On Sun, Mar 8, 2015 at 10:59 PM, Bill Unruh <unruh@xxxxxxxxxxxxxx> wrote: >> >> Is it though? I haven't yet found specific details on what >> intermediate format is used ... All I know so far is "32 bit". Could >> be floating-point, and I don't know if there's any sample rate >> conversion going on. Although that would be odd. > > It is not rate conversion, just integer conversion, from 16 bit to 32 bit. > Actually, it's 16-bit integer to 32-bit floating point and back. I don't know how I missed that at first, it's right on the front page. D'oh! :D > Now, if the original is maximal (Ie goes from +2^15 to - 2^15) then > conversion, and then any other filtering, could drive the system into > clipping > on back conversion. It can also introduce a bit more digitization noise > (90dB > down from the max), but neither is likely to anywhere near as severe as the > noise introduced by rate conversion. You are probably using the fastest rate > conversion which is horribly distorting. Actually, as you can see from my asoundrc I'm using the Secret Rabbit Code SRC at the "best" setting, and AFAICT it's the best one on offer from ALSA. Also, there's only going to be rate conversion on the one output that requires it (the NAD DAC). The other output, which I'd like delayed, is at this point completely free from any format conversions (FLAC -> AirPlay -> SPDIF -> AudioAlchemy 2.0). That's why I'd like to avoid to introduce any :) Thank you for your input, Bill, and for the link, it'll be my breakfast read :) Daniel > See www.theory.physics.ubc.ca/soundcard/resample.html > for tests of the various conversion procedures contained in sox (and I think > the alsa ones are closer to the fastest/worst, rather than the slowest/best) > > >> > ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
