choiropractor
A physical-therapy doctor who manually aligns your windpipe and vocal chords for perfect singing-pitch and airflow control.
If da teenage delinquent who hadda "face da music" by listening to his horridly-off-key-voiced mom sing "America The Beautiful" on da court karaoke had asked said female parent to go see a choiropractor first, perhaps her vocal rendition of said patriotic ballad might have been a bit more palatable for him to endure.