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Crackling sound - buffer full ?
Posted: Fri Apr 02, 2010 8:13 am
by Pobinr
I sometimes get crackling that recorded as if momentarily the record function fails during recording. It only happens when I've used audacity a lot since the PC was booted up. Or when I have too many applications running. Even when I close all other apps it sometimes still occurs. Incidently my PC has 1.5GB ram. I'm running Audacity version 1.2.6 on XP. Is there a buffer I need to clear out ?
Thanks in anticipation
Re: Crackling sound - buffer full ?
Posted: Fri Apr 02, 2010 11:31 am
by Irish
Audacity needs instant, fast disk access when it is recording.
If the disk is fragmented, and the computer has to look for places to put the data, or if it has to go off and do a complicated spreadsheet calculation in the middle of writing to disk, then the next chunk of audio has come and gone before the computer can get to it.
Some general rules:
1. Audacity needs lots of free, un-fragmented disk space to store audio. (average 10MB per minute for 44100Hz 16-bit stereo. Twice that for Audacity's default setting of 44100Hz 32-bit. Double that again for storing the "Undo" data). De-fragment your hard disk regularly.
2. On top of that, Windows needs at least 10% free space on the disk, in order to run properly.
3. Don't try to record to an external disk drive or USB flash drive; they are generally not fast enough.
4. Don't run other applications when you are recording.
PO'L
Re: Crackling sound - buffer full ?
Posted: Fri Apr 02, 2010 4:16 pm
by Pobinr
Thanks Irish. I was aware of all that.
As I say, is there a RAM buffer I need to clear out, or set to larger size ?
Re: Crackling sound - buffer full ?
Posted: Fri Apr 02, 2010 9:02 pm
by steve
Pobinr wrote:is there a RAM buffer I need to clear out, or set to larger size ?
No, nothing like that. Though using a lot of effects can use up RAM. To clear all RAM that is used by Audacity, close and restart Audacity - that will release everything that Audacity is using.
If restarting Audacity makes no difference, then it's likely that something else is hogging resources. You can either go through and see what other processes are running, how much RAM and CPU they are using, or simply reboot.
USB interfaces are particularly susceptible to crackling or loosing connection if CPU activity goes too high (though other types of sound card can also be affected).
Re: Crackling sound - buffer full ?
Posted: Fri Apr 02, 2010 9:04 pm
by kozikowski
<<<is there a RAM buffer I need to clear out, or set to larger size ?>>>
I don't know, but this is a volunteer organization -- both the program and the help service -- so if you find out, do post back.
Koz
Re: Crackling sound - buffer full ?
Posted: Sat Apr 03, 2010 11:10 am
by Pobinr
I've been using a usb hardrive to record onto. So now will use C: drive instead & hope solves problem. Thanks for your replies.
Re: Crackling sound - buffer full ?
Posted: Sun Apr 04, 2010 1:37 pm
by waxcylinder
Use your onboard hard drive to record on to and edit on with Audacity - but when you export the finished audio files WAV and/or MP3 or whatever then you can export these to the external hard drive - and then delete the Audacity project to free up space on your hard-drive.
Though note carefully that ideally you should retain at least 2 copies of the audio files - on different discs. One copy of a data set is not enough - if and when you hard drive fails (one of mine did last year!).
WC