Full duplex soundcard via ALSA?

Full duplex soundcard via ALSA?

Post by Jesse F. Hugh » Mon, 12 Aug 2002 05:48:46



Hey ho.

I'm giving SpeakFreely a try, and it seems that it would be much
better if my soundcard driver supports full duplexing.

I see in /proc/asound/sndstat the following:
Sound Driver:3.8.2-980706 (ALSA v0.5.12 emulation code)
Kernel: Linux phiwumbda 2.4.5 #5 SMP Wed Nov 28 18:53:03 CET 2001 i686
Config options: 0

Installed drivers:
Type 10: ALSA emulation

Card config:
Avance Logic ALS4000 soundcard, DSP v3.2 at 0xa400 irq 3
Sound Blaster 16 at 0x220, irq 7, dma 1&5

Audio devices:
0: ALS4000 (DUPLEX)
1: DSP v4.11 (DUPLEX)

Synth devices: NOT ENABLED IN CONFIG

Midi devices:
0: MPU-401 (UART)
1: MPU-401 (UART)

Timers:
7: system timer

Mixers:
0: ALS4000
1: CTL1745

(I'm interested in Card 0 -- I haven't played with Card 1 in years.)

Now, that looks like I have full duplex, right?  Is there anything I
need to do to "activate" it?

(When I compiled SpeakFreely with full duplex and tried to use the
microphone and speakers at the same time, the sound was very choppy --
I suppose that's an indication that I don't have full duplex?)

Thanks for any help you can offer.
--
Jesse Hughes
"[I]t's the damndest thing.  There's something wrong with every last
one of you, and I *never* thought that was a possibility.  But now I
feel it's the only reasonable conclusion." --JSH sees some sorta light

 
 
 

Full duplex soundcard via ALSA?

Post by Vilmos Sot » Sat, 17 Aug 2002 15:58:14



Quote:> I'm giving SpeakFreely a try, and it seems that it would be much
> better if my soundcard driver supports full duplexing.

I also use it and am satisfied with it.

Quote:> I see in /proc/asound/sndstat the following:
> Sound Driver:3.8.2-980706 (ALSA v0.5.12 emulation code)
> Kernel: Linux phiwumbda 2.4.5 #5 SMP Wed Nov 28 18:53:03 CET 2001 i686
> Config options: 0

> Installed drivers:
> Type 10: ALSA emulation

> Card config:
> Avance Logic ALS4000 soundcard, DSP v3.2 at 0xa400 irq 3
> Sound Blaster 16 at 0x220, irq 7, dma 1&5

...

> (I'm interested in Card 0 -- I haven't played with Card 1 in years.)

I use a SoundBlaster 16.

Quote:> Now, that looks like I have full duplex, right?  Is there anything I
> need to do to "activate" it?

AFAIK not. (Well, I didn't touch it for at least 1.5 years.)

Quote:> (When I compiled SpeakFreely with full duplex and tried to use the
> microphone and speakers at the same time, the sound was very choppy --
> I suppose that's an indication that I don't have full duplex?)

You can check the duplex settings by doing the following test:

# cat /dev/audio > /dev/audio

And whatever you talk into the mic should come out around a second later.

Also, you should play an .au file through /dev/audio to make sure
that the sound is ok.

Did you look into the Makefile of speakfreely? It mentions a couple
of things like LINUX_DSP_SMALL_BUFFER and NEEDED_LINEAR. IIRC, I had
to enable these two settings.

Sound Driver:3.8.1a-980706 (ALSA v0.9.0beta4 emulation code)
Kernel: Linux my 2.4.18 #3 Wed May 1 22:14:57 PDT 2002 i686
Config options: 0

Installed drivers:
Type 10: ALSA emulation

Card config:
Sound Blaster 16 at 0x220, irq 5, dma 1&5

Audio devices:
0: DSP v4.13 (DUPLEX)

Synth devices:
0: OPL3 FM

Midi devices:
0: MPU-401 (UART)

Timers:
7: system timer

Mixers:
0: mixer00

Vilmos