Originally Posted by Souchirou
Audio professionals generally use a 48 kHz sample rate because it is high enough to provide 22 kHz requency response on 29.97 frames per second (NTSC) as well as 24, 25 and 30 frames/s video.
..but there's no increase in audio quality as the sample rate is already at more than the doubling needed to satisfy nyquist
. Even if the DAC doesn't support 48Khz, Windows Vista+ have good quality resamplers that will downsample the DVD audio; you won't need a DAC that supports more than 44Khz other than for win XP, though it's nice to know it's there. I would also advise against setting the soundcard to above 48Khz since there are sometimes audible sound issues from doing so. Ultra high-frequency audio (above 20Khz) can manifest as sub-20Khz distortion. I've actually tested this myself. I immediately set my card to 44Khz.
Another advantage you will find mostly with watching movies is the 24-bit audio bit depth. It provides a higher resolution between very loud and very quite. In movies this mostly shines as it allows for explosions and such to be loud and whispers to still be well defined.
Again, the 96dbs of CD is more than enough for this. The only advantage to 24bit is that it permits digital volume attentuation. With 16bit audio on winXP, reducing the volume also reduced the audio data and compromised audio quality. I've not been able to determine the issue on Vista+ (there are hints that only XP had this issue; that 16bit on Vista+ is fine). To be on the safe side one should select 24bit for your soundcard's config (Vista defaults to 16bit). The audio itself can be 16bit; it's the soundcard that needs to be set to 24bit to avoid 'bit-stripping' of the audio.
As for music it really depends on two things:
1) Do you have / are you willing to acquire music in 24-bit?
There is no advantage to getting audio in 24bit or higher sampling rates than 44Khz. SACD was a total failure probably for this reason.
Asynchronous Transfer (AT) is usually a plus.
Normally your computers internal clock is used to send and time data (audio in this case) but the accuracy of this clock is generally much lower then a dedicated clock on a DAC.
This is where AT kicks in as it allows you to bypass your computers internal clock for sending data over USB and use the much more accurate and stable clock in your DAC.
AT is also not necessary. A properly implemented USB DAC has no need of it. Onboard soundcards don't use USB any way, and since onboard sound on any half-decent modern laptop is already near or at hifi......... (To clarify, AT is an issue for USB devices.)
My advise? Upgrade your music library to 320 variable bit-rate or higher if space allows it. That way you get more out of your DAC and Headphones.
Do some DBT (double blind testing) and soon convince yourself that you only need mp3s at 192kbps vbr.
This speaks for itself.
I don't mean to insult the well-meaning poster, but this info is not the whole truth, so to speak.
I would google "audio myth busting" to get past some of the stuff out there purporting to be fact.Edited by lorriman - 1/17/13 at 3:45am