[Skimmertalk] CW skimmer audio output stutters under load

bubnikv . bubnikv at gmail.com
Thu Aug 6 05:47:38 EDT 2015


Hi gang.

I am having issues with the CW skimmer audio output. I am running the CW
skimmer on a 2007 top notch laptop with an external USB Sound Blaster X-Fi
sound card. The laptop seems to be just adequate to run the CW skimmer on
40m at 96 ksamples per second. The skimmer decodes all right and I see no
glitches on the waterfall. But when I enable the audio output, I hear quite
a lot of glitches once the CW skimmer activates around a hundred of
decoders. MME or WDM does not make a difference. I am using the drivers
from Creative. I tried to lower the maximum amount of decoders in the CW
skimmer preferences, but it does not seem to make a difference.

I get similar audio glitches with the Rocky software on the same hardware
once the computer CPU is loaded. When running the Rocky software on the
foreground as the only application, the audio is perfect. This all
indicates, that the length of the audio output buffer used by the CW
Skimmer is too short for the accumulated latency of my aging laptop. I
suppose Alex keeps the sound input / output buffers as short as possible to
keep the latency low. But this does not work well with my aging laptop and
the USB sound card.

Is there a way around it? Is there a way to increase number of sound output
buffers?

Thanks and VY 73,
Vojtech OK1IAK, AB2ZA


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