It's a very technical performance, lots of glimpses and witty lines thrown away in a lower vocal register.

A vocal register is a series of tones which are produced by a certain position of the larynx, tongue and palate.

Some later Romanticists, therefore, such as Spohr and Mendelssohn, came back immediately to the comfortable middle register as the real vocal register of song.

People ask whether there are such things as vocal registers.