Karaoke via computer

DMara
DMara Posts: 1,434
edited July 2010 in Electronics
This is my set up:
  • Small desktop with a Sound Blaster X-Fi Platinum sound card (this desktop holds over 5000 karaoke songs under VOB format (DVD format).
  • Yamaha Laser Disc Karaoke player which has two microphone connections
  • Denon AVR-4810 receiver

So I hooked the computer sound card to the Yamaha Karaoke Line-In via RCA red-white cable, then from the Yamaha Karaoke Line-Out to the Denon AVR also via RCA red-white cable. Unfortunately, the sound output was quite unpleasant at this point :(

What do I need to do to improve the set up?
Is there a computer device, either internal or external, that can help me plug the two microphones directly in to the computer, and thus help eliminate the use of the Yamaha Laser Disc Karaoke player? (Keep in mind that these microphones are not those tiny computer microphones, but are real on-stage microphones).
Do I need an external DAC at all?
Any suggestion is quite appreciated :)
Gears shared to both living room & bedroom:
Integra DHC-80.3 / Oppo BDP-105 / DirecTV HR24 DVR /APC S15blk PC-UPS
Living room:
LSiM707's / LSiM706c / LSiM702 F/X's / dual JL Audio Fathom F113's / Parasound Halo A51 / Panasonic 65" TC-P65VT50
Bedroom:
Usher Dancer Mini 2 Diamond DMD's / Logitech SB Touch / W4S STP-SE / W4S DAC-2 / W4S ST-1000 / Samsung 52" LN52B750
Other rooms:
Audioengine AP4's / GLOW Audio Sub One / audio-gd NFB-3 DAC / Audioengine N22
audio-gd NFB-10.2 / Denon AH-D7000