Jriver MC DSD-to-PCM filter setting

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by Original Ken, Oct 20, 2015.

  1. Original Ken

    Original Ken Friend

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    For those who are using a DAC that does not have a DSD setting (such as Schiit Multibit DACs), one convenient and popular way to play DSD files (or SACD ISO files) is to convert them during playback in Jriver MediaCenter to PCM. Jriver MC then treats them as 352.8 PCM files.

    In Tools->Options->Audio->Advanced->Configure Input Plugin->DSD input plugin, there is a setting:

    Low-pass filter used for DSD-to-PCM conversion

    with possible settings:

    Safe (24khz @ 48db/octave)
    Medium (30khz @ 24db/octave)
    Permissive ( 50khz @ 24db/octave)
    Off (external low-pass strongly recommended)

    Don't all PCM DACs have low-pass filters by necessity?

    Is there any compelling reason to not set this to "Off" ?
     
  2. purr1n

    purr1n Finding his inner redneck

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    DSD format consists of a bunch of noise from around 25kHZ upward peaking at around 50 to 60kHz. This is the result of noise shaping to move the crap from 1 bit quantization to the ultrasonic areas where humans can't hear it.

    DSD is hires in the sense that effective bit depth is high in the audible spectrum, but it really doesn't contain any high frequency material past what we can hear.

    SACD players or DSD DACS will apply a similar low pass filter. You don't want to blow your tweeters or some amps may not like the high frequency gunk. In Jriver, I preferred running the most aggressive filter as it sounded the best to me.
     
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  3. The Alchemist

    The Alchemist MOT: Schiit - Here to help!

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    So DSD playback is no good?
     
  4. purr1n

    purr1n Finding his inner redneck

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    DSD is good for the masters. Some boutique labels that record in DSD have produced excellent recordings.

    Some DACS seem to do a better job playing back DSD better than PCM.

    I like to think of DSD as 24/48 PCM equivalent. Doing tests on Vega DAC, I couldn't make out anything better than 18/48 starting with a DSD128 source, converting to PCM and decimating downward.
     
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  5. The Alchemist

    The Alchemist MOT: Schiit - Here to help!

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    ah I see. I remember a quote from Jason at Schiit saying that DSD playback could just be a fad (not an exact quote but something to that effect).

    Thank you Marv for explaining that to me as I use JRiver as well and it has DSD playback functions, but I do not have a DSD capable DAC, just the Bifrost Uber, and the Bifrost sounds good to me! Can't wait to be able to possibly get the multi-bit upgrade for it!
     
  6. Original Ken

    Original Ken Friend

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    Here is a really helpful site that has downloadable test files. All files are converted from the DXD file (which is 352.8khz PCM). If you compare the DSD files to the PCM ones of roughly equal file size, you will that DSD adds a little bit of pleasant sounding distortion that is not in the original DXD file. It is subtle enough that it gives everything a little more impact and oomph, without sounding like distortion. This is why people "like DSD". It's like turning up the sharpness or the color saturation on your TV - looks "better", but is not accurate.

    ( The guys at Schiit have additional objections to DSD in terms of the practical world of music sales and delivery, the above is just about sound quality. )

    Here is the site:

    http://www.2l.no/hires/
     
    Last edited: Oct 20, 2015
  7. purr1n

    purr1n Finding his inner redneck

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    I can send out Loki on the loaner program. DAC quality is more important than format. I like some DSD masters, so I convert them to PCM.

    Unless you are into the boutique label DSD releases, it's a waste.
     
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  8. bixby

    bixby Friend

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    Nice analogy. I always disliked the ripped dsd stuff from all those old sacds. Something not quite right up top. Maybe it is some of that massive noise in the non-audible area modulating or aliasing down into the audible range, or a crappy filter design.

    That being said, there are some newer dsd recordings that sound pretty decent. And yes, I also think it is dac dependent as to whether you are a fan of dsd or not. Me...not.

    Oh, were you going to include a link to that site? I think you may have left it out of your post.
     
    Last edited: Oct 20, 2015
  9. Azteca

    Azteca Friend

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  10. Original Ken

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  11. bixby

    bixby Friend

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    @Azteca - Nice measurements, but I am confused. How does the test methodology you posted relate to what happens when a DSD file is played natively by a dac and not converted to pcm first? Could some of that junk get into the audible band?
     
  12. meloman

    meloman Acquaintance

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    Yep, this is why using a low-pass filter when doing DSD-to-PCM is very important.

    Here is a spectral frequency display of SACD DSD-to-PCM with DSD high frequency noise intact (also that ~22KHz brickwall seems like a suspect for redbook upconvert):
    [​IMG]

    And here is DSD-to-PCM with a 30KHz low-pass filter:
    [​IMG]
    source
     
  13. bixby

    bixby Friend

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    Thanks for the pic, but help me decipher it. I trust the deep pinkish dots peppering the black upper portion of the image is high frequency noise randomly splattered above the 22k limited signal.

    In the second image it is all perfectly black above 22k even though you noted a 30k low pass filter is being used. Even with a really steep cutoff wouldn't there be some noise in that black above 22k ?
     
  14. meloman

    meloman Acquaintance

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    Yes, even though its black, there is still some left even after a filter. Here is another post-filter representation (frequency analysis):

    [​IMG]
     

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