Stopped Horn (Gestopft) Transposition & Mute Pitch Compensator
Stopped Horn & Mute Compensator
Stopped Horn & Mute Pitch Shift CompensatorSeal palm firmly against the bell rim to prevent air leaks for a brassy, raspy buzz. When seeing + or Gestopft, transpose down a half-step.
The Stopped Horn Paradox: Why Sealing the Bell Raises Pitch by a Half-Step
Many beginners assume that inserting the hand deep into the bell lengthens the tubing and should flatten the pitch. However, modern acoustic waveguide physics confirms the opposite:
When the palm hermetically seals the bell, the acoustic open-end displacement antinode is forcibly terminated inside the hand. The instrument becomes an effectively shortened closed-pipe air column. The effective standing wave length is shortened by ~15-20cm, shifting the resonant modal frequency exactly one half-step (+100 cents) higher!
Conclusion: When encountering a (+) or Gestopft mark, fully seal the bell and transpose your fingerings down one half-step!