The normal range of the SYNTHOPHONE can be extended through the use of the F#-trill and low-C-keys respectively as additional OCTAVE KEYS.
The F#-trill can be used as an additional OCTAVE-UP-KEY when playing in the range above high F. Simply play another octave using standard fingerings, but hold down F#-trill in addition. Note, that the regular F#-trill-key function is retained for F to F#.
The right hands C-key can be used as an additional OCTAVE-DOWN-KEY to reach below Bb. Simply hold down this key while playing normal fingerings down to low E. This extends the low range by 6 half-steps. Note, that below E, the the key is a regular C-key.
M U S I C A L   A P P L I C A T I O N S 
-The top octave feature will allow you to play easily in the range of a flute part, avoiding difficult altissimo fingerings.
-The low octave feature provides for low notes in the clarinet range.