Thread: vinyl to flac?
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Old 2004-12-05, 04:51 PM
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Re: vinyl to flac?

Quote:
Originally Posted by moemusic
Over analyzing? Or just gun shy? When you make a noise profile all you are doing is taking a known noise sample and removing it. IF the noise exists it's removed. If it doesn't exist nothing is done.

When running a nosie filter in this manner you can watch the wav form change when the noise is filtered out. Run the noise filter again and no change. Try it
The noise sample is looped and mixed back in with the sourced audio with the filter and amplitude applied as specified in the settings. So if there is no noise matching the profile, the algorithm will add out-of-phase noise if there was none there. This is very much like the long-proven strategy used by 3-prong balanced cables. Since the noise is slightly variable and the sample is constant, the process is inaccurate and some degree of audible aritifacts can be introduced. Done properly, these artifacts become inaudible and insignificant. So this is why evaluation by a peer group is so necessary... many people (like my Uncle) would claim that mp3 artifacts at 160kb/s cbr are negligible but we're dealing with a much more discerning crowd here. From experience, I would highly recommend not running CEP/Auditon nr at 100%, but rather down closer to 60% to "cover your tracks", so to speak.

Quote:
Originally Posted by moemusic
In your example, it wouldn't matter if you ran all 3 profiles over each section. It's just more work. I've found that when i use a noise profile say from the silence at beginning of the track, not much is left for the noise profile at teh end of a track. But use the noise profile at teh beginning of the lp on the last track and then run the noise profile at teh end of the lp and you'll see more noise is filtered. That's from the physics of playing an lp. Too deep for me to understand fully but I don't need to lol..
Oh, I see. You're talking about making multiple passes, I understand now.

Quote:
Originally Posted by moemusic
Now I must emphize that when taking a silent sample for a noise profile it's very important that no music is present. I get to the end of a track, crank up the volume (my puter's hooked to stereo) and listen to find the place where's there's no music. Even a string slightly vibrating can affect teh music since it's part of the profile. If the beginning of the next track fades in then I write the time down for the end of a track and find where the sound is beginning. You only need a small sample. I try to get a 2-3 second sample. But sometimes yuo can't get that.

Another thing. Make sure any clicks/pops are removed in teh area you're taking your sample from.
Excellent points. Also make sure the beginning and end of the sample is cut on the zero crossings and that when the beginning is pasted to the end (no smoothing!) the waveform retains it's natural shape and no click/pop is introduced (zoom in and/or use spectral view together with your ears to double and triple-check this).

Also, I find it useful to turn off my computer system sounds when doing nr work... I've almost had my head ripped off a couple times when I had my volume turned up to 20 and windows goes "DUNT!!!".

Quote:
Originally Posted by moemusic
If useful, I can write a tutorial complete with screenshots. I don't have the web space for images tho.
Sounds great, I'd love to see it. Use http://www.imageshack.us/ to host your images, no membership is necessary and it's free.

Quote:
Originally Posted by moemusic
...I'd be glad to send someone a before and after sample and I'm sure you'll agree the noise reduction technique here is worthy of mastering vinyl boots. PM me if ya want a sample. I'll send something to one operson and they can be the ears of the group and/or pass it around.
I would absolutely love to hear your work some way or another. Preferably not out of print material since this is not allowed at TTD and I would want the samples available to everyone who's interested. This way, when they read your tutorial, they can hear samples of the results right away. I'll find someplace to host the samples for you.

Quote:
Originally Posted by moemusic
Oh about that forum. I believe many people are muscians and am not sure how they'd take to free distribution of boots so might want to conceal this.
Thanks, great tip.
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