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lossless normalization
macchipazzi
post Nov 14 2006, 20:05
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ppp

This post has been edited by macchipazzi: Apr 1 2008, 19:25
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Garf
post Nov 14 2006, 20:45
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QUOTE (macchipazzi @ Nov 14 2006, 20:05) *
if so, then is wav normalization only lossy in the fact that it's irreversible, or does sound quality actually get deteriorated?


Wait, wait, that's the same thing.

If we're saying that normalization of lossless data is lossy, then we don't mean that the sound quality will audibly detoriate. We're saying that this transformation can't be undone, because some information is lost. This loss can be considered detoriating the sound quality.

Because the idea of lossless is, well, not to lose anything, normalizing it is considered a bad idea.
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saratoga
post Nov 14 2006, 21:10
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If you just want to have files played at equal loudness without changing them, use replaygain. Its tag based so the actual audio data isn't changed, the tags.

Edit: Well it can be tag based. You can also make it change the files themselves.

This post has been edited by Mike Giacomelli: Nov 14 2006, 21:11
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Dynamic
post Nov 14 2006, 21:30
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QUOTE (macchipazzi @ Nov 14 2006, 19:05) *
hi, i know that wav normalization isn't lossless, but is there normalization for other lossless formats (ape/flac/wv/wm/whatever) that is lossless? or is the only lossless normalization for lossy compression?


No, it's not lossless if you apply the change to the audio in the file.

The best approach is to use a ReplayGain compatible player to standardise (normalise) the perceived volume on playback - it then simply multiplies the sample values by a pre-determined factor, which usually make the songs quieter. Foobar2000 can do the scanning to determine the scale factor, apply the tags and play back the audio with your choice of making tracks the same loudness, albums the same loudness or making no change to the original CD. If your soundcard supports 24-bit output, the multiplication (done in 32-bit floating point then downconverted to 24-bit) is essentially lossless, because the noise floor of your 24-bit output is below that of your 16-bit CD source (if it is a 16-bit source).

QUOTE (macchipazzi @ Nov 14 2006, 19:05) *
if so, then is wav normalization only lossy in the fact that it's irreversible, or does sound quality actually get deteriorated?

It introduces a certain amount of extra noise including dither, but at a level that's almost certainly inaudible. It does mean that you probably can't recover the bit-exact data you originally had.

QUOTE (macchipazzi @ Nov 14 2006, 19:05) *
i would love to be able to normalize lossless formats losslessly, so i don't have to convert all my lossless ripped vinyls to mp3 just so i can gain them and listen to them on my computer. i'd like to actually be able to listen to the lossless versions without having to crank my speakers to the max.

alternatively, does anyone know any way to rip vinyls at a higher volume in the first place? (and i know how to up the line-in recording volume level, but even when this is maxed my records still come out unlistenably low.)


First: Your vinyl rips will almost certainly have a noise floor above the noise floor inherent in 16-bit audio formats, so being precisely lossless shouldn't be an audible problem.

Second: I notice you're hoping to increase the volume of your Vinyl rips using only normalization. One of the wonderful things about good quality recordings, particularly those on vinyl is that they have a wide range of musical dynamics and sharp transients. It's sharp transients like percussion hits or orchestral sforzando climaxes that tend to be where the voltage (or sample value on your rip) reaches the extremes (most positive or most negative values). Standard peak-value normalization will only take the most extreme of these values to the absolute extreme sample value available and it won't actually make the loudness the same.

To get higher volume from the vinyl rip in the first place, you have to degrade the peaks using some form of limiting or dynamics compression either before sampling or using digital processing after sampling. This inevitably alters the sound to some degree and is certainly not lossless, but it's what is done in modern CD mastering, radio broadcasting and TV broadcasting.

The better approach for preserving audio quality (and that which is recognised by ReplayGain) is to turn up the loudspeakers, leave nicely dynamic material nearly unchanged (like your vinyl rips) and make the heavily limited and dynamically compressed material quieter so that they end up at around the same loudness.

You can even go so far as to take all you operating system sounds and (after backing them up!) replacing them with ReplayGained versions that are quieter so that your whole system sounds fine at the higher loudspeaker volume level.

Search for ReplayGain in the knowledgebase for more info.


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[JAZ]
post Nov 14 2006, 21:56
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Have you connected the output of the phono directly to your soundcard in?

If you've done so, then, there might be the problem. you should get a phono preamp, or use a mixer table with phono input in order to get a standard line out signal.

If you knew about this already, then, it might simply be the records, and you really need a signal preamp before your soundcard in. (you should be able to amplify it with the previously mentioned hardware)



[edit: phone -> phono]

This post has been edited by [JAZ]: Nov 14 2006, 21:57
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Tung
post Nov 14 2006, 22:41
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QUOTE
' date='Nov 14 2006, 14:56' post='449511']
Have you connected the output of the phono directly to your soundcard in?

