Man, how times have changed.

Years ago I was hired to sing a number of jingles in Dallas TX...on one occasion the guy from the ad agency who was "producing" had me sing his 30 second spot over and over and over....this went on for like two hours straight. I tried everything I could think of, different approaches, etc. Finally, the recording engineer (who was a friend and had recommended me) said to the guy "Could you tell us exactly what you're looking for?" and the ad guy responded with "Yes....something that doesn't suck."

I'm probably really old school (or just old), but I kind of feel like if you put yourself out there as a professional vocalist for hire, you need to be prepared for the critiques that come with it, as harsh or terse as they may be. I probably would say something to the effect of "I appreciate your taking the time & effort on this, but I don't feel that your vocal is a good fit for this particular recording. Thanks anyway."

** Disclaimer, I'm the kind of person who likes hearing the truth, regardless of how tough it can be to hear it. Most people probably aren't that way.