"I used to have a problem before with not being able hear sound after entering KDE on my old debian system, but all I had to do then was to make some changes in KDE's soundsystem. Even though the problem I have now shows the same characteristics as the old one,"
Key phrases:
"after entering KDE"
"same characteristics as the old one"
Hmmm, KDE, huh? What does that tell you?
Does that mean you had sound in Gnome or any window manager, but not in KDE?
I couldn't see any mention of your kernel, which one are you using? 2.4 or 2.6? Are you on Sid? Have you checked the BTS (debian bug tracking system)?
I will asume you installed your sound module with modconf, installed sndconfig and configured it, and installed aumix and calibrated the sound, and as you said, you belong to the audio group.
check this page:
Unofficial #debian channel FAQ on freenode
http://www.linuks.mine.nu/debian-faq-wiki/
If it doesn't help, and no angel comes from heaven to save you:
1. you still can do a search on this site.
2. check with the boys at the #debian on the IRC, (Freenode server), they are pretty good, but i would advice you to change your attitude.
3. also with the boys at #debian-kde and #kde on the IRC.
4. you can look at the archives of the debian users mailing list at debian.org.
5. any forum from kde.org
good luck