Jazz fluegel hornist Chuck Mangione has become so popular that he now has very own TV commercial. The ad features Ella Fitzgerald attempting to decide whether the music she is hearing is Chuck Mangione playing or merely a tape. And guess what? Ella can't decide.

Last night at the Merriweather Post Pavillon Mangione, accompanied by his back-up group and a brass section, played before an overflow crowd that seemed to swoon at his every note.

His show was a technical masterpiece. Each of the musicians displayed extraordinary skill, faithfully reproducing his songs without a slip. The songs themselves wafted across the pavillon, the cool harmonies and sprightly rhythms soothing the excited listeners. Mangione presented his most popular tunes including "Land of Make Believe" and the overture from the movie sound track for "The Children of Sanchez." The set went perfectly.

The problem is that perfection tends to become monotonous after a while. Mangione's musical expertise carries with it certain liabilities such as a lack of spontaneity and feeling and his music often sounded mechanical, like the cold, taped Muzak which drones from the speakers at shopping malls. Mangione and his group were so precise that they began to sound exactly like their records, and by the end of the show one was tempted to ask: was it Mangione or was it Memorex?

What's the difference?