[linux-audio-user] jack latency & MIDI latency (PCI Audigy player)--> digital output

[Robert Jonsson]

Hi,

onsdagen den 1 oktober 2003 16.06 skrev Antonio:
> Thanks to all for the anwers.
>
> Anyway (there have been some incomprention) my card is a pci audigy
> player, not an usb one.
>
> I use for example ams in realtime driven via midi. If I don't use jack
> and output directly to alsa, why doesn't the latency decrease?
> I think:
>    midi in latency + synth lat + alsa out lat
> instead of
>    midi in latency + synth lat + jack lat + alsa out lat
>
> What's wrong?

As Fernando pointed out jack doesn't add any latency, it's the same audio 
buffers that are filled every iteration.

Jack does add somewhat to the CPU utilization, but the price for that is very 
low when compared to the connectivity possibilities you aquire.

To lower the latency you need to adress the buffering on the soundcard. 
Some softsynths may have their own internal buffers that may add to the 
latency. Normally this isn't a problem though.

As for the scenario you laid out eariler.
Using softsynths at 2x512, I do exactly that and I think it's quite usable. My 
system can usually go lower than that, latency wise, but I don't feel a need 
to put the extra load on the system.

>
> I've another issue. When I use the digital output of my card I cannot
> adjust the volume, but only mute/unmute the output from the alsamixer.
>
> Is it a driver limit or maybe have I to put something in asound.conf (I
> don't have that file, only asound.state)?

I have both an Audigy and an SB-Live, to my knowledge I can't make any of them 
use buffers smaller than 512 frames.
But as I said earlier, I'm convinced it's a driver issue and may be fixable.

/Robert

ps. Here's a link to the windows sb-live audigy drivers I mentioned:
http://kxproject.lugosoft.com/index.php?skip=1 
ds.