DSD64, what is it and how to extract/convert

Posted by: bicela on 22 February 2015

Dear All,

 

sooner or later also this format will be read from (some) Naim streamers.

 

I kindly ask exactly was it is and how we can extract the tracks.

 

Today, for example, I got a ripped image (ISO) of "Bill Evans - Bill Evans At The Montreux Festival (1968)" with the intent to explore how extract .dsf tracks (64bit) without quality loss.

 

Well, I use XLD and the "only" thing I was able to do is to extract all tracks and save to .wav 32bit / 192kHz.

 

Listen such files to my actual system from USB was amazing! And is not yet the correct extraction to .dsf, who I can do that?

 

P.S. The USB the reproduction suffers of buffer problem. I will try later from the NAS.

Posted on: 22 February 2015 by sjbabbey

Try this:

 

http://www.audiocircle.com/index.php?topic=129913.0

 

Suggest you convert to .DSF rather than .DFF as .DSF has tagging support (mp3tag etc.)

Posted on: 22 February 2015 by bicela

Thank you! I will try.

 

Maybe I've done a mistake, I realise that DSD are native 24bit, so have not sense to transcode to 32bit. Have sense?

Posted on: 22 February 2015 by sjbabbey
Originally Posted by bicela:

Thank you! I will try.

 

Maybe I've done a mistake, I realise that DSD are native 24bit, so have not sense to transcode to 32bit. Have sense?

If I recall correctly, the DSD format is actually single bit. It is only when it is converted/transcoded that it becomes 24bit or 32bit. I guess it depends on what bit level your DAC can handle. 

Posted on: 22 February 2015 by bicela

Probably I'm wrong, sorry.

 

This means that extract tracks from ISO image to .dsf preserve the full quality.

 

And when needed to transcode (for non DSD streamers) it should be possible to do that till 32bit / 192kHz.

Posted on: 22 February 2015 by sjbabbey

Sorry bicela,

 

I don't yet have a DAC which can play native DSD (am waiting for the naim firmware update for my NDS) so I cannot give you an authoritive reply. However, I would suspect that the transcoding from DSD bitstream to PCM would depend on the transcoding settings of your UPnP server software.

Posted on: 22 February 2015 by bicela
Originally Posted by sjbabbey:

I don't yet have a DAC which can play native DSD (am waiting for the naim firmware update for my NDS) so I cannot give you an authoritive reply.

Don' worry sjbabbey, the program you suggest is amazing! Thank you again.

 

I also have not... 

 

272? Need to listen it... But from I'm will be anyway an upgrade (I use now Uniti2 with 250/2).

Posted on: 22 February 2015 by Simon-in-Suffolk
Originally Posted by sjbabbey:
Originally Posted by bicela:

Thank you! I will try.

 

Maybe I've done a mistake, I realise that DSD are native 24bit, so have not sense to transcode to 32bit. Have sense?

If I recall correctly, the DSD format is actually single bit. It is only when it is converted/transcoded that it becomes 24bit or 32bit. I guess it depends on what bit level your DAC can handle. 

actually DSD is equivalent to 16bit in PCM.

Simon

Posted on: 22 February 2015 by bicela

Thank you Simon, so one last question arise, if is needed to transcode, which is the good compromise keeping in mind the actual Naim capability? For SR I suppose the highest as possible? 192kHz?

Posted on: 22 February 2015 by Simon-in-Suffolk

This is a tricky one as one is not comparing like with like and converting DSD to PCM is potentially a lossy process Effectively by transcoding we are asking a PCM DAC to emulate a DSD DAC, and this will in my opinion require bandwidth to encode the DSD shaping as well as the original audio.

DSD64 when carried as DoP is sent as a 176.4/24 SPDIF stream. Each SPDIF 24 bit sample is converted and packetised in to a series of 16 x 1 bit samples plus an 8 bit control byte. The data is very different to PCM samples.

Thetefore  if transcoding to true PCM the sample rate and resolution is going to be governed by the resolution, quality and settings of your DSD/PCM conversion software and I would suggest at least not less than the DoP rate of 176.4/24.

Posted on: 23 February 2015 by Aleg
Originally Posted by Simon-in-Suffolk:

This is a tricky one as one is not comparing like with like and converting DSD to PCM is potentially a lossy process Effectively by transcoding we are asking a PCM DAC to emulate a DSD DAC, and this will in my opinion require bandwidth to encode the DSD shaping as well as the original audio.

DSD64 when carried as DoP is sent as a 176.4/24 SPDIF stream. Each SPDIF 24 bit sample is converted and packetised in to a series of 16 x 1 bit samples plus an 8 bit control byte. The data is very different to PCM samples.

Thetefore  if transcoding to true PCM the sample rate and resolution is going to be governed by the resolution, quality and settings of your DSD/PCM conversion software and I would suggest at least not less than the DoP rate of 176.4/24.

I agree with the explanation and recommendations by Simon.

 

Personally I nowadays go for 88.2kHz/24-bit when converting DSD64.

I feel 88.2 is sufficient as conversion software use a (steep or slow) roll-off filter anyhow, varying from 24kHz - 48/50kHz, but about 40kHz is considered sufficiently safe against high level noise and sufficiently wide to allow 'all' music data to be captured.

 

Nice read on the subject: http://archimago.blogspot.de/2...of-dsd-encoders.html

 

Cheers

 

Aleg

Posted on: 23 February 2015 by bicela

Thank you Simon and Aleg, grazie.

Posted on: 23 February 2015 by bicela

From Alex link and your all precious comments by forum members:

Remember that any conversion between DSD to PCM is a "lossy" process. Therefore, it is of course preferable to keep PCM sourced recordings in PCM and DSD likewise if possible. There will be some compromise in the accuracy each time conversion happens. Even though the bitrates for DSD64 and 24/96 PCM may be similar, the modulation technique used to represent the resultant sound wave is different. The question of course is how much difference and if it's quantifiable.

I'm wrong or ALL Naim products need to work on PCM as digital to analog process? If so lot of carefully needs to be used in DSD "lossy" conversion to PCM. Is this then the reason why only SHARC digital signal processors must be used, let less sophisticated streamers apart from compatibility upgrade to DSD support?

 

Exist a streamer that can do DSD to analog conversion without pass by a "lossy" PCM transcode? I suppose yes, because we have SACD readers with analog exit, but I don't know how.

 

I'm sorry if I have oversimplified.

Posted on: 23 February 2015 by Simon-in-Suffolk

i wouldn't worry... but my view is

 

Accurate digital  to analogue conversion requires typically two key digital components

  1. Digital filtering or reconstruction filtering 
  2. Single or multibit digital to analogue converter.

So

  • Irrespective  of 2), step 1) is required for where the digital audio is multibit sample (PCM) or single bit (DSD)
  • Irrespective of the audio data type processed in 1),  step 2) can be a mutibit converter ( as used by Naim) or a single bit delta sigma converter.

Therefore the ability to play either DSD or PCM requires a quality integration between 1) and 2). Further the actual physical conversion technique need not be governed by the digital data audio source encoding method.

 

The bandwidth and precision between DSP and DAC ( ie 1 and 2 ) is usually greater and often significantly greater than the source audio bandwidth

 

Posted on: 24 February 2015 by bicela
Originally Posted by Simon-in-Suffolk:

The bandwidth and precision between DSP and DAC ( ie 1 and 2 ) is usually greater and often significantly greater than the source audio bandwidth

Thank you Simon, this clarify me that either PCM or DSD are solution to the same "problem".