Clever opening line to your post! LOL.
A minor point first: I believe that should be CDR-W1500, not DCR-W1500.
I'm not 100% certain, but I believe the reason the unit won't work with cd-r's that are not designated as being for audio is NOT due to any speed issues. I believe the reason is that built into the cost of the audio-designated cd-r's is a royalty provision intended to compensate the recording industry for the monetary losses which they presume each copy results in. And to enforce that provision, cd recorders (as opposed to computers) are designed to work only with disks that indicate to the recorder that they have that designation.
My suspicion is therefore that current disks that may have higher speed ratings than those which existed when the machine was designed will work fine, as long as they are designated as being for music/audio.
Regards,
-- Al