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Topic: recording vinyl at high sample rate (Read 5727 times) previous topic - next topic
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recording vinyl at high sample rate

Hi, I need some help on recording vinyl to PC for repairs re. recording at high sample rates.

Checked the HA wiki on Vinyl recording, it said: "This does not preclude using higher sample rates if there is a clear objective reason to do so".

I'm doing repairs using Cool Edit -- my assumption (perhaps wrong) is that if you have more samples then when it comes to declicking I'm giving Cool Edit a better chance to be more precise and not remove too many surrounding samples.

Is this a clear objective reason, or have I missed something?

Also I remember reading in some blog that if you were going to later down-sample to 44100 then it's better to record at 88200. I think I see the logic, but is that sensible?

Lastly, I was going to record at 16bit, -- I'm not looking to alter the EQ of the original material or do any thing too fancy -- it's more surgery than re-mastering, should I stick to 16bit?

Any help very much appreciated!

Rachel.
PC = TAK + LossyWAV  ::  Portable = Opus (130)

recording vinyl at high sample rate

Reply #1 –
I would say yes to all three questions. Higher sample rate could be helpful in declicking, and at worst couldn't hurt, 88200 is preferable if you are aiming for 44100, and in processing vinyl 16 bit should be adequate, as long as the original recording uses as much as possible of the dynamic range without clipping.

recording vinyl at high sample rate

Reply #2 –
You're gonna have to actually test that hypothesis out (higher sample rates work better for declicking) if you buy it

I put that statement into the wiki as a catchall. A more accurate statement would be, "don't record at higher than 44.1 unless you have a very good reason to do so." Generally, there are no good reasons to record higher than 44.1, as long as you believe that ultrasonics are inaudible.

If declicking does work better at higher rates, it would be a good reason. But in the absence of additional information, the energy content of most pops and clicks is generally attenuated at high frequencies anyway, at least if you're using RIAA eq in your preamp. So you're not losing a whole lot of pop energy by using a lower sampling rate. And that energy is that helps the declicker work.

If you have a CD-4 LP, and are decoding it in software, it is absolutely essential that you record to at least 96khz. But by and large, this situation doesn't exist. I'm not aware of a software CD-4 decoder.

If the ultrasonic harmonic distortion of the record playback is audible, then it may be important to capture it in the recording in order to reproduce it later. But it's not. So don't.

recording vinyl at high sample rate

Reply #3 –
As discussed in another thread recently, my experiments did not find any benefit what-so-ever of higher sample rates for declicking or noise reduction. I suppose there might be something I missed in that, finding no differences, I abandoned the experiments after a few trials. Regardless, it is silly to fret over it. Try it both ways and see if you can find any difference.

If you are going to be processing in CoolEdit, there is much more potential benefit in recording to 32 bit float and resampling to 16 bit only as the very last step. This is objective and certain. The quantization errors are only 1/65536 as large.

recording vinyl at high sample rate

Reply #4 –
Quote from: AndyH-ha on
If you are going to be processing in CoolEdit, there is much more potential benefit in recording to 32 bit float and resampling to 16 bit only as the very last step. This is objective and certain. The quantization errors are only 1/65536 as large.


Thanks that's very helpful.
Thanks to the others too.


I did a search but didn't find your post. -- I'll look again.

R.
PC = TAK + LossyWAV  ::  Portable = Opus (130)

recording vinyl at high sample rate

Reply #5 –
Quote from: carpman on
I'm doing repairs using Cool Edit -- my assumption (perhaps wrong) is that if you have more samples then when it comes to declicking I'm giving Cool Edit a better chance to be more precise and not remove too many surrounding samples.

The process of declicking involves replacing enough samples to span the full extent of the click. If you sample at twice the rate, the click will extend over twice the number of samples. So there is really no difference in end result.

Quote from: carpman on
Also I remember reading in some blog that if you were going to later down-sample to 44100 then it's better to record at 88200. I think I see the logic, but is that sensible?

