[Skimmertalk] CW skimmer audio output stutters under load

Bob Wilson, N6TV n6tv at arrl.net
Fri Aug 14 11:11:51 EDT 2015


On Thu, Aug 6, 2015 at 2:47 AM, bubnikv . <bubnikv at gmail.com> wrote:

> I am running the CW
> skimmer on a 2007 top notch laptop with an external USB Sound Blaster X-Fi
> sound card.
>

On Fri, Aug 14, 2015 at 2:57 AM, bubnikv . <bubnikv at gmail.com> wrote:

> The internal sound card is mono only and it does not even support WDM. The
> USB ports support 2.0.
>

I'm confused.  Which sound card are you using, the external one or the
internal one?

As far as I know, there is no such thing as a "mono" sound card.  Most
sound cards do have a mono MIC input, but I thought all modern PC sound
cards had stereo speaker outputs.

Note that CW Skimmer intentionally outputs phase-inverted stereo (left and
right channels have inverted polarity).  If you listen to CW Skimmer with
stereo headphones, the audio will not be "centered" in your head.  I asked
Alex about this 6 years ago, and he said "I have special code that inverts
one of the audio channels, to avoid the sound in the center of the head and
make listening easier."  Personally, I find it unpleasant to listen to, and
I wish he would add an option to turn that off.

If the right audio channel is shorted to ground by a mono plug, I'm not
sure what effect that could have (maybe none).

I should note that CW Skimmer has never produced super clean audio output
for me, especially when the CPU is busy.  MME output always sounds better
than WDM.  But there are always ticks and pops no matter what you do.

Note that CW Skimmer was designed for automated spotting, not for hi-fi
listening.  I suggest muting the skimmer audio output using the button on
the CW Skimmer toolbar, then and use a real receiver controlled by
BandMaster, N1MM+, Win-Test, etc. to listen to signals.  Use CW Skimmer to
feed spots to these programs via the built-in telnet server, and click on
spots in the band map to move your real receiver to the spot frequency.

73,
Bob, N6TV


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