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#1
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digital noise reduction question
Regarding digital NR (e.g., denoising plugins, CEDAR, NoNoise, etc) to reduce hiss -- curious to know what experienced recording engineers/sound gurus think -- is an audible increase in the S/N via digital NR *always* accompanied by some unwanted , degradative artifacting affecting the music? Or can digital NR ever be 'harmless' with respect to the music -- i.e., leaving the music sounding the same (or better), while appreciably reducing the hiss? FWIW it has been my experience (using Coole Edit/Audition) that some light passes of digital NR with Audition can leave the music subjectively intact while reducing hiss. But i haven't ever tested the difference rigorously. -- -S It's not my business to do intelligent work. -- D. Rumsfeld, testifying before the House Armed Services Committee |
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#2
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On Thu, 31 Mar 2005 22:50:05 -0500, Steven Sullivan wrote
(in article ): Regarding digital NR (e.g., denoising plugins, CEDAR, NoNoise, etc) to reduce hiss -- curious to know what experienced recording engineers/sound gurus think -- is an audible increase in the S/N via digital NR *always* accompanied by some unwanted , degradative artifacting affecting the music? Or can digital NR ever be 'harmless' with respect to the music -- i.e., leaving the music sounding the same (or better), while appreciably reducing the hiss? FWIW it has been my experience (using Coole Edit/Audition) that some light passes of digital NR with Audition can leave the music subjectively intact while reducing hiss. But i haven't ever tested the difference rigorously. Steve, That's your next challenge. Get back to us with the results.  Regards, Ty Ford -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric stuff are at www.tyford.com |
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#3
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Steven Sullivan wrote:
Regarding digital NR (e.g., denoising plugins, CEDAR, NoNoise, etc) to reduce hiss -- curious to know what experienced recording engineers/sound gurus think -- is an audible increase in the S/N via digital NR *always* accompanied by some unwanted , degradative artifacting affecting the music? Yes, but the artifacts might or might not be audible. The whole notion here is that you're making compromises and the compromises that you make need to be carefully thought out and checked on good monitors. Or can digital NR ever be 'harmless' with respect to the music -- i.e., leaving the music sounding the same (or better), while appreciably reducing the hiss? It will never sound the same, but it will sound close enough for the job. Things like click and pop removal are pretty innocuous. Broadband noise reduction is anything but innocuous and decrackling can also do some terrible damage if you aren't careful. FWIW it has been my experience (using Coole Edit/Audition) that some light passes of digital NR with Audition can leave the music subjectively intact while reducing hiss. But i haven't ever tested the difference rigorously. Yes, and you may find several light passes give you better noise floors and fewer artifacts than one heavy one, too. The key is to have good monitors so you can hear what is really going on and you can back off when things get out of hand. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#4
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#5
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"Scott Dorsey" wrote in message
... FWIW it has been my experience (using Coole Edit/Audition) that some light passes of digital NR with Audition can leave the music subjectively intact while reducing hiss. But i haven't ever tested the difference rigorously. Yes, and you may find several light passes give you better noise floors and fewer artifacts than one heavy one, too. The key is to have good monitors so you can hear what is really going on and you can back off when things get out of hand. In my experience, it's also heavily program-dependent. Some items let me do up to 4dB of noise reduction at a pass, others gag on 1dB, and I haven't noticed any pattern that would let me predict how a particular recording will react. Peace, Paul |
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#6
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I have had one experience of using CEDAR noise reduction, along with
appropriate mastering, on the track "Drowsy Maggie" by Irish flute player Matt Molloy. The "original" on his "Heathery Breeze" CD and the version on "Wooden Flute Obsession" volume 1 (http://www.worldtrad.org) with hiss minimized/removed. Everyone's been quite happy with the WFO version, and I'm personally quite pleased. Kevin Krell International Traditional Music Society, Inc. Steven Sullivan wrote: Regarding digital NR (e.g., denoising plugins, CEDAR, NoNoise, etc) to reduce hiss -- curious to know what experienced recording engineers/sound gurus think -- is an audible increase in the S/N via digital NR *always* accompanied by some unwanted , degradative artifacting affecting the music? Or can digital NR ever be 'harmless' with respect to the music -- i.e., leaving the music sounding the same (or better), while appreciably reducing the hiss? FWIW it has been my experience (using Coole Edit/Audition) that some light passes of digital NR with Audition can leave the music subjectively intact while reducing hiss. But i haven't ever tested the difference rigorously. |
