WAV vs. FLAC vs. AIFF

DTC - I believe the problem is latency and interference, not CPU usage. When the core audio stack interferes with smooth execution of the FLAC CODEC, this is where the problems start.

Has nothing to do with async USB converter and delivering data to that.

Have you tried changing the FLAC file back to .wav with dbpoweramp and compare the two tracks by listening?

Steve N.
Empirical Audio

First, sorry for moving the discussion to the age old jitter, timing discussion.

Steve - I do understand everything that is going on. I belive the flac codec is filling a buffer, in my case the memory buffer for J River. I am assuming that J River decompresses the flac before it goes into memory, but that might not be the case.

If the audio stack delivers in real time, rather than through a buffer, then the question seems to be what the async driver (like the M2Tech one you use) is actually doing. My assunmption was that the async driver is drawing from a buffer, not from real time delivery of data from the Windows audio stack. That may be incorrect. Do you have enough details on the async drivers to know if process swapping can actually effect the async driver significantly? If there really is a problem there, then improving the clocks in async converters should not be important. It is a complicated process. I probably just do not have enough detail on the audio stack/asyn driver to understand why flac decoding (or any other running process) should interfer with the async driver timing.

I am not trying to be argumentative. I just do not understand the internal details of what is actually happening.

I do not hear a difference between wav and flac files. But I believe my DAC also reclocks so that may be the determing factor.

I have not done extensive comparisons, but .wav and flac seem to be a wash in terms of inherent sound quality due to format alone. The difference is what is done with teh format, ie how well the recording is made and how well delivered during playback. Just like CDE, vinyl or any other format, recording quality will range from very bad to very good.

The main considerations are compatibility with your gear and how you will handle metadata/tagging.

flac is better for flexible metadata and tagging over time, if that is something you really want to spend time doing. Personaly I do not. I mostly use .wav and make sure the metadata is correct before ripping. This approach works well ripping with Windows Media Player (good quality rips possible and is included with most WIndows computers) and using Logitech MEdia Server (formerly Squeezeserver) as the music server for Squeeze or other compatible devices . The caveat is thatyou cannot change metadata tags (artis, album, title, etc.) once ripped with .wav. You have to redo the rip with new metadata to make a change, which is pretty easy assuming you actually have access to the original CDs ripped when needed. I recommend keeping your CDs as archived versions of your music and for reference as needed. Do not rip and then get rid of the CDs. You might regret it later.

You need to pick another program to rip .flac, but once you do, then that format works well for editing tags when needed and also sounds good with the Logitech/Squeeze system.

Beware of any conclusions drawn about sound quality differences between formats based on a limited test sample. any results are possible. In teh end, I believe the format to be essentially a wash in regards to how good it can sound.

"Do you have enough details on the async drivers to know if process swapping can actually effect the async driver significantly? If there really is a problem there, then improving the clocks in async converters should not be important."

Improving the master clock in async USB converter is always worthwhile, even if your DAC resamples. Resampling of course puts the jitter of the resampling clock on the data stream, so it can make things worse for sure.

The clock in the USB converter is orthogonal to the problems with FLAC decompression I believe. They are both important effects.

Steve N.
Empirical Audio

Steve N.
Empirical Audio

Mapman - whether you can hear these differences or not is highly dependent on your system. For instance, if you use an active preamp of any kind, you may not hear a difference. Preamps add a layer of noise, distortion and compression that is significant. Until you run without a preamp (and I dont mean with a resistive passive linestage), you will not realize how much grunge your pre actually adds.

I always believed that my highly modified Mark Levinson Pre was really transparent. Then I built a DAC with a good volume. Boy was I wrong. The pre is now gathering dust...

Steve N.
Empirical Audio