loud hiss sound in the recording. But the hissing isn't constant. It occurs periodically and lasts for approximately one second.

I think that it may be caused by a to heavy CPU load while copying from the Ram to the internal memory, but thats just a wild guess.

It would be nice if this problem could be somehow fixed, because a clean recording is something nice to have. :)
This task depends upon

Closed by  MichaelGiacomelli (saratoga)
Sunday, 13 May 2012, 22:28 GMT
Reason for closing:  Duplicate
Additional comments about closing:  Seems like this is covered by FS#12291.
Comment by MichaelGiacomelli (saratoga) - Tuesday, 08 May 2012, 00:19 GMT
Perhaps the microphone picks up noise from the SD writes? Can you check if the hiss corresponds the frequency of disk writes (themes often have an icon that flashes during flash writes)?
Comment by Dominik Rutschmann (Dominik Rutschmann) - Thursday, 10 May 2012, 18:07 GMT
I now stumpled accidentally over an older report, where a person reports a similar or even the same problem:

He also comes to the same conclusion as I. The problem seems to be the CPU or memory writes - as you mentioned before. I also think that this problem may be eased by wiriting more frequent/constant but with less intensity (CPU usage). I expect that this work-around drains the accu faster but this compromis should be worth a clean recording. Maybe you could set this as a additional option in the recording menue, like: "Noisefree recording".
Comment by MichaelGiacomelli (saratoga) - Sunday, 13 May 2012, 22:27 GMT
That does sound like the same problem. I'll just close this task, and you can watch the original one.