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MDAC First Listen (part 00101100)

Discussion in 'audio' started by timola, Nov 25, 2015.

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  1. Boozyuzi

    Boozyuzi pfm Member

    Thanks John, will the USB 2.0 on the Fdac (Lite probably) deal with the Mac Mini any better ? It's a 2011 Mac Mini..
     
  2. fusion5

    fusion5 on the dark side of hifi...

    AFAIK the faulty Apple USB implementation is only causing problems with USB 1.1 devices. You could try using an USB 2.0 hub with your MDAC. FDAC should be fine.
     
  3. anjora

    anjora pfm Member

    Could fdac lite work as a slave unit? do i really need this usb detox thing?
     
  4. JohnW

    JohnW pfm member

    Yes - that follows my own experiences here with the MDAC and external HQ PSU... And to be honest it offers too little improvement for the cost (lets say GBP350).... Hence the FDAC Project to achieve that "Leap" in performance.
     
  5. JohnW

    JohnW pfm member

    The Master / Slave interface requires the FPGA - the FDACLite is a simple design without FPGA.
     
  6. JohnW

    JohnW pfm member

    Yes, bot the FDAc and FDACLite will work with "correctly" with the Mac USB2.0
     
  7. JohnW

    JohnW pfm member

    The MDAC HAS no DSP, the Digital filters are internal to the ESS Saber.

    I cannot believe ANYONE can hear a level difference of 0.2dB!! 1dB is recognised as the lowest level difference perceivable by humans...

    Its Optimal Transient filters that I believe are the most popular (Not Optimal Spectrum) - these have a "Perfect" time Domain performance.
     
  8. JohnW

    JohnW pfm member

    Basically for any system where you need more then two channels - eg. Surround Sound systems and Active crossover systems (using the internal DSP) where you perform the Crossover in DSP and send the "filtered" Audio to different DAC Channels / amplifiers to drive the Bass / Mid Range / Tweeter directly.
     
  9. JohnW

    JohnW pfm member

    There will be early engineering units of the FDACLite and a very select few released "into the Wild" :) for 'early' evaluation of the FDAC audio quality - these will help us define the "Fusion Bulk foil resistors" etc. for the flagship FDAC test the USB drivers etc.
     
  10. timola

    timola pfm Member

    How interesting.....So I guess you take the digital file separate this in frequency digitally (in a PC or DSP crossover) and then feed each frequency range to 3 separate FDACs......the analogue signal from these then goes to 3 separate power amps (VFETS)....into 3-way speakers.

    I guess this gives you complete control over the crossover frequencies and filters etc. etc.

    And I guess you need a master FDAC to control the others for volume and data clocking.....very ingenious.

    Wow...seems like a good solution. I have a 3-way active system but the crossover is analogue. I'm guessing that digital crossovers can be made 'perfect' whereas analogue crossovers have some inherent compromises.

    Thanks!
     
  11. timola

    timola pfm Member

    Thanks John, I think I understand now, very interesting......For a 3-way active set-up for example one would need a mindsp 2x8 kit to do the processing and provide the 6 digital outputs to be fed into 3xFDACs and then to 3xVFETS (VFETS may be monoblocks and then you would need 6 of them!!).....Oh the penny is dropping! :D

    I wonder which speakers Adamdea has?
     
  12. adamdea

    adamdea You are not a sound quality evaluation device

    I was under the impression that 0.1dB was the strict requirement for blind testing and that that was regarded as being just under the minimum perceptible difference.
    This source quotes 0.2-0.4dB
    http://www.indiana.edu/~emusic/etext/acoustics/chapter1_loudness.shtml
    (mind you 0.2 dB is still 0.2dB more than the difference caused by an asynch usb reclocking device)
     
  13. adamdea

    adamdea You are not a sound quality evaluation device

    Yes, I think some active speaker manufacturers do this all in one box (Genelec for example). The problem if you are doing it bespoke you need to make sure the dacs are exactly synchronised, hence the master/slave thing.

    Apart from the fact that the digital crossovers should be more accurate, there is the attraction that you can apply room correction at the same time.
     
  14. misterdog

    misterdog Not the canine kind

    Sheffield is renowned for being "Wild" ;)
     
  15. timola

    timola pfm Member


    A very interesting acrticle...Cheers!
    The balance on the MDAC goes up in 0.5dB steps .... I need at least 1dB to notice a change.....but I'm glad designers out there can hear 0.2 - 0.4 dB differences...hence why John wants a panel of good testers/listeners for the FDAC....maybe he's getting too old (like me):D
     
  16. adamdea

    adamdea You are not a sound quality evaluation device

    On the other hand this article suggests 0.75dB to 1db with music, which seems to match your experience
    http://www.audioholics.com/room-acoustics/human-hearing-amplitude-sensitivity-part-1
     
  17. fusion5

    fusion5 on the dark side of hifi...

    Except you won't need the minidsp 2x8 since the FDACs will do all the processing.
     
  18. timola

    timola pfm Member

    You'll try anything....it was (sadly no longer) renowned for Steel...perhaps you meant on a Friday night.
     
  19. timola

    timola pfm Member

    How would you get the same digital file simultaneously into 3 separate FDACs?
     
  20. fusion5

    fusion5 on the dark side of hifi...

    You only need to feed the Master FDAC which will distribute data & clock (via separate connections) to the Slave FDAC(s).
     
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