This was originally posted to the rec.music.bluenote newsgroup in September 2000. I keep getting comments on it, so I thought I would post in on the site for easier access. The newsgroup discusses jazz recordings, hence most of the examples come from a jazz background. I have expanded it in response to questions I’ve received since the original posting. Since this post, Adobe bought Syntrillium and renamed Cool Edit Pro to be Adobe Audition. The original suggestions for Cool Edit Pro still largely work for Adobe Audition as of Audition 3.
I was interested to see the comments on using Cool Edit to convert LPs into CDs. As the Cool Edit documentation mentions, you really need to do some trial and error to find what works best for you in terms of noise reduction vs. music reduction. Lots of what I read in the posts sound like people are turning the noise reduction and click/pop functions up all the way. This is what you could call a mid-80’s Columbia setting: it may get rid of all the noise, but in most cases it takes a good chunk of music with it. Some people may like this, but many will want to use less aggressive noise reduction settings.
So I thought I’d share what works for me in hopes that it helps as a starting point for other folks. Years ago I saw similar posts that got me started this way.
Note that this is using Cool Edit Pro (not 2000) or Adobe Audition with a good-quality 20- or 24-bit soundcard (not the sound card that comes with most PCs). The extra bits really do matter in doing the processing to get rids of clicks and stuff without getting rid of music. I have used a Lynx One, a Gadget Labs Wave/424, and a 20-bit Echo Darla card, all of which sound great.
Anyway, here’s my approach:
Record into Cool Edit using 32-bit resolution.
Get rid of the really big pops manually. Zoom in on the big pop, so you can select just the pop, not the surrounding music. Use the same numbers in the click/pop eliminator as listed below, and use the “Fill Single Click Now” button. (If you have too much music selected, Cool Edit won’t let you use “Fill Single Click Now.”)
Amplify up to 100%. That is, use Transform->Amplitude->Amplify. Set the “Peak Level” in “Calculate Normalization Values” to 100%, then hit “Calculate Now”. This is more important for 32-bit resolution than 16-bit. Make sure you do this before dividing the album into separate tracks. Check both sides of the album first, and use whichever amplification value is lower for both sides of the album. You want the same amplification value for both sides, so that’s why I use Amplify rather than Normalize.The main exception is if the LP master made the last track on each album side softer in order to avoid distortion. In that case, you may want to amplify those last tracks more than the others. Bob Seger’s Noah is one LP where I had to do this.
Divide into separate tracks if appropriate. The shorter files are easier to work with.
- Run the click-pop eliminator. I’ve stored my favorite values in a preset:
Level Detect Reject Max 50 55 Avg 40 48 Min 12 18 Second-level verification on Multiple passes off Pop Oversamples: 12 Run Size: 25
Usually, I leave “detect big pops” off and get them later to avoid losing drum sounds. If crackle is everywhere on the LP, I turn “smooth light crackle” on, otherwise I leave it off.
I do not use the “Auto Find All Levels” button. Rather, I bring in the preset, then use the “Find Threshold Levels Only” button.
This will not get rid of all the clicks and pops but is as far as I feel comfortable going with an automated process. Sometimes I will use more aggressive settings (like turning multiple passes on) for small problem spots in the LP, especially fades. At other times there’s nothing to do but go in and remove some of the clicks manually. How much you do depends on how much of a control freak you are. I’m an engineer so I tend to be pretty nit-picky about it.
- Now run noise reduction for the non-click noise. I use the following settings:
70% noise reduction level (not 100%!)
FFT Size 8192
Precision Factor 7
Smoothing Amount 2
Transition Width 2
Newer versions have added “Reduce by x dB” and “Spectral Decay Rate” options. I have left them at the defaults of 40 dB and 65% and it has worked fine.
I try to get a 2-second piece of silence from the beginning of the side and the end of the side for the noise profiles, using the one that best matches the noise before the track. The “silence” is actually the LP surface noise and rumble that you want to eliminate. The beginning of the LP side is usually the easiest place for this, but the surface noise changes from the start to the end of the LP side, so multiple samples between songs are even better. Make sure that you don’t get any pre-echo or other music into this sample! You can go down to half a second or so if necessary.
- Convert the 32-bit file to 16-bit for CD recording, using Edit->Convert Sample Type. Turn dithering on, and select “Noise Shaping (44.1 kHz).”
When I follow these steps, I find the CDs don’t lose ambiance compared to the LP, but they do gain clarity from having more signal and less noise. It’s pretty much cookbook except for getting rid of the last few clicks and pops. The same steps work well for my jazz, rock, and classical LPs. My jazz pride and joy so far is the CD version of Herb Pomeroy’s Pramlatta’s Hips LP from 1980 (I’m not holding my breath for that one to be reissued commercially on CD).
I don’t work for Adobe, I’m just a satisfied customer. I hope this helps some folks have better experiences than they’ve had to date!