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#7
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On Fri, 1 Apr 2005 03:50:05 +0000 (UTC), Steven Sullivan
wrote: Regarding digital NR (e.g., denoising plugins, CEDAR, NoNoise, etc) to reduce hiss -- curious to know what experienced recording engineers/sound gurus think -- is an audible increase in the S/N via digital NR *always* accompanied by some unwanted , degradative artifacting affecting the music? Or can digital NR ever be 'harmless' with respect to the music -- i.e., leaving the music sounding the same (or better), while appreciably reducing the hiss? FWIW it has been my experience (using Coole Edit/Audition) that some light passes of digital NR with Audition can leave the music subjectively intact while reducing hiss. But i haven't ever tested the difference rigorously. -- I think _every_ broadband noise reduction system exibits the comb filtering effect. The artifacts can be concealed by good equalization techniques but the sound does remain changed to a various extent; it depends on how aggresive is one going in removing the noise. Multiple pass / very light settings seem to have the least adverse effects. A good monitoring and judgement is a must. Tests by direct a/b comparison can reveal also slightest differences (often I do it in the morning with very "fresh" ears and the result is also quite often "Delete", grumbling "God Allmighty, was that really me the night before?). If you can't fight the noise, live with it. This is far better than wrecked recordings. No money given into any such tools warrants instant results. Edi Zubovic, Crikvenica, Croatia |
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#8
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Question: In doing multiple light passes, would you use the original
noiseprint every time? Or take a new noiseprint from the noise-reduced file? Peace, Paul |
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#9
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"Paul Stamler" wrote in message
... Question: In doing multiple light passes, would you use the original noiseprint every time? Or take a new noiseprint from the noise-reduced file? New noise print. |
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#10
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On Sat, 02 Apr 2005 17:35:21 GMT, "Paul Stamler"
wrote: Question: In doing multiple light passes, would you use the original noiseprint every time? Or take a new noiseprint from the noise-reduced file? Peace, Paul -- Yes, I'd use the new one. But there are other possibilities, especially at worn and noisy records, where the original noiseprint could be temporarily saved and it could be experimented with, esp. decreasing volume, inverting etc. There are many possibilities for experimenting. Then you'd replace the original noiseprint such altered one and try. The utmost aim is to have the original sound preserved -- altered or vanished quitetest parts, absence of recorded natural reverberation and alike could be a warning. As I noticed the most common mistake is made by trying to remove all the noise. But as the noise is very broadband, the damage is obvious. To me, it is better to make the noise unobtrusive enough so that it wouldn't distract a listener from hearing and make it so that it would the least mask the sound picture. As to impulse noise the risk is, if you remove "Ticks" merely by lowpass filtering, you in many cases would have a "Tock". And such filtering to less than 7 kHz alters the sound too much as it gets unduly loud and aggressive. Low-Q filters are better choice in such tasks. At many old recordings I have taped decades ago, I like the sound of LP filters of the old EMT 930 turntables, which had them built-in. It seems to me, that they can't be easily digitally reproduced but they were very smooth indeed. OK, impulse noises are easier to deal with, the big ones manually and there are also good automatic decracklers such Algorithmix/Waves ones, the Sonic Forge (now Sony) "Click and Crackle Removal" from their noise reduction package sold separately and some others. Careless usage of some declickers results in nasty increased and altered clicks and distorsion and with decracklers, the result can sound worn and dulled. Interesting, in Sound Forge 8 there is the "Express FX Audio Restoration" plugin, which sounds to me as if it is dealing with formants too; but I don't like results -- perhaps it's only me. Dealing with hiss is far more risky, though. To be honest, I avoid removing it by use of any noise reduction tools, but I have some other mehods to reduce it somewhat. However, so reduced noise means also a dulled result too so a good balance is important. Edi Zubovic, Crikvenica, Croatia |
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#11
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Scott Dorsey wrote:
