CD vs. NAS

July 27, 2019
 by Paul McGowan

5 comments on “CD vs. NAS”

  1. Stored music can sound better than all but the most expensive cd players. It is not necessarily easy however.

    It should be noted that it is possible (recommended actually) to send music from the NAS to the DAC without going through a computer on the network. Also, some DACs, like the Directstream, can attach directly to the network. This ability simplifies set-up and sounds good, however it can be still improved with more electrical isolation and noise reduction.

    Computer audio is like fly fishing.

  2. I thought the problem of jitter was solved already some 20 years ago bei Ed Meitner’s DAC-designs found in his Idat and BiDat models. The biggest problem of a CD-player is the real-time reconstruction of the original analog signal from the bit sequence using more or less sophisticated error correction schemes. Thus I always had better sound quality from a music server using a big RAM buffer for the digital data received from the internal HDD. And I read that there are CD-transport out there using such a RAM buffer too. Didn’t come one of the first designs with RAM-buffer came from Krell? Shouldn’t computer noise easily be filtered by galvanic isolation? Shouldn’t be no rocket science at all!

  3. I've stumbled on something that sounds surprisingly good, considering the price. I have the Plex app running on my NAS, and a $50 Roku Stick plugged into an HDMI input on my receiver in another part of the house (I do like the physical distance from mechanical operations that Paul mentions). There is a Plex channel on the Roku Stick, so I have a direct connection to the NAS, and stream music through it, and I think it sounds great.
    When working with the Plex library, I have a laptop connected to the Plex server page on the NAS, and I find the Plex playlist management software to be very easy to use to cope with a large library and build/edit playlists easily. When playing back music through Roku, the response times are much faster than what I see using an otherwise excellent Oppo blu ray player with a DLNA connection, and Roku playback means no laptop or USB or SPDIF connection at all to contend with.

  4. All of my CDs are ripped to FLAC using JRiver. Those digital files are then placed on a Western Digital 4TB MyBook USB drive and connected to my Oppo Sonica DAC using a quality USB cable. I find that those former CDs do sound better as digital computer files. I suspect that part of the explanation is that the files from the CD were error corrected within JRiver while being ripped. They do not need to be error corrected while the CD is spinning on the CD transport as happens with a CD player. The ESS Sabre DAC chip in the Oppo may also produce better analog music streams than my CD transport--as least better to my ears.

  5. If music from a CD is copied to data files in a lossless format, the data should be unchanged, give or take the occasional non-correctable error when reading the CD. If a CD transport sounds different from a NAS when the two sources are played through the same DAC then we're hearing something other than errors in the stored data or the analogue performance of the DAC. The difference might be caused by using a noisy clock at the DAC, and it's possible that one of the two approaches works better in this regard. We'd need to know more about how that clock is derived, and what buffering is provided at the input to the DAC. Paul has talked about this several times, but I'm still not certain how the clock is generated in each case. In the case of a CD transport, I'm assuming that the CD transport is the clock source. There's no reason why the DAC should not extract a clock from the S/PDIF signal, use this to read data into a buffer, lock a clean clock to the incoming jittery signal, and use the clean signal to drive the conversion. Am I missing something?

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