10 Apr
2007
10 Apr
'07
9:28 a.m.
Dmitry Baikov wrote:
On 4/10/07, Robin Gareus <robin(a)gareus.org>
wrote:
good point. now I start to remember the protocol mess and overhead of
1394 audio. - and hope I'll forget about it again soon.. ;)
PCMCIA is ok, but not great for low latency.
(adds one extra interface
between PCI bus & sound-card). - the cheap solution is to get a PCMCIA
card for your hard-disk - instead of using the built-in firewire for the
disk. - maybe you want to do that anyway. use the built-in firewire to
an external audio-device and the PCMCIA for storage.
Quite the opposite.
PCMCIA is great for latency. That "extra" PCI bridge does NOT affect
audio latency.
Firewire latencies are bigger than PCI/PCMCIA and will always be. Ask
Pieter Palmers for details. So if you are for low latency, PCI/PCMCIA is
unbeatable.
If you want numbers, I can provide them for Echo Indigo IO and RME
MultifaceII.
why not? a LAU-Poll can launch a "known to work professional gnu/linux
sound setups and their specs&tweaks" wiki page.. I wanted to pull out
some information of prev. emails and x-link archived emails to the
linuxaudio.org wiki... maybe next weekend..
Ask somebody to jdelay their Firewire card.
it's not easy to interpret jdelay's output, is it?
i get a lot of those running jdelay at 48kSPS -f64 -n2 for the UA-25.
24404.495 frames ?? Inv
24404.345 frames ??
24404.241 frames ?? Inv
24404.181 frames ??
sometimes it "flips" and displays
44664.987 frames ??
43225.215 frames ?? Inv
8585.183 frames ??
or other weird jumps that all add up to 48k. Then goes back to repeat
the 24400 pattern. - i can tell that 24400/48000 is not the latency ;p
and guess it means a total round trip latency of around 800 frames or 16 ms.
btw. if i move a headphone relative to the mic, jdelay allows to track
its distance with about a 2cm accuracy. how cool!
the built-in HDA reports:
59328.024 frames ??
59328.024 frames ?? Inv
59328.024 frames ??
59328.024 frames ?? Inv
59328.024 frames ??
59328.024 frames ?? Inv
59328.024 frames ??
59328.024 frames ?? Inv
9608.520 frames ??
9608.643 frames ?? Inv
9608.536 frames ?? Inv
9608.549 frames ??
9608.485 frames ?? Inv
9608.449 frames ??
59328.154 frames ?? Inv
59328.147 frames ??
8584.172 frames ?? Inv
59328.193 frames ??
not sure how to make sense of that, yet. something's oscillating over
here, where's the javascript-power-spectrum-paste-bin? lol. ;)
#robin