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Topic: What's the ideal way to fix the pitch of a vinyl recording? (Read 1719 times) previous topic - next topic
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What's the ideal way to fix the pitch of a vinyl recording?

I have a few lossless vinyl recordings that were unfortunately done with the pitch setting (think +/-8% setting on an SL-1200) not at the 0 position. If I can determine the amount by which the recordings were sped up (lets say they were recorded with the pitch setting at max, ie +8%), what's the best way to edit them to the correct pitch? The goal is to preserve the quality as much as possible. I assume such simple slowing down doesn't have the same undesirable impact on the audio material as pitch shifting or time stretching and it's transparent enough that it's worth doing the intended edits.

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #1 –
Quote from: drumliner on
I have a few lossless vinyl recordings that were unfortunately done with the pitch setting (think +/-8% setting on an SL-1200) not at the 0 position. If I can determine the amount by which the recordings were sped up (lets say they were recorded with the pitch setting at max, ie +8%), what's the best way to edit them to the correct pitch? The goal is to preserve the quality as much as possible. I assume such simple slowing down doesn't have the same undesirable impact on the audio material as pitch shifting or time stretching and it's transparent enough that it's worth doing the intended edits.

I believe you can do this in Audacity. I KNOW you can do this in Adobe Audition. The result is exactly the same as turning the pitch control on the turntable. BTW, what is "lossless vinyl"?

G²
 

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #2 –
If you're saying the original vinyl was spinning at the wrong rate, then what you need is to correct the speed (the alternatives being tempo and pitch).  Speed control alters the playback time of the track, with the pitch altering accordingly (as it would if you alter the speed of a deck).

Changing the speed is a process of resampling, and has practically no impact on the quality of the audio.  Tempo control (which changes the BPM of the track without altering the pitch) and pitch control (which does the reverse) both require significant processing, with acoustic artefacts which get worse the greater the adjustment.

All three (speed, tempo, pitch) can be achieved in FB2K, but I recommend Audacity.  If you did want to alter pitch or tempo, it has a very good non-real-time processor (if you tick the "high quality" box).
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #3 –
to be really sure you're doing this the right way, better stick to using only resampling.

it requires a step where you change the sample rate without resampling (to actually change the speed), this is rarely implemented but when it's in WAV/PCM format, it has a fairly simple structure so you can edit the sample rate number in the header with a hex editor.

resampling is even optional, if you don't care that the resulting sample rate will be something wildly non-standard. Most players will resample on the fly. And it's the most lossless method, if all you do is modify one number in the file header without even changing the waveform data.

so, for example: let's say you have a record in 44.1 kHz and you need to make it play twice as fast (and therefore also an octave higher). Then you can edit the sample rate info in the header to be 88.2 kHz, and that's it.
a fan of AutoEq + Meier Crossfeed

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #4 –
First a big thanks to everyone for responding, now on to your replies...

Quote from: Glenn Gundlach on
I believe you can do this in Audacity. I KNOW you can do this in Adobe Audition. The result is exactly the same as turning the pitch control on the turntable. BTW, what is "lossless vinyl"?

Many audio editors will let you do it and I am asking about the best way to go about this in order to maintain audio quality as much as possible, ie not unnecessarily introduce anything unwanted in the process. As for your question I said "lossless vinyl recordings", meaning recordings of vinyl stored in a lossless format to point out these aren't lossy files editing of which would lead to loss of quality anyway, making my question about retaining quality largely moot. Apologies for the confusion.


Quote from: fooball on
If you're saying the original vinyl was spinning at the wrong rate...

Yes that's what I meant. I'm familiar with the audio editing processes and I was trying to avoid confusion with my choice of words, but I guess I wasn't all that successful at that. I'm used to "time stretching"  as the process of changing tempo without altering the pitch and "pitch shifting" as the process of changing pitch without altering the tempo and I know these two will mess with audio quality, although they have certainly progressed a fair bit compared to the early days. In any case I'm not trying to do either of these, all I need is to simply slow down the recordings to avoid re-rerecording the vinyls at the right speed (I determined all the problematic vinyls have been recorded at +8%). I used "pitch" in the thread's title because that's what the control for changing the speed at which the vinyl is spinning is usually labeled on turntables like the famous Technics and I thought people would be most familiar with this terminology when talking about vinyl. Again sorry for the confusion.

