Home of the Squeezebox™ & Transporter® network music players.
Page 1 of 2 12 LastLast
Results 1 to 10 of 12
  1. #1
    Junior Member
    Join Date
    Jul 2005
    Location
    Blaine, WA/Richmond, BC
    Posts
    11

    Sound quality varible digital out vs. fixed digital output

    Hi all.
    This is my first post, but I have been reading the various posts with enthusiasm and I am a self-professed audiophile.

    I was wondering if forum members suggest using the fixed digital output or the variable digital output to get maximum sound quality with an external DAC?

    Cheers,
    Dennis

  2. #2
    Senior Member
    Join Date
    Apr 2005
    Location
    Raleigh, NC
    Posts
    410

    Sound quality varible digital outvs. fixed digital output

    WK446 wrote:

    > I was wondering if forum members suggest using the fixed digital output
    > or the variable digital output to get maximum sound quality with an
    > external DAC?


    Welcome.

    Fixed.

    Topic's been done to death, but the upshot is that for perfect
    bit-fidelity, use Fixed.

    But if SB remote volume control is a good feature for you then go ahead
    and use it. Volume may ramp into inaudibility well before resolution
    losses rear up.

    --rt

  3. #3
    Junior Member
    Join Date
    Jul 2005
    Location
    Blaine, WA/Richmond, BC
    Posts
    11
    Thanks RT...

    Cheers,
    Dennis

  4. #4
    Senior Member pfarrell's Avatar
    Join Date
    Apr 2005
    Location
    Wayne, PA
    Posts
    4,251

    Sound quality varible digital outvs. fixed digital output

    On Fri, 2005-07-29 at 15:04 -0400, ron thigpen wrote:
    > > I was wondering if forum members suggest using the fixed digital output
    > > or the variable digital output to get maximum sound quality with an
    > > external DAC?

    > Fixed.
    > Topic's been done to death, but the upshot is that for perfect
    > bit-fidelity, use Fixed.


    Ron's right. Use fixed.
    If you alter the volume, for perfection you would have
    to redither the data. And that would start discussions
    about which dithering algorithm to use, how we
    could get the SBx2 to apply the right dither on the fly
    and all sort of stuff that isn't worth getting into.

    Use the volume knob on your preamp.

    BTW, on my Classe integrated amp, I had to
    change internal jumpers on my Benchmark DAC-1
    as it was overdriving the Classe' input side.


    --
    Pat
    http://www.pfarrell.com/music/slimse...msoftware.html



  5. #5
    Junior Member
    Join Date
    Jul 2005
    Location
    Blaine, WA/Richmond, BC
    Posts
    11
    Pat,

    Were you referring to the balanced output jumpers on your DAC1? I was informed that 0dB was the best setting for sound quality.


    Quote Originally Posted by pfarrell
    BTW, on my Classe integrated amp, I had to
    change internal jumpers on my Benchmark DAC-1
    as it was overdriving the Classe' input side.


    --
    Pat
    http://www.pfarrell.com/music/slimse...msoftware.html

  6. #6
    Senior Member pfarrell's Avatar
    Join Date
    Apr 2005
    Location
    Wayne, PA
    Posts
    4,251

    Re: Sound quality varible digitalout vs. fixed digital output

    On Fri, 2005-07-29 at 16:16 -0700, WK446 wrote:
    > pfarrell Wrote:
    > > BTW, on my Classe integrated amp, I had to
    > > change internal jumpers on my Benchmark DAC-1
    > > as it was overdriving the Classe' input side.


    > Were you referring to the balanced output jumpers on your DAC1? I was
    > informed that 0dB was the best setting for sound quality.


    I'm using balanced outputs, I have lots of XLR cables for my recording
    studio. I don't remember if the jumpers control both balanced and RCA,
    or just one or the other. I wacked 20dB off. Just checked the benchmark
    site, they have the manual online, they call it
    "XLR Output Attenuation Jumpers (P5, P6, P7 and P8)"

    I did not use the ten turn attenuation pots.

    Overdriving the preamp caused easily audible distortion.
    Reducing it clearly improved my sound quality.

    --
    Pat
    http://www.pfarrell.com/music/slimse...msoftware.html



  7. #7
    Senior Member Yannzola's Avatar
    Join Date
    Jun 2005
    Location
    Seattle, WA
    Posts
    490

    Related question...

