Subject:pops in audio

Posted by: joejon

Date:4/14/2004 9:10:02 AM

I have one band music file that has pops/clicks that are helped some by using the Noise Reduction Click and Crackle plug-in, but they don't completely go away. I read a post on a similar subject, but my pops are always in the same location. I defragmented, that didn't help. They sound like when you touch something and there is static electricity and you hear a snap/pop. I don't know if it's a certain instrument or what. It is really difficult to single it out and what is causing it. This is the only file that does this and I have three other songs that were recorded at the same location and time which don't have any of this strange popping. Any suggestions?
Thanks

Subject:RE: pops in audio

Reply by: Sonic

Date:4/14/2004 10:03:07 AM

Pencil them out?

J.

Subject:RE: pops in audio

Reply by: TheHappyFriar

Date:4/14/2004 10:03:28 AM

if the pops are short (couple samples) you could just delete the samples and see how it sounds. that might work.

Subject:RE: pops in audio

Reply by: joejon

Date:4/14/2004 1:03:34 PM

I usually can find the clicks and fix them, but for some reason this file is different. I zoomed in to try and find the individual pops, but I don't see anything unusual in the waveform. I tried to pencil what I thought might be some of the pops, but that didn't help. There are so many of them anyway (at least 60 or so), it would take forever to find them and pencil them out. I ran a click and crackle plug-in at click shape of 8, sensitivity 20 and then again at click shape 6, sensitivity 20. This helped a little, but I still can hear them. It's sounds like a tape in a deck that needs to be demagnetized.

Subject:RE: pops in audio

Reply by: joejon

Date:4/17/2004 1:05:07 PM

I was experimenting with a lot of different things, including processing in various orders. I normalized 1st, before using noise reduction. I didn't use the restore clipped peak option as I did before. For some wierd reason, I only had about 4 pops in my audio, where before I was at least 60. It seemed to make a difference, but I don't understand why. If anyone has an explanation to this, I would like to understand why it worked. I always thought noise reduction should be the 1st step and I've never had any problems before using it 1st.
Thanks

Subject:RE: pops in audio

Reply by: SonyTSW

Date:4/18/2004 7:59:15 PM

You didn't mention exactly what format this audio file is, but if it is an ADPCM format then an audio proxy file needs to be created if you load it into Sound Forge 7. This is the nature of the ADPCM algorithm, each sample is dependent on the sample that precedes it and randomly accessing the file can be problematic. Unfortunately Sound Forge 7 does not automatically create a proxy file for these specific formats (this will be fixed in a future update).

The workaround is to enable the Sound Forge 7 preference to always create an audio proxy file when reading compressed formats. Reload your file after you have set this pref and see if the pops are still a problem.

Sound Forge versions prior to version 7 will always read compressed formats using a proxy file so this is not an issue.

Subject:RE: pops in audio

Reply by: joejon

Date:4/19/2004 7:25:21 AM

The file was originally from my video camera, so it was an .avi file, which I then saved as a .wav file (Microsoft). But as I said, when I normalized before doing the noise reduction, I got very few of these static-type pops. When I did the noise reduction 1st and then the normalization and clipped peak restoration, then I got a ton of these pops/snaps. I don't know if this way of doing things would work everytime or not (normalizing 1st). That's why I would like to understand why a file of the same format, when I do the processing in a different order, why it would produce these static-type pops. I've never had this happen on any other file in which I do the noise reduction 1st, only on the one file. Is it best to always normalize 1st, before noise reduction or anything else and why (if so)?

Subject:RE: pops in audio

Reply by: rraud

Date:4/19/2004 11:52:19 AM

It is not nessesary to normalize before the NR process, It just helps a little by optimimizing the program AND noise levels. Make sure you get an accurate noise print too.
I assume your importing the AVI file so it stays in the digital domain? Does it sound okay on playback though the camera or deck?
Is the waveform clipped? If not, why do you need Clipped Peak Restore
Are you normalizing to Peak or RMS? RMS normalizing can cause clipping if the adjustment parameters are not correct.

If all else fails, do an analog transfer.

Subject:RE: pops in audio

Reply by: joejon

Date:4/19/2004 3:49:54 PM

Yes, my file is digital. Yes, it sounds okay before I do any processing (as far as not having the pops). There were a couple areas that were clipped, hence doing the clipped peak restore. I normalize using Peak.

Subject:RE: pops in audio

Reply by: Geoff_Wood

Date:4/19/2004 5:28:59 PM

Do you have anything in the effect chain ? A frequency boost could be causing clipping, which won't show in the displayed waveform (unless rendered).

Maybe try dropping the level a couple of dB .

geoff

Subject:RE: pops in audio

Reply by: UNKLETRAVELLER

Date:4/19/2004 6:21:08 PM

if it not a huge pop a bit of conpression does wounders.