Differences between version 28 and revision by previous author of SoundProcessingNotes.
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| Newer page: | version 28 | Last edited on Tuesday, February 17, 2004 5:57:32 am | by JeffWelty | Revert |
| Older page: | version 27 | Last edited on Saturday, February 7, 2004 12:38:57 am | by AristotlePagaltzis | Revert |
@@ -40,11 +40,15 @@
GWC works really well. I followed the suggested notes at the above URL, which I'll summarize here:
First of all, I amplified the track. GWC seems a bit buggy with this - it won't always amplify correctly. If the waveform doesn't increase in amplitude, it hasn't been amplified. I found if you wait till after processing to amplify, some noise still gets through.
+
+(Jeff Welty here - see my comments below about GWC amplify)
* Run the strong declick tool. The first time I ran this I got about 7000 clicks removed. The second time, about 400, and the third time, about 20. This was 'good' enough, so I moved onto the next step:
* Run the decrackle tool. This removed most of the remaining crackle on the recording.
+(Jeff Welty here -- it's worth a try at skipping this step to see if the denoise tool will clean out the remaining crackle. Avoid decrackling if possible because it attenuates the high frequencies)
+
* Run the denoise tool. Its suggested to use any lead-in you can, but I only lead-out noise available. It seemed to do just as well. I ran it first with the defaults, then used the suggested settings on the url above. It seemed about the same really, although with the speakers I have on this computer it is hard to tell.
At this point, the tracks were a LOT cleaner and sounded great.
@@ -74,8 +78,12 @@
!! Third Attempt
After a bit of thought, I realised one thing I might have been doing wrong. The GWC amplify tool didn't seem to work particularly well, and when it did work I think I was using it wrong. It puts up a prompt with 5 entry boxes - Left Channel Stard, End, Right Channel Start, End, and Feather Width (set to 2000, I left it). It stated the the maximum gain without clipping for this track was 25.something, which was a figure I'd seen elsewhere. So I set the 'End' values to 25. Which, in hindsight, probably meant an increasing amplification as the wave progressed, and which would have accounted for the increased noise further on in the CD and the poor noise correction performance - I doubt it can handle fixing an increasing noise source.
+
+(Jeff Welty here --
+Yes, the Left Channel Start value is the amplification to be applied to the start of the selected region in the left channel, and the Left Channel End value is the amplification to be applied to the end of the selected region in the left channel. This allows you to apply fade ins, or fade outs if you desire. The feather width is a little window that "feathers in" the amplification. If there was no feathering, then the amplification could introduce a click into the audio.
+End Jeff Welty's comment)
So this time, I used DartPro (couldn't be assed finding another tool to do this, in case it wasn't the problem after all) to increase the gain, and then ran my declick/decrackle/denoise routine over this file. The waveform looked a lot better, and it sounded fine.
I also discovered that GWC will mark track boundaries just as well as gramofile will, and will export a .toc file for me too. Better and better. I processed both sides, merged the two .toc files (the .toc format allows you to specify a filename and a start/end offset into the file, so you dont actually need to split the original file up :)
