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"Bit-perfect" DSD output with gain in Korg AudioGate
tahaa7
post Nov 21 2011, 22:36
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Hi everyone,

Just a quick question: if I set a gain (negative), say -3dB in Korg AudioGate while playing a .dff file, will the output still be "bit-perfect" (or of the same quality, if you will) or will AudioGate degrade the signal quality because of the gain?

The reason I'm asking this is because with the gain set to 0, I get clipping at the output. At first, I assumed this was due to bad mastering and compression, but apparently with the DSD-to-PCM conversion, this may not be the only reason, due to the sheer nature of the DSD recording.

Thanks.

P.S.: I'm using an ASIO driver. AudioGate is set to PCM sampling rate of 192kHz.

This post has been edited by tahaa7: Nov 21 2011, 22:42
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Wombat
post Nov 21 2011, 23:05
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As i understand this you never had "Bit-Perfect" output. Applying a gain of any kind shouldnīt be a problem at all. The main problem will be how Korg translates the DSD data to PCM.
Normaly DSD should be mastered more silent so if it clips i wonder if Korg already applies a gain.

This post has been edited by db1989: Nov 22 2011, 11:43
Reason for edit: removing unnecessary full quote of above post
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DVDdoug
post Nov 21 2011, 23:31
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I don't know why you're getting clipping... If the PCM is clipped and the DSD is not, the conversion is obviously not bit perfect.

QUOTE
say -3dB in Korg AudioGate while playing a .dff file, will the output still be "bit-perfect"
Well... If you digitally reduce the volume, you are altering the bits... And, something similar happens with an analog volume control, so I wouldn't worry about it...

I'm not DSD expert, but I don't think bit perfect DSD to PCM is possible. (I think if you convert from DSD to PCM and then back to DSD, the new DSD data will be different.)

This post has been edited by DVDdoug: Nov 21 2011, 23:34
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tahaa7
post Nov 21 2011, 23:46
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Right. So the gain should be no problem.. Thanks guys.

Yeah, I know I can never get "bit-perfect" DSD audio since I don't have a DSD chip on my sound card. What I meant was audio of the same quality or about the same quality (since 192kHz is already a very high sampling rate)... Regarding the AudioGate, they say it is probably the best (or among the very best) DSD-to-PCM converter, so I have no reason to believe the output is not very accurate.

Regarding the gain: yes, the question remains whether AudioGate applies a gain by default when doing DSD-to-PCM conversion and if that is the reason for the clipping. I guess there's no way to tell for sure...

This post has been edited by db1989: Nov 22 2011, 11:44
Reason for edit: removing unnecessary quotes of two prior posts
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Wombat
post Nov 21 2011, 23:49
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QUOTE (DVDdoug @ Nov 22 2011, 00:31) *
I'm not DSD expert, but I don't think bit perfect DSD to PCM is possible. (I think if you convert from DSD to PCM and then back to DSD, the new DSD data will be different.)

We have a nice thread here http://www.hydrogenaudio.org/forums/index....=37717&st=0
It isnīt possible to translate DSD losslessly to PCM. The nearest approach will be to transalte digital values present in DSD to values in PCM with some kind of Matrix. The higher the PCM resolution the more precise.
24bit/352.8kHz seems the value that can perfectly represent all DSD noise smile.gif
You can create PCM version from there on to anything that is usable to you. You should handle this like downsampling any other PCM material.
24bit/88.2kHz with an early lowpass should preserve anything recorded in the DSD data. More bandwith only translates to more useless noise imho. So Korg already has the wrong approach, it allows lots of aliasing with preserving tons of noise and only using very gentle filters.

Edit: in the userguide to Audiogate they claim 1-bit audio may exceed the limits of PCM so you should apply -3dB on converting. Strange, i understood it differently. Maybe someone more experienced can help. Also i rechecked and they use a "Sharp" lowpass with -3db at 42kHz. Another strange value that makes no sense for me besides looking good on a spectral view.

This post has been edited by Wombat: Nov 22 2011, 00:22
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RandyOsbourne
post Feb 12 2012, 04:20
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I've always used Weiss Saracon DSD to PCM with No gain. If you then analyze the files with foobar's DR meter most all SACD files need added gain afterword.
Then take foobars reading of the highest peak of all files L & R channels and subtract .10db from that to add as Album gain again with Weiss Saracon...

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Wombat
post Feb 12 2012, 04:37
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QUOTE (RandyOsbourne @ Feb 12 2012, 04:20) *
I've always used Weiss Saracon DSD to PCM with No gain. If you then analyze the files with foobar's DR meter most all SACD files need added gain afterword.

And this helps us in what way here? So some still clip? You can of cause just use a negatiive gain with Korg and calculate the maximum gain to use from that. Besides that Saracon if used legaly isnīt exactly a bargain.

This post has been edited by Wombat: Feb 12 2012, 04:40
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RandyOsbourne
post Feb 26 2012, 13:54
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QUOTE (Wombat @ Feb 11 2012, 22:37) *
QUOTE (RandyOsbourne @ Feb 12 2012, 04:20) *
I've always used Weiss Saracon DSD to PCM with No gain. If you then analyze the files with foobar's DR meter most all SACD files need added gain afterword.

And this helps us in what way here? So some still clip? You can of cause just use a negatiive gain with Korg and calculate the maximum gain to use from that. Besides that Saracon if used legaly isnīt exactly a bargain.

None clip cause they are always around -2db to -6db negative from 0db when converting from DSD to PCM with Weiss Saracon and no gain...
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