I have been researching this subject for the last two years. Unsurprising to many, my overall conclusion is that there are two main issues: a) the computer has to be extra-ordinarily optimized, like everything else in the audio chain; and b) USB is an inferior interface to AES/EBU. Convenience aside, to invest, thus, in such a source system I would then have to be itching to own true hi-rez material, like RR HRx, which I don't since 16-bit + HDCD comes close enough to true hi-rez, therefore not worth my trouble. Subsequently, it then became a simple question for me: could I come up with a computer configuration (hardware and software) that would be more optimized than a stellar transport like the Spectral SDR-3000 and the Berkeley Alpha DAC, which I use, using the AES/EBU interface?
On the hardware side, as a consumer, it's virtually impossible to figure out what exactly works best (see more below). On the OS side, Windows-based servers appear not to be the best candidates for this type of application, but UNIX-based, like mach2music.com (or any Mac-based) perhaps fit the bill better. Sadly, mach2music has been out of business for some time now. Some folks have gone to extraordinary lengths to optimize the playback, like Jplay that's been discussed here a number of times. TAS, in its January 2012 issue, features a very nice article that attempts to rate ripping, playback, burning and other software, and at the top we find a couple of offerings, like JRiver for ripping and the user interface plus JPlay as the preferred playback as a plugin to JRiver, in Hibernate mode to shut down as much of the Windows PC functions as possible, and for other reasons like loading the entire track in memory before playback. This combination is apparently favored over Foobar2000 and cPlay (by many on the net as well as the reviewer below).
Say what we may about many reviews, but the 6moons piece on Jplay is dead on with what I know and have observed, and a real must-read in my mind: http://6moons.com/audioreviews/jplay/1.html. Here are some excerpts worthy of special attention:
Well, my standard Redbook has been sounding great for a very long time...
With respect to hardware:
And to top it all off:
Technology aside, I have never really been wowed with the sound of Redbook when my dealer drives the Alpha DAC from his optimized server (and I believe they have also evaluated a number with minimal success), except when playing HRx - but then it's the true hi-rez material that trumps Redbook, not the server itself. In the end, no matter how good a USB-to-SPDIF bridge one builds, I can't see how the overall approach can better a direct SPDIF or AES/EBU feed from an excellent, optimized transport. What I need is a stellar, dedicated CD/DVD-A/SACD transport and a DAC to go with it - or better still, DACs where you first upload the entire content and then interact with them exclusively (memory is so cheap these days!). So as far as DIY computer-based audio goes in the here and now, I am done with this subject, probably for a very long time - and I don't need the convenience either. On with trying to figure out which commercial products fit my ideal architectural approach.
On the hardware side, as a consumer, it's virtually impossible to figure out what exactly works best (see more below). On the OS side, Windows-based servers appear not to be the best candidates for this type of application, but UNIX-based, like mach2music.com (or any Mac-based) perhaps fit the bill better. Sadly, mach2music has been out of business for some time now. Some folks have gone to extraordinary lengths to optimize the playback, like Jplay that's been discussed here a number of times. TAS, in its January 2012 issue, features a very nice article that attempts to rate ripping, playback, burning and other software, and at the top we find a couple of offerings, like JRiver for ripping and the user interface plus JPlay as the preferred playback as a plugin to JRiver, in Hibernate mode to shut down as much of the Windows PC functions as possible, and for other reasons like loading the entire track in memory before playback. This combination is apparently favored over Foobar2000 and cPlay (by many on the net as well as the reviewer below).
Say what we may about many reviews, but the 6moons piece on Jplay is dead on with what I know and have observed, and a real must-read in my mind: http://6moons.com/audioreviews/jplay/1.html. Here are some excerpts worthy of special attention:
there are several settings you can experiment with such as Buffer. Essentially use the lowest possible setting possible before you get ticks and pops. This will depend on your computer’s specs, your audio interface driver and the bit depth/sampling rate of the music files.
...
I found this feature to have a profound impact on sound quality. Interestingly, Josef pointed out in an email exchange that it is impossible to send one sample at a time to a DAC via USB even with 16-bit/44.1kHz (1/44100 = 23 microseconds) material. The lowest any USB DAC or USB-SPDIF interface can support is 1000 microseconds due to limits imposed by USB. Even the new USB 3 standard is limited to 250 microseconds. That still leaves 10 samples as the absolute minimum package one can send down a USB pipe at a time. Regardless of which USB standard your gear uses, its driver still has to buffer samples before shooting it down the wire. So one has to ask how feeding a USB driver one sample at a time can possibly affect sound quality. According to Josef, "it's a real mystery but the fact that most people report sonic benefits with smaller buffers just shows how little we know about computer-based music playback and why this exciting area still has some room to grow."
Hibernate Mode is arguably the most powerful feature which shuts down every non-essential process including I/O devices and leaves just enough computer resources to play music but nothing else. Once you have loaded an album, track or playlist into Hibernate Mode, you lose control of your PC until playback is finished. Your screen will go black, keyboard and mouse will stop functioning.
Going FullScale Hibernate mode again upped the ante. Here was the absolute pinnacle in sound quality. Even standard Redbook sounded great
Well, my standard Redbook has been sounding great for a very long time...
With respect to hardware:
One wonders what else could possibly improve playback further. Indeed I asked Josef and Marcin that very question. There’s already a lengthy thread on their forum discussing this. According to Marcin, "the PC should be treated with the same attention to detail as any regular mechanical transport. Obviously there are very few 'audiophile' PC components available and this field is also very new so we have to experiment. But I can tell you that almost everything matters: quality of power supply, power cord quality, motherboard selection, RAM selection, almost every component - even USB or SATA chip sets have an effect on SQ as do SATA cables. Right now I use JPlay with my operating system on an SSD in an external SATA-USB enclosure powered by a linear PSU connected to the PC via USB over fiber-optics extender and high quality USB cable. My DAC also is connected via USB over a fiber-optics extender."
And to top it all off:
Addendum: Just prior to publication I installed the latest beta of Windows 8 as per Marcin’s and Josef’s prompting. I’m not sure what Microsoft has altered in their coding over Windows 7 that could cause this but there’s clearly greater textural fidelity and a more natural relaxed sense of flow.
Technology aside, I have never really been wowed with the sound of Redbook when my dealer drives the Alpha DAC from his optimized server (and I believe they have also evaluated a number with minimal success), except when playing HRx - but then it's the true hi-rez material that trumps Redbook, not the server itself. In the end, no matter how good a USB-to-SPDIF bridge one builds, I can't see how the overall approach can better a direct SPDIF or AES/EBU feed from an excellent, optimized transport. What I need is a stellar, dedicated CD/DVD-A/SACD transport and a DAC to go with it - or better still, DACs where you first upload the entire content and then interact with them exclusively (memory is so cheap these days!). So as far as DIY computer-based audio goes in the here and now, I am done with this subject, probably for a very long time - and I don't need the convenience either. On with trying to figure out which commercial products fit my ideal architectural approach.