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Chord Hugo - Page 128

post #1906 of 14306

Rob,

How difficult is it, during coding of the FPGA, and especially the filters, to get both DSD and PCM right?  Is this a challenge vs creating the best sounding DAC for one or the other?  DSD seems more analog (i.e no real samples, just bit to bit differential per se) in its structure so it would seem that they are quite different animals to design for.

 

As I said in my Qute HD review on CA, I was a DSD-aholic until I heard what the Qute series (now own an EX) does for any PCM, including redbook.  It's DSD is very good too (I think EX's DSD is better than HD but maybe just more break-in) but no longer really care that much about formats, as anything you throw at it is quite musical.

post #1907 of 14306
Quote:
Originally Posted by Hifi Nutter View Post

cheers mate let me know

 

my contact is not in today but I have been reliably informed they are available to buy... looks like Custom-Cable have them in stock:

 

http://www.custom-cable.co.uk/hifi-cables/custom-cables/chord-cable-company/

post #1908 of 14306
Quote:
Originally Posted by Rob Watts View Post
 

Yes. But saying it's a delta sigma hides an awful lot of sins - it can go from awful to astounding depending upon a huge number of factors, the largest of these being the oversampling rate. For example, going from 64FS to 2048FS produces a huge change in performance - and that is just one example. I have been working with noise shapers for 20 years and I am still discovering ways of improving the sound.   

 

I agree with you.  Guess my slightly OCD nature of needing to put everything into a box whether they want to be in it or not.  Oftentimes audio starts to verge of the snake oil and oftentimes I am not able to personally audition all the equipment that needs to be auditioned.  So I like to understand the basic design and whether or not I think it will make a difference and that helps me to decide which equipment to audition/buy.  Of course, obsessively reading forums like this and hearing the scuttlebutt is another way.  Both methods work, but it is better when they both agree.

post #1909 of 14306
Quote:
Originally Posted by ted_b View Post
 

Rob,

How difficult is it, during coding of the FPGA, and especially the filters, to get both DSD and PCM right?  Is this a challenge vs creating the best sounding DAC for one or the other?  DSD seems more analog (i.e no real samples, just bit to bit differential per se) in its structure so it would seem that they are quite different animals to design for.

 

As I said in my Qute HD review on CA, I was a DSD-aholic until I heard what the Qute series (now own an EX) does for any PCM, including redbook.  It's DSD is very good too (I think EX's DSD is better than HD but maybe just more break-in) but no longer really care that much about formats, as anything you throw at it is quite musical.

Hmm. Not an easy question to answer. Firstly an explanation of the pros/cons of the formats:

 

1. PCM Pro: excellent resolution of small signals, very small signals do not disappear into the dithered noise floor.

    Cons: Timing. Ear/brain can resolve 4uS, CD innately is at 22uS.

2. DSD Pro: Samples at 0.34 uS, albeit at not very good resolution, so has much better timing innately

    Cons: resolution. Noise shaper noise is not the same as dithered noise, any signal below noise shaper noise floor is lost.

 

Now the timing issue can be resolved by the DAC interpolation filter, and with an infinite tap length filter, timing is completely reconstructed. So red-book is capable of very much better performance, if you improve the interpolation filter. But with DSD, the encoding means that low-level details are lost in the noise shaper noise floor, and they are lost forever. So DSD has a compression in depth and instrument separation, due to poor resolution, but does not innately have timing problems. Check out 2L website, and compare the DXD recording to the DSD64 or DSD128 - to my ears, the loss in transparency of DSD is not small.

 

Getting back to design of the DAC. Now I run my DAC's with a very simple single stage active analogue section, with only 2 caps and 2 resistors in the direct signal path - and I do this for transparency. But this means the digital RF noise in the 100k to 1M band must be very low, so the digital source must be filtered - and DSD is at -20dBFS at 100kHz. So I can't put raw DSD into the DAC, or it will sound very hard. So the DSD is filtered, which converts it to regular PCM.

 

If I were doing a DAC for only DSD would I do it this way? Yes, I think I would, as simple analogue is always the best.

 

Incidentally, the DSD filters on Hugo has been improved - they are much smoother than with Qute.

post #1910 of 14306

So do I take from this that you are hearing that PCM is more transparent than DSD on quality recordings?

 

Part of the danger, IMO, of purchasing DSD is that a number of them have been created from PCM recordings, and this is true of a well respected firm that released a number of DSD recordings, so to know the true source is often the question. I have some true DSD recordings arriving in a few days. Here in the bush I can't download as I don't have the bandwidth to do this but can purchase them and get them sent to me. 


Edited by jamato8 - 4/16/14 at 7:38am
post #1911 of 14306
Quote:
Originally Posted by jamato8 View Post
 

So do I take from this that you are hearing that PCM is more transparent than DSD on quality recordings?

