Skype and sound

I'm trying to get Skype (Internet-telefony) working properly.
Reception is fine, but my counterpartners hardly hear me.
In Kmix MIC is at maximum and the red button switched on.
I hear myself loudly through the speakers, but I am Hardly heared.
Settings under soundsystem are:
ALSA; full duplex, sample rate 48000 HZ, standard quality,
soundsystem active, realtine priority, 8 fragments 2048 bytes.

Does anyone have an advice how to enhance the volume of the microphone ?

Thanks,

Rene