Author Topic: Click Removal - DSD files  (Read 5441 times)

dtc

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Click Removal - DSD files
« on: October 30, 2014, 02:57:38 pm »
I have somewhat beat up recording in 2x DSD format. I did click removal on it and it sounds quite good. I have to save it as PCM to keep click removal, in flac.  When I save tracks using the default (As Recorded) it converts to 24/192. Given that 24/176 is an integer multiple of 5.6 MHz, I tried saving it at that resolution. I actually thought that As Recorded would go to 176 by default, as DSD is a direct multiple of 176.  It seems that when converting to 176 the click removal does not get applied. There is still a lot of noise. I can certainly use 24/192 but I wanted to ask if there is a problem with click removal when converting DSD to formats other than 24/192.

Second question, when upsampling and downsampling PCM, the norm is to do an integer conversion. That is 44 to 176 and 48 to 192, or vice versa,  partially for speed of conversion and partly to maintain the original data points in the data. Is there any similar advantage when converting  DSD to PCM? That is, is there any reason to go from DSD to 176 rather than to 192?

Thanks.

Paul Sanders (AlpineSoft)

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Re: Click Removal - DSD files
« Reply #1 on: October 30, 2014, 03:11:29 pm »
Hi,

You should be OK saving your declicked DSD as 176 kHz PCM.  Perhaps you could email me a short sound sample (about 15 seconds) so that I can hear what you hear.  Please send it to:

p DOT sanders AT alpinesoft DOT co DOT uk

Thanks.

As for saving at 192 kHz PCM, the 'true' samplerate of double rate DSD is not 176 kHz but 5.632 Mhz, using one-bit samples.  It doesn't really matter much what samplerate you convert this to when converting to PCM.  We chose 192 kHz as being a reasonable rate to preserve the fidelity of the original.

dtc

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Re: Click Removal - DSD files
« Reply #2 on: October 30, 2014, 03:26:24 pm »
Thanks for the quick reply. How do I cut out a 15 second sample?   GOT IT - Save Track As. Will do.

I understand that double DSD is 5.632 MHz. Just wondered if converting it to a integer multiple of that, like 176.4 KHz, made any difference. It sounds like say it does not. I was trying to keep it as 176 to keep it as an integral multiple, that's all.
« Last Edit: October 30, 2014, 03:32:28 pm by dtc »

Paul Sanders (AlpineSoft)

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Re: Click Removal - DSD files
« Reply #3 on: October 30, 2014, 03:34:49 pm »
Hi,

I think it's far enough removed that it doesn't much matter.  We chose 192 as being more likely to be natively supported by more sound cards.

To create a 15 second sample:

1.  Go to the Cleanup Audio window.

2.  Select about 15 seconds' worth of audio (click and drag in the waveform display).

3.  Right-click (or on the Mac, ctrl+click) and select 'Save Selection As.

4.  Select your file options if necessary and then click Save.

5.  Email me the resulting file.

dtc

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Re: Click Removal - DSD files
« Reply #4 on: October 30, 2014, 03:51:24 pm »
Go it, thanks. I did a Save Track As with a new track, but Save Selection As is the best way. Did not know about that one. Files have been sent.

Paul Sanders (AlpineSoft)

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Re: Click Removal - DSD files
« Reply #5 on: October 30, 2014, 08:28:30 pm »
Got the files, than you.  Yes, thinking about this, I realise it is an issue with the declicker.  A flaw in my thinking has been translated into the code.  I'm not sure we can fix this, but I'll take a look.  In the meantime, please save declicked files at 192 kHz.

dtc

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Re: Click Removal - DSD files
« Reply #6 on: October 30, 2014, 09:06:44 pm »
Thanks for the quick follow-up. Since 24/192 works fine, I will stick with that. I am trying to keep most of the files in DSD, but this one needed serious declicking. I should probably just start with PCM for the noisy albums, although the 24/192 conversions sound great.  Thanks again.

Paul Sanders (AlpineSoft)

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Re: Click Removal - DSD files
« Reply #7 on: October 30, 2014, 09:22:06 pm »
Thank you.  We will in fact fix this, at the cost of two sample rate conversions when click repairs exist.  So, best advice will still be stick with 192.