cleaning vinyl audio?
Reply #50 – 2009-03-01 18:53:00
Hi Paul, nice to meet you too. I see you're located in "London-ish". So am I (Watford, actually). So if you feel the urge to meet up sometime it could probably be arranged. I once met Derek Higgins (author of Wave Corrector) and we had a good old chin-wag. Yes, I'd like that. I'm in Slough, no distance at all. PM me through HA if you like and we can exchange email addresses.I agree about the need to zoom in [in spectral view] to see the clicks. It's the same with Wave Repair. My personal view is that spectral view is useful when you're doing a manual repair by listening. When you hear a click, zoom in around the general area, switch to spectral view, and the click stands out quite clearly. Yes, I'd agree with that, based on what I saw in CE. It's certainly a tool that has its uses.Other glitches that lack high frequencies (plops and thuds) are much harder to spot. Sometimes you'll see an isolated "splodge" in the spectrogram. Quite often it's easier to spot plops and thuds in waveform view: there can sometimes be an obvious DC-like shift in the general waveform. But even once you've found such a glitch, fixing it can be maddenly difficult. I admit to sometimes giving up and leaving the original thud present, because all attempted repairs make things no better or worse. Have a little play with VinylStudio. It's good at fixing things like that, once you have located them. Not always so good at finding them though, although, as you say, they often stand out in the waveform display/Regarding clicks introduced by the hiss filter. This of course is pure speculation on my part, but assuming VinylStudio uses FFTs to implement its hiss filter, my experience has been that unless you apply some sort of windowing so that the overlapped FFTs are "faded in" to each other, discontinuities at the boundaries occur, leading to "ticking". A filter might remove those discontinuites. But if this is what's happening in VinylStudio, then the rumble filter is simply masking something that probably ought to be dealt with by windowing the overlapped FFTs. But I reiterate that I have no idea how VinylStudio's code actually works, so if you already window your FFTs, please don't take offense! No, that's fine. We do overlap our FFT's (of course!) and the clicks introduced in this way are very faint, but they are there. I have some recordings with very high amplitude rumble on the leadin (I think it might be an MP3 artefact, actually) which is probably why I picked this problem up. The rumble filter is applied *before* the hiss filter, and my private theory is that the large low-frequency component increases the discontinuities at the edges of the FFT windows to the extent that the overlap cannot mask them. With the rumble 'pre-filter' turned on, this low frequency component is removed before the hiss filter processes the audio, so the problem goes away.Seems like we're aiming at different user types. Wave Repair is primarily aimed at manual repair - fiddling with the waveform at ultra-fine levels of detail. My view is that automatic declickers sometimes do a good job on "medium level" clicks, but I've yet to find one that deals with big pops and splats, and most of them miss the tiny ticks. I'm kind of obsessive about my restorations, so I have to get in there and fix up things that auto declickers get wrong. I've never seen VinylStudio, but from what I've read here it sounds as if it's targeted at a more automated restoration process. So the two tools could be complementary. (Seems I should download an evaluation copy and try it out). On the other hand, people who are only interested in automatic cleanup can just ignore Wave Repair - it's definitely a tool for "geeks". Yes, I think we are, and yes, VinylStudio aims to automate as much of the process as possible. It has decent manual repair facilities though, give it a go if you like. Let me know your email address and I'll generate a license key for you. We've (ok, ok, it's just me ) also worked hard on the 'tiny ticks' problem, but there are always a few that sneak through. My own view on automatic click scanning is: it can save a ton of time but are you prepared to live with the damage it can do to your percussion? It can also occasionally distort or soften 'rasping' sounds, but that is rare in VS thanks to a super-duper proprietary algorithm of which I am unjustly proud. The important thing, really, is to be aware that these problems exist and also to be aware that the default settings might not be the best for any particular piece (or section) of music. We try to explain all this in the help file, but you now what people are like...CE2000 is indeed a wonderful program - IMHO the finest affordable general purpose audio editor there ever was. What a shame that when Adobe bought out Syntrillium, they chose to dump CE2000. You & I aren't trying to replace it, but somebody needs to. For sure, the install files are readily available (from my own website, for example), but activation keys are not. New users are either forced to use illegal keys or miss out on a wonderful program. Couldn't agree more. Adobe wrecked it. I am lucky to have a copy. Cheers and do PM me - Paul.