In June, I presented a paper at the IASPM conference in Halifax. At the conference, my colleague from the University of Toronto at Scarborough, Dr. Alan Stanbridge, presented a paper on the new generation of jazz musicians successfully engaging with current pop music. One of the examples that he gave of the previous generation's quite unsuccessful engagement with contemporary pop music was Frank Sinatra's cover of Petula Clark's "Downtown." Stanbridge suggests that disgust seems to be evoked by Sinatra's voice, a disgust with the mainstream rock or youth music, or the synthesis of pop and jazz, that Sinatra was performing.
I wonder if something else is happening here. Morrissey does something similar vocally, recently, especially in live performance. I wonder if it is a kind of ironic self-reference rather than a kind of statement against the mainstream (unless it is perhaps a kind of self-reference that is in fact of distaste because he is performing that particular music). In any case, I read Sinatra's performance as an aural gesture which refers to the singer rather than explicitly the mainstream.
I should mention that Sinatra's performance (with its "barfy" sounds) is full of wonderful musical moments, however cheesy the performance might be. It is now one of my favourite recordings.