Steven Sullivan wrote: Regarding digital NR (e.g., denoising plugins, CEDAR, NoNoise, etc) to reduce hiss -- curious to know what experienced recording engineers/sound gurus think -- is an audible increase in the S/N via digital NR *always* accompanied by some unwanted , degradative artifacting affecting the music? Yes, but the artifacts might or might not be audible. The whole notion here is that you're making compromises and the compromises that you make need to be carefully thought out and checked on good monitors. Or can digital NR ever be 'harmless' with respect to the music -- i.e., leaving the music sounding the same (or better), while appreciably reducing the hiss? It will never sound the same, but it will sound close enough for the job. Things like click and pop removal are pretty innocuous. Broadband noise reduction is anything but innocuous and decrackling can also do some terrible damage if you aren't careful. FWIW it has been my experience (using Coole Edit/Audition) that some light passes of digital NR with Audition can leave the music subjectively intact while reducing hiss. But i haven't ever tested the difference rigorously. Yes, and you may find several light passes give you better noise floors and fewer artifacts than one heavy one, too. The key is to have good monitors so you can hear what is really going on and you can back off when things get out of hand. I understand all that. But it's not quite what I'm asking. I'm asking what 'clsoe enough for the job' means. Think of my question this way: Suppose I believe that digital broadband NR *inevitably* degrades the music -- degrades the 'signal' as well as the noise. Even when applied by careful, experienced ears using great monitors. On that basis I advocate never using digital broadband NR. It's better to leave the hiss as is. Always. This isnt' my stance, btw. But it is pretty much the stance of many audiophile/'purist' types -- including some who are pros, like Steve Hoffman. Do other pros in their heart of hearts agree with that belief, even if they still use digital NR? Are they accepting a compromise? Or do they believe that you really *can* reduce hiss digitally without the music taking a hit? -- -S It's not my business to do intelligent work. -- D. Rumsfeld, testifying before the House Armed Services Committee |
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#12
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Steven Sullivan wrote:
I understand all that. But it's not quite what I'm asking. I'm asking what 'clsoe enough for the job' means. That depends on what the job is. If you're doing something for a quick broadcast job, close enough is a lot closer than it would be for a CD issue. My notion of 'close enough' is very different than what the NoNoise butchers at Madacy Records consider close enough. Think of my question this way: Suppose I believe that digital broadband NR *inevitably* degrades the music -- degrades the 'signal' as well as the noise. Even when applied by careful, experienced ears using great monitors. On that basis I advocate never using digital broadband NR. It's better to leave the hiss as is. Always. There are folks who feel this way, and that's fine. They can listen to the originals. For a lot of material, I completely agree with them. Other material may be in such bad condition that I disagree. This is like asking how much chocolate is enough for chocolate ice cream. It's a judgement call. And it's not the same for ice cream that goes in an ice cream cake and ice cream that is eaten alone, too. This isnt' my stance, btw. But it is pretty much the stance of many audiophile/'purist' types -- including some who are pros, like Steve Hoffman. Do other pros in their heart of hearts agree with that belief, even if they still use digital NR? Are they accepting a compromise? Or do they believe that you really *can* reduce hiss digitally without the music taking a hit? Everything you do, everywhere, everytime, is accepting a compromise. That is part of the job. The difference between good and bad engineering is knowing how to make the right compromises for the situation. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#13
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#14
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On Apr 4, 2005, Steven Sullivan commented:
Think of my question this way: Suppose I believe that digital broadband NR *inevitably* degrades the music -- degrades the 'signal' as well as the noise. Even when applied by careful, experienced ears using great monitors. On that basis I advocate never using digital broadband NR. It's better to leave the hiss as is. Always. --------------------------------snip---------------------------------- I learned a long time ago that "never" and "always" are two words you have to use very, very carefully -- especially with engineering and artistic decisions. What Scott says elsewhere is true: noise-reduction is like any tool. You can use it well, or you can use it badly, like EQ or compression or anything else. The great thing about all these tools is that they have knobs, and you don't have to run them up to "11" all the time. Sometimes a little bit works best; sometimes switching them in at some point, and bypassing them elsewhere is best. I find there's rarely a "one size fits all" adjustment for an entire song, especially with NR. But to say there's never a time when noise-reduction can work well is not true. I think the real key, though, is just getting good source tapes. Obviously, a 2nd-generation tape, played back clean, is going to sound better than a 5th-generation tape that's been noise-reduced to death. I think a lot of times, when you hear a muddy, heavily-gated song on a CD, the reason why that happened is because the label wasn't willing to take more time to search for a better source tape. Great source tapes rarely need any NR or drastic EQ, and on that, I'll generally agree. (But note that I don't use the words "never" or "always.") --MFW |
