Bourdon (bell)

The bourdon is the heaviest of the bells that belong to a musical instrument, especially a chime or a carillon, and produces its lowest tone.

Cast in 1929 as part of the Rockefeller Carillon, it weighs 19,000 kg (41,000 lb) and measures 3.10 m (10 ft 2 in) across.

As it is not a part of a harmonically-tuned set, the Olympic Bell is not considered a bourdon.

[2] Although carillons are by definition chromatic, the next bell up from the bourdon is traditionally a whole tone higher in pitch, leaving a semitone out of the instrument.

Bells separated from the next higher note by more than two semitones (one whole tone) are called sub-bourdons.