Yes. But.. I have heard awful DSD's compared to regular PCM, and awful PCM compared to DSD. So if the recording started as DSD, stick to DSD and vice versa.

 

The 2L website does allow us to hear DXD (352.8 kHz PCM the DSD master tape if you like) against DSD, and you can hear the losses that DSD gives. And if I were not using a DAC with a WTA filter, I guess I would prefer DSD every time. So like most things in life, it all depends! 

post #1912 of 14306
Quote:
Originally Posted by Rob Watts View Post

Hmm. Not an easy question to answer. Firstly an explanation of the pros/cons of the formats:

1. PCM Pro: excellent resolution of small signals, very small signals do not disappear into the dithered noise floor.
    Cons: Timing. Ear/brain can resolve 4uS, CD innately is at 22uS.
2. DSD Pro: Samples at 0.34 uS, albeit at not very good resolution, so has much better timing innately
    Cons: resolution. Noise shaper noise is not the same as dithered noise, any signal below noise shaper noise floor is lost.

Now the timing issue can be resolved by the DAC interpolation filter, and with an infinite tap length filter, timing is completely reconstructed. So red-book is capable of very much better performance, if you improve the interpolation filter. But with DSD, the encoding means that low-level details are lost in the noise shaper noise floor, and they are lost forever. So DSD has a compression in depth and instrument separation, due to poor resolution, but does not innately have timing problems. Check out 2L website, and compare the DXD recording to the DSD64 or DSD128 - to my ears, the loss in transparency of DSD is not small.

Getting back to design of the DAC. Now I run my DAC's with a very simple single stage active analogue section, with only 2 caps and 2 resistors in the direct signal path - and I do this for transparency. But this means the digital RF noise in the 100k to 1M band must be very low, so the digital source must be filtered - and DSD is at -20dBFS at 100kHz. So I can't put raw DSD into the DAC, or it will sound very hard. So the DSD is filtered, which converts it to regular PCM.

If I were doing a DAC for only DSD would I do it this way? Yes, I think I would, as simple analogue is always the best.

Incidentally, the DSD filters on Hugo has been improved - they are much smoother than with Qute.

Hi Rob,
With you talking about dsd versus pcm what setting should I have my onkyo hf player on,pcm or dop for best sound quality to the Hugo from my iPhone
post #1913 of 14306
Quote:
Originally Posted by Hifi Nutter View Post

Think I'll be buying the book DAC for dummies to join into these conversations,Christ I don't know what I've been doing with my life!

 

Tell me about it. Too many realms of knowledge are needed today to understand what is going on with the advent of digital.  Luckily for me, I have a fairly technical background, but even with some knowledge, often the underlying arguments get to too deep into the specifics to really understand what is going on.  But some basic understanding however helps you separate the chaff from the wheat.  The funny thing is that the basic methods and the inherent advantages/disadvantages have been around with us for a while.  Advances in technology might thrust one method ahead of the other.  For example, cheap silicon = ascension of delta sigma based dacs.  Different DACs on the higher end of the scale typically try to solve what one designer feels are the core issues with an approach while another designer feels other issues are core to the problem.

 

I do believe there are absolutes in terms of what is "better" at music reproduction on at least a fairly crude level.  My wife, who couldn't give 2 cents about music before and after I met her, mentioned that she thought the music she was hearing at our friend's house (out of a fairly high end system) sounded terrible.  This of course was music to my ears.  At the end of the day however, your ears and your brain will hopefully clue you in as to which sounds better to you because it becomes more subjective and subject to factors (e.g. expectation basis, bright sound bright color, etc.) outside of purely the sound.  Plus your brain does need time to train up (eg. my wife).

 

If you can ignore the marketing angle, here is a pretty simple explanation:

 

http://www.msbtech.com/support/How_DACs_Work.php?Page=supportHome

post #1914 of 14306
Quote:
Originally Posted by Hifi Nutter View Post


Hi Rob,
With you talking about dsd versus pcm what setting should I have my onkyo hf player on,pcm or dop for best sound quality to the Hugo from my iPhone

I am not familiar with the Onkyo, but keep the file to whatever it was originally, don't let the player mess with the bits!

post #1915 of 14306
Quote:
Originally Posted by ted_b View Post
 

As I said in my Qute HD review on CA, I was a DSD-aholic until I heard what the Qute series (now own an EX) does for any PCM, including redbook.  It's DSD is very good too (I think EX's DSD is better than HD but maybe just more break-in) but no longer really care that much about formats, as anything you throw at it is quite musical.

 

I haven't got into DSD yet mainly because a few knowledgeable people have told me the benefits over red-book are negligible if at all, my only foray into hi-res Flac left me somewhat disappointed especially when it was an album I hungered for, Gov't Mule 'live' featuring Robby Krieger (link below)... I was expecting more clarity from the recording but it sounds exactly the same as the CD variants I have of other 'live' albums by Gov't Mule.

