Re: playing 4 channels

[Takashi Iwai <tiwai@suse.de>]

Hi Helmut,

At Fri, 11 Oct 2002 11:53:42 +0200,
Helmut Obertanner wrote:
> 
> how is that with other cards, is the mastervolume also respoonnsible for the 
> rearchannels ???

it depends.  the later models of cmipci support 4/6 channels playback
via one DMA, i.e. interleaved output.  in this case, the output volume
is controlled by a master volume.

in the case of SB live, the rear output has different codec without
volume controls, but the emu10k1 dsp itself can attenuate the signals
inside.

most of other sound chips use AC97 for the rear volume controls.
some use the secondary codec, and some use a 4/6 channel-capable
codec.  in both cases, the "Surround" volume element will be there.

 
> another problem:
> in another thread i want to record, (for the realtime vocoder / FX on 
> microphone)
> 
> opening the device fails with: device busy.
> i use another pcm_handle for capture.
> 
> is it impossible to record while playing ?
> or what i'm doing wrong...

the rear output uses the ADC as the secondary DAC.  so, you cannot use
ADC together with 4 channel outputs.  (again, the later models use
only one DAC for interleaved 4/6 mode, and it's no problem.)


ciao,

Takashi


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