Quote from: magicgoose on
to be really sure you're doing this the right way, better stick to using only resampling.

it requires a step where you change the sample rate without resampling (to actually change the speed), this is rarely implemented but when it's in WAV/PCM format, it has a fairly simple structure so you can edit the sample rate number in the header with a hex editor.

resampling is even optional, if you don't care that the resulting sample rate will be something wildly non-standard. Most players will resample on the fly. And it's the most lossless method, if all you do is modify one number in the file header without even changing the waveform data.

so, for example: let's say you have a record in 44.1 kHz and you need to make it play twice as fast (and therefore also an octave higher). Then you can edit the sample rate info in the header to be 88.2 kHz, and that's it.

This is exactly what I'm trying to do. The recording was done at 96khz with the "pitch" setting on the turntable at +8%, so I need to slow down by roughly 7.41%, which if my calculations are still correct, would be the same as setting the sample rate to 88.886hz (no resampling as you say). My audio editor allows me set the sample rate directly (has a "set sample rate only, no resampling" option), so I don't even have to hex edit the header manually. But I do think I'd rather have a standard sample rate, so I guess I can then resample from 88.886hz to the standard 44.1khz. Would this be fine or am I messing up somewhere?

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #5 –
I still say resample in Audacity (or whatever audio editor you like), it will be simpler in the long run.  Keeping to a standard sample rate will be compatible with more players, and the resampling will not be audible.  There are far greater distortions in the extraction of audio from vinyl.

What you might not realise is that unless you take special measures, the player will resample to its default sample rate anyway, that's how multiple audio sources can be mixed together to get (say) a system alert with a music source and/or a video track simultaneously.  Resampling is all over the place whether you like it or not.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #6 –
You are very close to the standard sampling rate of 88.2, so you might of course try that and listen if the small difference is any audible.

For resampling, you need to use a tool that guards against clipping. But if this is straight from the recording, it seriously shouldn't be close to full range anyway. (What are the peaks?)

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #7 –
Quote from: fooball on
I still say resample in Audacity (or whatever audio editor you like), it will be simpler in the long run.
I agree. My goal was to have the fixed files at 44.1khz since resampling is always going to occur at some point anyway with a non-standard sample rate, so might as well do that with full control as opposed to leaving it to the playback chain and hoping for the best. Just gotta pick the best way/tool to do the resampling as they're not all equally good (looking at this resampler comparison https://src.infinitewave.ca).

Quote from: Porcus on
You are very close to the standard sampling rate of 88.2, so you might of course try that and listen if the small difference is any audible.

For resampling, you need to use a tool that guards against clipping. But if this is straight from the recording, it seriously shouldn't be close to full range anyway. (What are the peaks?)

I tried it and I would say I do notice the slight difference in pitch between resampling to 88.2 as opposed to the calculated 88.886, although I guess I should have done a proper blind test to absolutely confirm I wasn't just fooling myself. Might still go with 88.2 anyway since noticing the difference against a comparison is a lot easier than noticing something's off when listening to it in isolation (unlike the current +8% difference that I easily notice in isolation which is why I want to fix it). Unfortunately the files were already normalized to 0db and so a handful of peaks have no headroom left. What tool and procedure would you recommend for resampling?

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #8 –
I really don't see that Audacity gives you anything to complain about, and I imagine your personal favourite DAW would be the same.  Just do what's convenient, and check the peaks on the product before committing (just a case of reducing the amplitude before resampling, if necessary).

Any resampling artefacts will be buried in the noise.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #9 –
If they are normalized to 0 dB ... I suggest reducing by 3 dB and asking for a report about clips. Likely there won't be any.
You can safely reduce by much more. Six dB is (nearly) one bit, but if it is saved as 16 bits, the bottom few are surface noise anyway.

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #10 –
Quote
I really don't see that Audacity gives you anything to complain about, and I imagine your personal favourite DAW would be the same.  Just do what's convenient, and check the peaks on the product before committing (just a case of reducing the amplitude before resampling, if necessary).
Actually, since Audacity uses floating-point internally it can go over 0dB and it won't clip.   You can set Audacity to "Show Clipping" and it will show-read for potential clipping.  So, you'll be OK of you re-normalize after correcting the speed and before you export.    Or you can just re-normalize no matter what.

