Poor sound from microphone with Asrock onboard sound
 

The sound from my microphone is very poor in Mandrake 10 - I have onboard sound AC'97 on Asrock K7S8X motherboard. I can hear the sound played by applications very well but when I use Skype and test the sound, its quality is very poor, very low volume and practically all higher frequencies are cut off. Even without Skype when I listen to myself through the microphone the sound isn't good. On Windows the sound is perfect so there must be something with my setup. Well, in Windows I have an option "Microphone boost" in volume control, perhaps that is what is needed, but there's no such option in Mandrake volume control. What can I do about it?