Author Topic: High-Fi bitrate resampling in VinylStudio?  (Read 9603 times)

urs

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High-Fi bitrate resampling in VinylStudio?
« on: July 15, 2009, 11:28:17 am »
Hi there everybody

I was trying to find out if VinylStudio uses some kind of High Fidelity Resampling / interpolation Algorithms, when downsampling Bitrate and Sample Rate in order to get the recorded albums onto an Audio CD.

More concretely: I want to record my Vinyl Disks at the highest quality possible and bring the files to Audio CD. I do of course have a decent analog equipment and ADC for that.

In my experience with audio (and graphics, too), the best quality is usually achieved if recording is done at high bitrates and sample rates. If necessary, the editing (like filtering or "cleaning") should be done in that high resolution mode. The resampling "down" to Audio-CD-resolution is done just before burning the music to CD.

Precondition is, that the resampling process is done using high quality interpolation algorithms. I am not a technician, so I don't understand what that terms mean technically, but based on my user experience, a good Noise Shaping Dithering (e. g. as provided by Adobe Audition) gives the best results.

So let's say, I record at 96 khz / 24 bit.

Does VinylStudio interpolate those files in a decent quality using Noise Shaping? Or will I have to export the files and interpolate them with another software, such as Adobe Audition, before burning them to CD?

Does anyone have experiences regarding the recording technique in order to get Audio CDs at the best quality possible? Is there eventually a way to record directly at CD-samplerates in order to avoid resampling, and getting nevertheless a good output quality?

Is there eventually the possibility to use external programs like plug-ins within VinylStudio (such as for example SSRC for the sample rate conversion - I don't know that program, just read about it)?

Thank you for your help!

Best regards, Urs

Paul Sanders (AlpineSoft)

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Re: High-Fi bitrate resampling in VinylStudio?
« Reply #1 on: July 15, 2009, 03:01:10 pm »
Hi,

Yes, we use a high quality resampling algorithm, based on Julius O. Smith's resampling method which you will find described here:

http://www-ccrma.stanford.edu/~jos/resample/

I agree with you that using a decent resampling algorithm is essential.

If by noise shaping you mean dithering when reducing the bit depth, no we don't do that as we can get better perfomance without it.  We couldn't hear any difference in our own listening tests and we were also strongly influenced by these posts:

http://www.ethanwiner.com/dither.html
http://www.3daudioinc.com/3db/showthread.php?t=12836

It's also probably true that the noise floor of vinyl and tape recordings masks any effect dithering might have anyhow.

Sample rates: we were recently asked to support recording at 88.2kHz (i.e. CD samplerate x 2).  This would have the advantage that downsampling when burning CD's would just be a division by 2, which probably introduces fewer artefacts than odd ratios.  We will add this to VinylStudio when we have time.

Plugins: probably we won't do this.  VinylStudio is not really that kind of product, although if there is sufficient demand we may reconsider.

And finally: why don't you download a trial copy, make some recordings at, say, 96/24 and burn a couple of CD's (you can burn upto 5 tracks to any one CD in the trial version).  Let your ears be the judge.  I'd be interested to know what you think.

urs

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Re: High-Fi bitrate resampling in VinylStudio?
« Reply #2 on: July 15, 2009, 04:02:51 pm »
Hi there, thanks very much for that comprehensive answer! It reassures me. I will of course do hearing tests, as you suggest, as soon as I get the time to do it, and I will of let you know my findings. The 88,2-sampling-option seems very interesting to me. I wonder however if there is ADC-Hardware around that supports that - I am not sure for my device (E-MU 0404 USB, more musician's gadget, but it works quite will for vinyl2digital purposes, given there is a decent photo-stage available). Best regards!

Paul Sanders (AlpineSoft)

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Re: High-Fi bitrate resampling in VinylStudio?
« Reply #3 on: July 15, 2009, 04:23:28 pm »
I wonder however if there is ADC-Hardware around that supports [88.2 kHz]

Yes, good point, thank you.  Many, I suspect, do not, in which case VinylStudio's resampling algorithm is probably superior.  In particular, XP's resampling algorithm ('kmixer') is known to be poor; Vista's is much better.  Maybe offering 88.2 kHz recording is not such a good idea after all... The last thing you want is resampling going on behind your back at the recording stage.  I'll think it over.

jasustar

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Re: High-Fi bitrate resampling in VinylStudio?
« Reply #4 on: January 15, 2012, 08:20:40 pm »
I just switched to VinylStudio after using Audacity for quite a while. When using Audacity, I always sampled ay 96 kHz with a 32-bit float The results were spectacular. I switched to VinylStudio because of Scot hacker's glowing recommendation on his blog The Compleat Guide to Digitizing Your LP Collection . Since getting VinylStudio two days ago, I've been frequenting this forum and it seems the over whelming opinion is that 96 kHz with a 32-bit float is over kill for digitizing vinyl LPs. Could someone explain why this opinion is so prevalent? Or, could you point me to a post that discusses it? I've searched this forum quite a bit and haven't found an answer.

By the way, my recording set up is as follows:
  Turntable:       Denon DP-300F
  Cartridge:       Shure M97xE
  Software:       VinylStudio v8.2.2
  Computer:   Mac mini
  Model Identifier:   Macmini3,1
  Processor Name:   Intel Core 2 Duo
  Processor Speed:   2 GHz
  Number of Processors:   1
  Total Number of Cores:   2
  L2 Cache:   3 MB
  Memory:   4 GB
  Bus Speed:   1.07 GHz
  Boot ROM Version:   MM31.0081.B06
  SMC Version (system):   1.35f0
  

« Last Edit: January 15, 2012, 08:36:13 pm by jasustar »
John Schuster
jasustar@yahoo.com

Paul Sanders (AlpineSoft)

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Re: High-Fi bitrate resampling in VinylStudio?
« Reply #5 on: January 15, 2012, 08:41:17 pm »
Hi,

I would ask this question at Hydrogen Audio.  Lots of opinions there :), but almost all audio hardware is limited to 24 bit (or less), so using 32 bits gets you nothing extra.

Internally, VinylStudio works entirely in 32 bit floats, regardless of the format you record to (or save your tracks in).  This provides some 'headroom' for the various processing algorithms that we use.  When tracks are saved, these 32 bit floats are converted to the file format of the output file (this is the last step in the process).

Use the 'Sample Rates' button in VinylStudio's Check Level dialog to see what sample rates and bit depths your Mac supports.  Upto 96/24 is common nowadays.