    Quote Originally Posted by pfarrell
    Use the volume knob on your preamp.
    I'm considering putting together a new hifi rig, with the SB2 as the only source. I was hoping to bypass analog volume control altogether... relying instead on the SB2 digital volume control of the analog out via RCA. Of course, the trade off here involves dropped bits vs. the potential signal loss introduced by adding volume controls in the analog signal path. 99% of what I'll be listening to are 16bit Flacs. Will the 24bit digital volume control give me any headroom before modifying the signal? Or is the signal modified (re-aliased?) as soon as the digital volume is no longer fixed at 40?

    Basically, I'm wondering which is better (less sonically degrading) given the choice: adjusting the volume digitally or adding some sort of analog volume control into the stream?

    y.
    Last edited by Yannzola; 2005-07-29 at 17:27.

  8. #8
    Senior Member
    Join Date
    Jul 2005
    Location
    Massachusetts
    Posts
    290

    I'm thinking the same as Yannzola

    ...and for me, the remote control beats walking across the room to adjust volume even if there's a slight quality penalty.

    . . . o O ( As long as I don't lose the remote )

  9. #9
    Senior Member pfarrell's Avatar
    Join Date
    Apr 2005
    Location
    Wayne, PA
    Posts
    4,251

    Re: Sound quality varible digitalout vs. fixed digital output

    On Fri, 2005-07-29 at 16:39 -0700, Yannzola wrote:
    > Of course, the trade off here involves dropped bits vs. the
    > potential signal loss introduced by the adding volume controls in the
    > signal path.


    You lose a bit every 6dB of attenuation you ask for.
    You only get the theoretical 96dB signal to noise
    ratio at wide open. When you cut it by 30dB, you
    are talking about 11 bit signals.

    > 24bit digital volume control give me any headroom before modifying the
    > signal?


    I'm not sure what you mean here. 24 bit has no more headroom.
    The normal way to look at digital signals is that zero dbfs
    is the max. (dB full scale). Signals max out at 0 dBfs, and
    get smaller.

    > Or is the signal modified (re-aliased?) as soon as the digital
    > volume is no longer fixed at 40?


    I don't know what you mean by re-aliased. Standard practice would
    be to re-dither. Someone from SlimDev would have to comment
    on what their algorithm does.

    > Basically, I'm wondering which is better (less sonically degrading)
    > given the choice: adjusting the volume digitally or adding some sort of
    > analog volume control into the stream?


    I think the answer depends on too many things, like the algorithm used
    mentioned above. I bought my Classe years before I got my first
    SqueezeBox. If I was starting over, I would consider skipping the
    preamp completely and running the SqueezeBox directly into a pair
    of monoblocks. If you later decided that you needed a preamp,
    you can always add one.

    --
    Pat
    http://www.pfarrell.com/music/slimse...msoftware.html



  10. #10
    Senior Member Yannzola's Avatar
    Join Date
    Jun 2005
    Location
    Seattle, WA
    Posts
    490
    Quote Originally Posted by pfarrell
    I'm not sure what you mean here. 24 bit has no more headroom.
    The normal way to look at digital signals is that zero dbfs
    is the max. (dB full scale). Signals max out at 0 dBfs, and
    get smaller.
    It's only natural you don't know what I mean when I don't really know what I'm talking about. ;-)
    Quote Originally Posted by pfarrell
    I don't know what you mean by re-aliased. Standard practice would
    be to re-dither. Someone from SlimDev would have to comment
    on what their algorithm does.
    Re-aliasing.... you know...uh... OK. See above. Basically, I was asking if <bad things> occured when the digital volume wasn't all the way to 40. uhhh... I think I should stick to using non-sense words when describing things I do not fully grok. It's only fair to make the extent of my ignorance obviously explicit.
    Quote Originally Posted by pfarrell
    I bought my Classe years before I got my first
    SqueezeBox. If I was starting over, I would consider skipping the
    preamp completely and running the SqueezeBox directly into a pair
    of monoblocks. If you later decided that you needed a preamp,
    you can always add one.
    Aha! Yes! This is what I was really after. If you had to do it from scratch.... would you (in a single source situation) bypass the pre-amp and go directly to amplification, using the digital volume control of the SB2 for attenuation.

    You =would= skip the pre-amp. Good answer... that saves me money!
    Thanks pfarrell!

    y.
    Last edited by Yannzola; 2005-07-29 at 18:59.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •