Most karaoke hardcores use CD's for backing tracks (Karaoke tunes). Affordability of good quality mics and music reproduction system popularity favors the use of CD's or mp3's over tapes. Nonetheless, they are still typing it in search engines the same way we still say "record label" instead of CD label to denote a company producing music.
I like singingmachines and I would want to buy it if I were an electronics store and wanted to push karaoke tape (err.. CD) players. I imagine your elctronics-related domain arsenal is well-stocked up by now and the word is geting out. This should give you the marketing edge you need to maximize your reselling profits.
Good luck