If you are paranoid about inter-sample-overs (I'm not) you can normalize to -1dB or so.   (Audacity's Normalize effect defaults to -1dB and Amplify defaults to 0dB peaks.)  
BTW- The effect you want to use is Change Speed.

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #12 –
Quote from: fooball on
I really don't see that Audacity gives you anything to complain about

Oh I wasn't trying to say there's anything wrong with Audacity in this respect (I do have an issue with its fade in/out process on 16bit files though). I just know that some resamplers can do a bit of a mess (as you can see on the site I linked) and since I not knowing any better used some of those in the past, I'm a bit more cautious now. That's all.

Quote from: Porcus on
If they are normalized to 0 dB ... I suggest reducing by 3 dB and asking for a report about clips. Likely there won't be any.
You can safely reduce by much more. Six dB is (nearly) one bit, but if it is saved as 16 bits, the bottom few are surface noise anyway.

The files are saved as 96khz / 24bits. Off topic tangent... with the sample rate / bit depth overkill, there's plenty of content recorded past the 20khz I'm toying with the idea of slowing it down into the audible range. Not to store as music of course, just to mess around with it to see if anything interesting pops out.

Quote from: DVDdoug on
Actually, since Audacity uses floating-point internally it can go over 0dB and it won't clip.
Thanks for the tips. I actually already tried this earlier today and noticed it doesn't clip. I got some overs after testing with some processing, re-normalized the file and checked its highest peaks, none of which were clipped.

Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #13 –
Quote
I just know that some resamplers can do a bit of a mess (as you can see on the site I linked) and since I not knowing any better used some of those in the past, I'm a bit more cautious now. That's all.
The Change Speed effect in Audacity is not "traditional" re-sampling.    It's just interpolating and you won't get aliasing.

...And some of those re-samplers that "look bad" don't necessarily sound bad.   Remember HydrogenAudio is all about what you can actually hear (the famous TOS #8).

Quote
there's plenty of content recorded past the 20khz I'm toying with the idea of slowing it down into the audible range. Not to store as music of course, just to mess around with it to see if anything interesting pops out.
I don't know what's "interesting" but ultrasonic (and subsonic) frequencies will either have no effect on the sound or they "cause trouble".   Generally, they should be filtered-out if possible.    Ultrasonics are usually weak and the RIAA EQ lowers the highest frequencies so the high frequency noise from records usually isn't a problem.    Subsonic frequencies from records are usually from record warp or rumble.    They can be strong and they tend to cause more trouble.



Re: What's the ideal way to fix the pitch of a vinyl recording?

Reply #14 –
Quote from: DVDdoug on
The Change Speed effect in Audacity is not "traditional" re-sampling.    It's just interpolating and you won't get aliasing.

...And some of those re-samplers that "look bad" don't necessarily sound bad.   Remember HydrogenAudio is all about what you can actually hear (the famous TOS #8).
I fully agree and completely respect TOS #8. It's just that I sometimes heavily process audio (not the music stored for just listening of course) and so I prefer not to introduce "garbage" even if it's below the hearing threshold in normal circumstances, because it might jump above it after processing. Easier to prevent beforehand, than try to fix afterwards, right?

Quote
I don't know what's "interesting" but ultrasonic (and subsonic) frequencies will either have no effect on the sound or they "cause trouble".   Generally, they should be filtered-out if possible.    Ultrasonics are usually weak and the RIAA EQ lowers the highest frequencies so the high frequency noise from records usually isn't a problem.    Subsonic frequencies from records are usually from record warp or rumble.    They can be strong and they tend to cause more trouble.

Definitely not interesting as part of the music I recorded and I'm fully on board with "filter out if possible" in that regard, I meant it for a creative purpose, hence the "off topic tangent" label. I would expect that the actual music which sits in the hearing range has made an imprint, so to speak, on its ultrasonics which therefor aren't just purely random noise (although even that could be interesting, see noise generators on synthesizers). If so and with appropriate, heavy if necessary, processing, I might get out some interesting textures and rhythmical grooves that I could use in a project. That's the interesting bit for me, naturally not for everyone.