Originally Posted by moooog
I need some help understanding how the PIoneer's internal USB-DAC is superior to simply using the DACs in any receiver like an Arcam or Anthem. I have a HTPC with an ATI 5670 card, and listen to lossless files over HDMI passtrhu to a Denon 4308 receiver - would the Pioneers Internal DAC represent an upgrade for me, or would it mainly be an upgrade for someone listening from a Laptop with a soundcard? I have read extensively on the subject, and still don't quite understand whether someone with a HTPC really needs an external DAC.
I am yet to be impressed with the USB-DAC, I don't think that Pioneer have it working optimally yet. It may still sound better than your setup with sound card though due to the issues with playing digital audio through a regular PC audio card.
I don't know if it helps or not, but I would like to mention what I found out when researching computer audio and how I ended up with the adapter which I am using. Sorry if it is a bit long and reads like a volume of War and Peace
I have been playing around with computer audio with my old Denon AVR for about a year. I also did a lot of research and came to the conclusion that to give me the best possible audio I needed to achieve the following:
1. Bit perfect reproduction
2. Low latency
3. lowest possible clock jitter
4. Bypass the Windows mixer
I read that by default PC audio cards and on board audio devices have problems with all of the above. (Macs less so). I came to the conclusion that I needed an adapter, and found there were two possible approaches:
a) USB to S/PDIF adapter
b) USB DAC ( I.e. with analogue output)
Since the vast majority of the time my equipment was being used for watching movies, it made sense to go with option a). The only thing I was concerned about at that time was whether the DAC in my Denon was up to snuff. All I knew about it was that it could handle up to 24bit at 96Khz. Option a) also gave me the option to upgrade to an external DAC if the one in my Denon proved inadequate.
So I set out to find an affordable USB to S/PDIF adapter. I had read about M2Tech's HiFace adapter and almost went for that, but stumbled across a review of the Mapleshade adapter, on which it is based. The Mapleshade adapter utilizes asynchronous USB, which apparently is preferred way of transferring digital audio from a computer. Even with asynchronous USB the jitter can still be pretty bad and so adapters like the Mapleshade employ re-clocking circuitry to further reduce the jitter. Mapleshade claimed to have put a lot of work into improving the clock jitter from the original HIFace. The review was very positive and talked about how 'musical' it sounded.
BTW, I have no idea what is an acceptable number for the clock jitter critical jitter is, all I knew from my research was that clock jitter can be a major contributor to computer audio sounding 'digital' and tiring to listen to over extended periods.
As to the latency concerns, why does it matter if audio takes 10ms or 500ms to arrive? To be honest I am not sure, maybe if it is not fixed and changes it becomes a problem? Anyway, I set about finding adapter which would work with ASIO as I read that was the way to get very low latency and bit perfect reproduction. I slipped up a little when I bought the Mapleshade adapter as I thought it was supported under ASIO but was wrong. However, I discovered ASIO4ALL as a way of getting ASIO like latency but using WDM. ASIO4ALL is a wrapper for WDM which achieves very low latency and bypasses the Windows Mixer. ASIO4ALL has been working great for me, and has the added benefit that I don't get the Windows system sounds going through it.
From what I read the Pioneer USB-DAC uses asynchronous USB and performs re-clocking, and it is capable of going to 32bit at 192Khz. If done right, it should sound really good but I have not found this to be the case yet. I suspect that Pioneers driver needs note work, possibly to make it work with ASIO.
I remember finding a really good article on the problems with computer audio, I will try to find it and post a link to it in this thread.