If you've done so, then, there might be the problem. you should get a phono preamp, or use a mixer table with phono input in order to get a standard line out signal.

If you knew about this already, then, it might simply be the records, and you really need a signal preamp before your soundcard in. (you should be able to amplify it with the previously mentioned hardware)



[edit: phone -> phono]


JAZ is right. You absolutely need to get a better level out of your turntable. I've got a 2-channel amp (my old stereo amp) that has photo inputs for the 2 types of cartridges. Once I've got that hooked up to the turntable, then I just use the line out from the amp to go into the soundcard.

Ideally, you'd want to boost the gain high enough that it won't clip the soundcard input, but when I use line out I have no control over the level - however, my soundcard has record level settings, so that helps.


I should add that I backup the files created after ripping the vinyl, then I tweak copies of the files to remove pops/clicks and such. These files I normalize, and add to my listening library.

But you ought to keep the original ripped files somewhere.


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AndyH-ha
post Nov 15 2006, 00:38
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A while back I responded to a "lossy normalization" thread saying it is rather silly to call normalization lossy, and furthermore, most of the professional audio world does not. While there is a permanent change, it does not result in any artifacts or other loss of quality such as can be the result of lossy compression. This generated a great deal of shouting and hand waving. I don't want to start that again. I.AM.NOT.SAYING.THERE.IS.NO.COMPLETELY.UNREVERSIBLE.MODIFICATION.IN.THE.DATA.

I never implied that normalization does not change the file permanently, only that the change is in no way an audio quality issue. The audio becomes louder or softer, nothing more. There is no deterioration. Worrying about it on something recorded from a phonograph record is doubly silly.

If you record the same LP two times, you get two different results. If you do it ten times, you get ten different results. It is not possible to get the same thing twice. This is easy enough to measure but, unless your equipment is pretty poor, it is not possible to hear the differences -- except maybe by paying attention to the variations in some clicks and pops rather than by listening to the music. Do you worry that a subsequent playing of an LP is less quality than a former one, or that you have to play it many times until you just happen to experience the best playback your equipment can manage?

Furthermore, the music from vinyl is setting on top of a great deal of noise. This noise is much greater than the difference you will get by normalizing, then returning the file to the original level. This unavoidable disk noise completely and totally swamps the difference due to amplifying, de-amplifying. Furthermore, if you do any kind of clean-up to the recording, such as declicking and noise reduction, the changes to audio quality will be exceedingly enormous compared to that from normalizing.

Just as an experiment, I ran a track through the process. I normalized, then de-amplified back to the original level, then compared that result to the original. Working in my normal 32 bit format, the average difference level across the track was -101dB. The background noise for that track measured -54dB. You think will be able to detect that -101dB difference as some kind of "quality" deterioration?

By the time I'm through with that album, the (normalized) background noise will probably be around -65dB, maybe lower. This alone is a much larger change to its listening quality than that due to the normalization. The noise level will still be huge compared to the amplify, de-amplify difference however.

For comparison, I extracted a CD track from a Stereophile demonstration disk. Its peak level is -7.16dB and its average level is -28dB. It has a wide dynamic range. I left it in 16 bit format for this test. The average difference from the procedure described above was -92.5dB. This difference by itself is not below hearing level, but I wager it represents a difference that you will never ABX.

One cautionary consideration. Do not normalize to 0dB, use something a bit less such as 98%. This is always good advice because some DACs don't handle 0dB as well as they should, and 0dB represents a uncertainty of sorts to software math, at least in the program I use. Doing the same test tracks normalized to 100% rather than my usual 97% produced much larger differences (-93dB for 32 bit and -85dB for 16 bit). I don't know why this is so, it is just an empirical observation. Those still do not represent any deterioration of quality in what you will hear, however.

It is most common to put a mixer in between the phono preamp and the soundcard to adjust the input level to a better level. Only the line level preamp aspect of the mixer is need for this. A line level HiFi preamp will do as well but these tend to be more expensive.

Unless something is unusual in your equipment, as in tending towards the poor quality end of the scale, your end product will probably be just as good by recording, then normalizing. There is some small chance this is not so if you are using a 16 bit soundcard. Then possibly you will improve the quality by inserting a preamp in front of the soundcard to make the best use of its available bits, but it is generally not a big deal (unless the opposite situation exist, where the input signal is so high it clips).

Be aware that many Creative cards do nasty compression and limiting in the upper 3dB or their range. With these you don't want your input to get close to that process. -6dB maximum peaks are often recommended.
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IveyLeaguer
post Nov 15 2006, 04:43
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I prefer to use audio restoration software to eliminate all kinds of noise and enhance the sound if it needs it. I use DiamondCut and will not use anything else. This is touchy stuff and it takes time and a very good ear to learn what you are doing but the results are well worth it.

