Dumb question: Why CD-R/DVD incompatibility?

[KyleB]

I have a Toshiba SD-2109 DVD player, and it, like some other DVD players, will not play CD-R's as audio CDs. This is not a complaint--I knew about it when I bought it & it doesn't bother me. I'm simply curious as to WHY this is the case, since I've seen it listed as an issue for a number of DVD players, and I've never seen any audio CD players that don't handle CD-R's. Is it strictly a hardware issue? Cost-cutting? or what?

[X]

I believe it's the laser wavelength and focusing being just a little off between DVD and CD. Commercial CD's have much higher reflectivity than CD-R so they work. Funny though, sometimes CD-RW will work where CD-R won't. My Sony is that way.

[twikoff]

alot of dvd drives actually have it in the specs that a cdrw will work, but not a cdr