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#15
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Marc Wielage wrote:
I think the real key, though, is just getting good source tapes. Obviously, a 2nd-generation tape, played back clean, is going to sound better than a 5th-generation tape that's been noise-reduced to death. I think a lot of times, when you hear a muddy, heavily-gated song on a CD, the reason why that happened is because the label wasn't willing to take more time to search for a better source tape. Great source tapes rarely need any NR or drastic EQ, and on that, I'll generally agree. (But note that I don't use the words "never" or "always.") Noise reduction can reduce noise. But it can't do _anything_ about distortion. I often have people sending me 78 rpm acetates that were transcribed (using 1930s technology) from a 16" 33 rpm transcription disc. Comparing the dub with the original, it's amazing how much generation loss there was back then. And often you can hear that the original is mistracking on playback, but there is nothing you can do about it. Another personal gripe is getting tapes that were dubs made with incorrect azimuth settings. A clean transcription from the earliest possible generation goes a long way toward getting good sound. NR is just a nice addition now and then. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#16
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On Apr 6, 2005, Scott Dorsey commented:
Another personal gripe is getting tapes that were dubs made with incorrect azimuth settings. A clean transcription from the earliest possible generation goes a long way toward getting good sound. NR is just a nice addition now and then. --------------------------------snip---------------------------------- Yeah, amen to that. As an illustration: about ten years ago, I was working on a project for 20th Century-Fox, doing a digital restoration on the 1954 Richard Burton film PRINCE OF PLAYERS. They sent over a stereo track made in the 1970s, and it really sounded horrible. After trying to use it for a day or two, I called the studio and asked, "hey, is this all you have? Because it really sounds terrible." Basically, I think they had done the transfer and not checked the azimuth correctly, and the tape sounded muddy and dull. Fox checked their vault and told me the only other thing they had in stereo was the original 4-track 1954 mag master! I gulped and had them send over that. I had to clean the mag heads every five minutes or show because the mag was disintegrating slightly, but it sounded about 500% better than the 1970s transfer. In fact, for several weeks afterwards, I used this track as a demo (on digital tape) to show people just how could a 40 year-old recording could sound. Quite an illuminating experience. --MFW |
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#17
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"Marc Wielage" wrote ...
Fox checked their vault and told me the only other thing they had in stereo was the original 4-track 1954 mag master! I particularly liked the use of the phrase "only other"! :-) |
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#18
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On Sun, 17 Apr 2005 21:04:18 GMT, Marc Wielage
wrote: On Apr 6, 2005, Scott Dorsey commented: Another personal gripe is getting tapes that were dubs made with incorrect azimuth settings. A clean transcription from the earliest possible generation goes a long way toward getting good sound. NR is just a nice addition now and then. --------------------------------snip---------------------------------- -----------8---------------------too------------------------------------- Fox checked their vault and told me the only other thing they had in stereo was the original 4-track 1954 mag master! I gulped and had them send over that. I had to clean the mag heads every five minutes or show because the mag was disintegrating slightly, but it sounded about 500% better than the 1970s transfer. In fact, for several weeks afterwards, I used this track as a demo (on digital tape) to show people just how could a 40 year-old recording could sound. Quite an illuminating experience. --MFW See? --You've got a bingo. Unfortunately, getting a decent (ie. early generation) dub, not to speak about a master, isn't easy. Often, one has to pull something out of nothing because "nothing" is all that's available. I had to better out a gramophone record, mono, from that times, where the cutting tape deck has been obviously misaligned and cut that way -- a bad work. I did what I could but the sound is f-l-o-a-t-i-n-g. I think that somewhere a original tape _might_ exist (sometimes they don't any more), but then, the masters are of course treated as an asset. Edi Zubovic, crikvenica, Croatia |
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