[Elecraft] K3 LINE Out mixes KRX3 and main output?

[Leigh L. Klotz, Jr WA5ZNU]

Joe Subich, W4TV wrote:
>> It doubles the data transfer to capture both sound channels 
>> and discard one. 
>>     
>
> Why would you bother to capture both?  Your software should 
> be able to select left, right or mixed input from the soundcard. 
>   

Hmmm...I'm looking at the multi-platform PortAudio v19 API here:
http://www.portaudio.com/docs/v19-doxydocs/structPaStreamParameters.html

Currently, we're using PaStreamParameters::channelCount=1, which doesn't 
offer the opportunity to specify a left or right.
With channelCount=2, we could of course get two channels and discard 
one, as I mentioned.

PulseAudio, which is Linux only, doesn't seem to support it either, but 
I believe ALSA and OSS do.

So, if we use a Linux only solution it's possible to specify 
single-channel capture without discarding one channel, but for the 
cross-platform APIs, it doesn't seem possible. I know you know more 
about sound device manufacture than I do, so maybe you can point us at 
something we've overlooked in PortAudio, so at least we could get 
portable sound capture support for single-channel input.
> Even relatively basic USB sound codecs provide control over the
> input configuration. 
>   
For the device in question, Griffin iMic, this doesn't seem to be the 
case. It does not separate enumerations for independently setting left 
and right input gain. It does support stereo input, just not two 
mic/line gain controls. This seems to be the case on Linux (see 
http://seehuhn.de/pages/imic ) as well as Vista. On Vista, it's even 
worse, and won't capture in stereo at all.

Leigh/WA5ZNU