1. Cable connections checked from behind? On proper port? or on Mic?
2. Audio Midi Setup set with appropriate speakers? Performed Speaker Test?
3. Speakers Powered ON? Power Cables checked?
4. HeadPhones plugged in resulting in Mute?
5. Any other drivers conflicting? OnBoard Audio disabled in BIOS? (Onboard drivers for Azalia / AppleHDA known to conflict)
6. Is Device's name mentioned properly in Audio Midi setup? eg. "kX 0350 etc" (Application \ Utilities)
7. "Intel ICH and PIIX Controller" was enabled in your iDeneb setup? unchecked Azalia, AppleHDA in setup?
8. Volume Controls checked?
9. Earlier versions working on your system? (have you tried earlier versions? see my signature for download links)
10. Your sound works on XP/Vist???? (and with kX drivers for Windows???)
11. BIOS shows information that PCI card is inserted properly?
12. Tried other Distros such as Kalyway itself?

iDeneb was shown in the main page and replaced with JaS release, why?

13. Sound comes when you put your headphones ON? in the headphones port?
I'm assuming you've already read the release notes, new known issues and meaning of "BETA" on web properly