Buffered DAC and sampling rate switching issue
Posted by: JYOW on 07 January 2010
I encountered a similarly “interesting” problem with my Weiss DAC which highlights an issue with a buffered DAC (like the Naim DAC and the Weiss DAC) Vs automatically switching of sampling rates.
I have my Weiss DAC connected via Firewire to a Macbook Pro. When in Firewire mode the Weiss DAC does not know how to switch between different sampling rate automatically. Every time I change play tracks of differing sampling rate I have to Quit iTunes and use the Weiss software to switch sampling rate and enter iTunes again to play. Sort of a minor inconvience.
In contrast, my new Cambridge 650BD Universal player (which supports almost every media formats and sampling rates under the sun), is doing the complete opposite. It instruct the DAC to reset sampling rate at the beginning of every track, which creates the “interesting” problem below:
Since the Weiss DAC is buffered, there is a half second delay before a track is played. And interestingly, it cuts off the first half second of every song instead of delay the start-of-play for half a second. My guess is they do that to avoid lip-sync delay. If they delay audio, the video of Blu-Ray/DVD would loss sync with the audio.
One way around this would be if the disc player would only use one sampling rate per disc without resetting after each track. But that would not work for discs with different sampling rates between tracks, which is common in DVD/BluRay video discs, and I have some DVD-Audio discs that has 96KHZ in one track and 192KHZ in the next one.
Since I am also considering the Naim DAC, I wonder how the Naim DAC which is also buffered would handle this issue. Has any one tried the Naim DAC with a DVD player or a Universal player?
I have my Weiss DAC connected via Firewire to a Macbook Pro. When in Firewire mode the Weiss DAC does not know how to switch between different sampling rate automatically. Every time I change play tracks of differing sampling rate I have to Quit iTunes and use the Weiss software to switch sampling rate and enter iTunes again to play. Sort of a minor inconvience.
In contrast, my new Cambridge 650BD Universal player (which supports almost every media formats and sampling rates under the sun), is doing the complete opposite. It instruct the DAC to reset sampling rate at the beginning of every track, which creates the “interesting” problem below:
Since the Weiss DAC is buffered, there is a half second delay before a track is played. And interestingly, it cuts off the first half second of every song instead of delay the start-of-play for half a second. My guess is they do that to avoid lip-sync delay. If they delay audio, the video of Blu-Ray/DVD would loss sync with the audio.
One way around this would be if the disc player would only use one sampling rate per disc without resetting after each track. But that would not work for discs with different sampling rates between tracks, which is common in DVD/BluRay video discs, and I have some DVD-Audio discs that has 96KHZ in one track and 192KHZ in the next one.
Since I am also considering the Naim DAC, I wonder how the Naim DAC which is also buffered would handle this issue. Has any one tried the Naim DAC with a DVD player or a Universal player?
quote:When in Firewire mode the Weiss DAC does not know how to switch between different sampling rate automatically.
Very annoying. There is no technical reason not to detect sample rate from Firewire automatically. I mean I agree there is no standards to send a sample rate over Firewire like it happens to be via USB but there is no issue to customize it through PC/MAC conduit software.
quote:And interestingly, it cuts off the first half second of every song instead of delay the start-of-play for half a second.
Why not to make a switch between sync and non-sync modes and place it on the front
panel and duplicate it in PC/Mac conduit interface
Anyway it's all about music after all -- interesting to know how does Weiss sound through Firewire comparing to Naim DAC through S/PDIF with a transport like CDX2-2 or HDX. If we are not that lazy to turn over the vinyl every 20 min there is no problem to switch a sampling rate when needed.