Many extended techniques can be performed on the bassoon, such as multiphonics, flutter-tonguing, circular breathing, double tonguing, and harmonics. In the case of the bassoon, flutter-tonguing may be accomplished by "gargling" in the back of the throat as well as by the conventional method of rolling Rs. Multiphonics on the bassoon are plentiful, and can be achieved by using particular alternative fingerings, but are generally heavily influenced by embouchure position. Also, again using certain fingerings, notes may be produced on the instrument that sound lower pitches than the actual range of the instrument. These notes tend to sound very gravelly and out of tune, but technically sound below the low B.