 

judging by Rob's answer to another post above, I may as well stick with red-book as it will save me a fortune seeing as DSD albums seem to be priced $40 upwards... I think I need to be convinced, I'd rather invest in equipment that improves things and not some questionable music format, am I wrong?

 

album link: http://www.livedownloads.com/live-music/0,9987/Govt-Mule-mp3-flac-download-10-30-2013-The-Fonda-Theatre-Los-Angeles-CA.html

post #1916 of 14306
Rob excuse my ignorance or lack of knowledge on the subject but in layman's terms do you design your filters around the Spartan chip?Is someone else the brains behind the Spartan as in your interview you said you were building a 20 grand dac around the Spartan 3 then the Spartan 6 came out so you scraped the idea and used the technology in the Hugo,couldn't you design a better chip than the Spartan if this is the case so everything is in house for total quality and is to exact specification for audio
Regards paul
post #1917 of 14306

.


Edited by SleepyOne - 6/13/14 at 5:15am
post #1918 of 14306
Quote:
Originally Posted by Hifi Nutter View Post


Hi Rob,
With you talking about dsd versus pcm what setting should I have my onkyo hf player on,pcm or dop for best sound quality to the Hugo from my iPhone


I'm not Rob (or anything close to it :) ) but my take is that the Hugo will play both formats, so why ask the player (iPhone Onkyo player) to do conversion to PCM when you don't have to.  Leave DoP enabled and that way what is DSD stays DSD (actual recording provenance notwithstanding of course) into the Hugo.  The bigger issue is to be on the lookout for the best version of your recordings.  For example, if you like BIS's music, don't buy their SACDs and rip them to DSF (or DFF) but instead buy them at their native resolution on the eclassical site.  This native resolution may, in fact, be as low as 24/44.1k (for their early recordings that appeared on SACD) but it's the closest to the master, if not the master.  On Chord DACs (cuz they do PCM so well) it's a big enough improvement to care to go out and find this stuff.

 

My "tip" is mostly for stereo playback.  Since BIS (same example) doesn't sell their native PCM surround tracks you'll need the upsampled DSD 5.1 on the SACD for that..currently.

 

Net/net, if it was recorded/mastered in PCM, buy it and play it in PCM.  If it was recorded/mastered in DSD (or analog-to-DSD) then play it in DSD.  Sometimes one format is all we got for hirez, so even if the original material was PCM, if the higher rez PCM is not available to buy you may find that the kidd glove treatment to get it remastered on SACD may be enough to pick that format (over, say, the 80's redbook version).   It's a lot of work, sometimes, but in the end we get as close to the master tape as possible.  This work makes those faux upsamples that appear constantly on the hirez market even more frustrating to see. 

post #1919 of 14306
Quote:
Originally Posted by Rob Watts View Post

I am not familiar with the Onkyo, but keep the file to whatever it was originally, don't let the player mess with the bits!
Rob the onkyo player lets me play high def music from my iPhone to the Hugo,all I've done is burn my cds to the player so still none the wiser whether I use pcm or dop settings
post #1920 of 14306
Quote:
Originally Posted by Crashem View Post

Tell me about it. Too many realms of knowledge are needed today to understand what is going on with the advent of digital.  Luckily for me, I have a fairly technical background, but even with some knowledge, often the underlying arguments get to too deep into the specifics to really understand what is going on.  But some basic understanding however helps you separate the chaff from the wheat.  The funny thing is that the basic methods and the inherent advantages/disadvantages have been around with us for a while.  Advances in technology might thrust one method ahead of the other.  For example, cheap silicon = ascension of delta sigma based dacs.  Different DACs on the higher end of the scale typically try to solve what one designer feels are the core issues with an approach while another designer feels other issues are core to the problem.

I do believe there are absolutes in terms of what is "better" at music reproduction on at least a fairly crude level.  My wife, who couldn't give 2 cents about music before and after I met her, mentioned that she thought the music she was hearing at our friend's house (out of a fairly high end system) sounded terrible.  This of course was music to my ears.  At the end of the day however, your ears and your brain will hopefully clue you in as to which sounds better to you because it becomes more subjective and subject to factors (e.g. expectation basis, bright sound bright color, etc.) outside of purely the sound.  Plus your brain does need time to train up (eg. my wife).

If you can ignore the marketing angle, here is a pretty simple explanation:

http://www.msbtech.com/support/How_DACs_Work.php?Page=supportHome
Crashem nice one mate appreciate it for being helpful,my Mrs weren't into hifi but she loves the Hugo,I always use her ears to tell me which sounds best,she spot on,wish I had her ears,think I'm going deaf lol,if I do I'll save myself a bloody fortune
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