But I would never touch your original rip, especially if it's vinyl. Save it lossless and work with a copy. The secret is to get a clean file, that is, as free of hiss, pops, clicks, etc. as you possibly can without compromising the audio, and make a never-to-be touched, lossless copy of THAT. Keep the original rip and the clean original in a safe place and from there you can apply equalizers, amplifiers, or other audio filters to as many cleaned files as you like. Once you are happy with them, NORMALIZE THOSE for play, probably with Replay Gain.

Once you get better at it, and you will, you can go back and copy the clean original and enhance the sound in a different or better way, if you like. This way your audio recordings are never compromised and best of all, you never have to worry about them.

smile.gif

This post has been edited by IveyLeaguer: Nov 15 2006, 04:44
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IveyLeaguer
post Nov 15 2006, 04:55
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QUOTE (AndyH-ha @ Nov 14 2006, 18:38) *
Be aware that many Creative cards do nasty compression and limiting in the upper 3dB or their range. With these you don't want your input to get close to that process. -6dB maximum peaks are often recommended.


The sound card does make a difference, and is critical when recording. I replaced my Creative card with an inexpensive, but much QUIETer card, which is great for recording, but not as good for playback. There are some great all-round cards for audio out there and I'll be looking for one soon.

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2Bdecided
post Nov 15 2006, 13:29
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QUOTE (macchipazzi @ Nov 14 2006, 20:05) *
if so, then is wav normalization only lossy in the fact that it's irreversible, or does sound quality actually get deteriorated? i would love to be able to normalize lossless formats losslessly, so i don't have to convert all my lossless ripped vinyls to mp3 just so i can gain them and listen to them on my computer. i'd like to actually be able to listen to the lossless versions without having to crank my speakers to the max.


So you don't want to normalise the .wav files because it's "lossy", so instead you convert to a lossy audio format, and losslessly change the gain on those.

You do realise that mp3 encoding is about 1000 times more lossy than changing the gain of a wavefile?

As Andy says, no one worries about the "losses" introduce by changing the gain of a 16-bit file when the source is vinyl.

As others have said, if the recording level is way too low, then there have already been losses during recording - but it's better to be 6dB too low than 1dB too high! If you record from vinyl, and it peaks at -6dBFS, it will sound very quiet compared to a current pop CD but I would say the recording level is OK. Also, you'll never get it to sound as loud as a current pop CD, for reasons other people have mentioned. You could ReplayGain everything, but then I would say that wouldn't I?

Cheers,
David.
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macchipazzi
post Nov 15 2006, 13:46
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ppp

This post has been edited by macchipazzi: Apr 1 2008, 19:24
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AndyH-ha
post Nov 15 2006, 15:01
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QUOTE
so i'm sure normalizing from these unnaturally low levels will alter the sound undisirably no matter what.
Wrong, it will just be louder -- unless you are using really bad software. Why don't you simply do a few and listen to them instead of fretting about bad dreams?
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macchipazzi
post Nov 15 2006, 15:31
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ppp

This post has been edited by macchipazzi: Apr 1 2008, 19:23
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2Bdecided
post Nov 15 2006, 16:23
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But it sounds (from what you say) like your original .wavs are rubbish anyway - probably recorded without a correct pre-amp - so they lack the correct RIAA equalisation to make the overall frequency response flat and accurate, as well as the necessary gain. (hint: there is no reason a signal from an LP should hit your PC at such a dramatically different gain to that from a cassette tape, unless the correct pre-amp is absent, or you have purposely reduced the gain somewhere).

Rather than trying to carefully preserve bit-accurate copies of what you have now, you should probably delete them all, buy a half-decent sound card and pre-amp, and start all over again!

Harsh, but accurate I fear.

Cheers,
David.

P.S. you can hear what other people's recordings of vinyl sound like in some of the threads in the FAQ:
http://www.hydrogenaudio.org/forums/index....7516#entry74075

This post has been edited by 2Bdecided: Nov 15 2006, 16:24
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AndyH-ha
post Nov 16 2006, 11:09
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By bad dream I meant your mis-concepts about what you are working with. You are standing in mid air, you have no grounds under you. Your idea of preserving your recording without change is like a religious concept generated purely out of the fear of thunder. Of course, since it is yours, you can do whatever you like with it. Some people do very weird things with their life.

What if you put a mixer into your current recording setup so you get higher levels to the soundcard, and thus have no need to amplify the data post recording? How will the recorded result be any different than what you would have if you amplified your current recordings with software?
answer:
The signal to noise ratio will be a little better, but if your system isn't too abysmally low quality, since your source is vinyl, it will not be anything you can notice.

Furthermore, as I wrote earlier, if you make two, or any number of recordings from the same LP, with the same equipment, under the same conditions, each will be unique. You cannot get two that are identical. Which is the lossless you hope to preserve? What is so special about the recording in its original state? It doesn't make any sense to fret about it in the slightest.
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