It doesn't matter whether you're downsampling from 88.2kHz or 96 kHz, you still have to apply a low pass filter first. After that, discarding every other sample (88.2->44.1) is of course programmatically easier than recalculating the required samples (96->44.1), but mathematically the two processes are pretty much the same.

Quote from: carpman on
Lastly, I was going to record at 16bit, -- I'm not looking to alter the EQ of the original material or do any thing too fancy -- it's more surgery than re-mastering, should I stick to 16bit?

As Andy has pointed out, using greater bit depths means any quantisation rounding errors are minimised. But when the source is LP, the surface noise from the vinyl is massively greater than the 16 bit quantisation error level. You'd have to do a huge amount of processing before the rounding errors built up sufficiently to be noticable.

On the other hand, audio restoration is not a straightforward process, and having access to as wide a variety of tools is useful. There are some useful tools around that only work at 16 bit. If you work at 24 or 32 bit, you deny yourself the chance of using those tools. For that reason I would recommend that you stick to 16 bit. But if you are planning to use CoolEdit exclusively, then it's probably sensible to use 32 bit float for maximum peace of mind.

recording vinyl at high sample rate

Reply #6 –
My response about bit depth was mainly to point out that your assumptions were backwards. Higher sample rates make no difference for music, greater bit depths do. If you were making quality live recordings in a good environment, using 24 bit would be a no brainer. Although there are arguments to the contrary about sample rates, they remain purely subjective, unverifiable by any objective listening tests. As cliveb pointed out, with LP transfers the differences between 16 and 24 bit, while real, are not very likely to be audible.

If you work in 16 bit in CoolEdit, I suggest you turn off "dither transform results" under settings (this applies only to 16 bit). The dither is unnecessary due to LPs high background noise and, more importantly, the dither applied is not noise shaped. Normally, dither is itself inaudible, but do enough transforms with this and the dither noise becomes quite noticeable.

recording vinyl at high sample rate

Reply #7 –
Quote
If you have a CD-4 LP, and are decoding it in software, it is absolutely essential that you record to at least 96khz. But by and large, this situation doesn't exist. I'm not aware of a software CD-4 decoder.

For my education, what the heck is a CD-4 LP? 

recording vinyl at high sample rate

Reply #8 –
It's a flavor of quadraphonic.

recording vinyl at high sample rate

Reply #9 –
Quote from: AndyH-ha on
My response about bit depth was mainly to point out that your assumptions were backwards. Higher sample rates make no difference for music, greater bit depths do. If you were making quality live recordings in a good environment, using 24 bit would be a no brainer. Although there are arguments to the contrary about sample rates, they remain purely subjective, unverifiable by any objective listening tests. As cliveb pointed out, with LP transfers the differences between 16 and 24 bit, while real, are not very likely to be audible.


Yes. I see that my assumptions related to a) the Hz range of the audio itself and b) the Hz of the sample rate were getting all jumbled and confusing me. Thanks for all the feedback --- it made me go away and look at it all again.

By the way. along the way I came across this analysis of Vinyl v. EAC Ripped CD v. CD
Thought it was pretty interesting.

http://www.audioholics.com/education/audio...s-vs-cds-part-4

Thanks.
Rachel
PC = TAK + LossyWAV  ::  Portable = Opus (130)

recording vinyl at high sample rate

Reply #11 –
She has other theories which she explained in an email to me. Something about the added distortion of LP acting a bit like a dynamic range expander - making the louder parts even louder. This distortion could be perceived as "better" than the original, and possibly closer to the original sound if the master includes dynamic range compression.

I still think she clings onto unrealistic ideas about CD being inferior to LP. Any additional HF content is distorted, inaudible, and so irrelevant IMO. Any in-band distortions and noise and other effects (there's echo too) can be easily captured by copying the LP onto CD, if you so wish.

Cheers,
David.