Maybe the grooves are deeper.......

I think some consumer-grade stand-alone audio CD recorders will only work with blanks marked "music".

20 years ago when you bought a blank cassette tape, part of the price was a fee paid to RIAA (or similar body) - working on the assumption you were using the blank tape in a dual-well cassette deck to steal material from a copyrighted tape. I think this "music CD" thing (which has mostly failed) is their attempt to relive the good old days when they had everybody by the short ones. As someone who has used a lot more tape to make music that duplicate music, it always ticked me off.

A CD IS a CD, but there are slight performance differences in color. I've read that varying amounts of heat build up occur in the player with darker and lighter disc surfaces. (you'll notice a lot of video game discs are dark) A friend of mine used to use CDRs that were black somehow relative to all of this. In which case, it seems to me the disc would get warm because it would reflect less heat back into the player. But if the disc retains the heat doesn't the player still warm up? That heat has to go somewhere. It seems an excessively hot CDR would start to corrupt the data - since it was the heat of a laser that put the tiny dot on the CDR in the first place. A video game disc would be stamped and not burned, so data corruption wouldn't be a factor on a manufactured black disc. But as far as black CDRs, someone would have to show me some evidence to convince me there's a difference.

A slight digression:

A friend of mine asked me the other day whether or not the CD from professional production plants are different from CD-R's? I am thinking of buying a robotic CD copier so that I can actually provide a CD production service, and I had never thought about it like my friend put it.

Is there a difference?

Yes. The CDs from a professional plant are CD-ROMs, and they are produced using a glass master which creates the die to stamp the pits & grooves. A CD-R is "burnt" using a laser to draw the pits & grooves. For a simplistic explanation.

I see.

I guess getting an injection moulding machine might be a bit heavy for an on-the-side service. I'll probably stick with the robotic CD-r burners. I'm guessing there is a serious difference in life expectancy and quality of CD-R's and CD-ROMS?

Yes. plus to make a glass master you need some hermetically-sealed 'clean grade 100' or some such room. Most people who say they do it, actually farm it out. For example to my knowledge there are no glassmastering plants left in the UK as they all went bankrupt. I use 10-20 different companies for CD reproduction and 99% of the time its farmed out to what I think is a BMG plant in France.