Optimising intonation and playability in a vented trumpet: Acoustical behaviour and performer insights

Sound is produced in a brass instrument by the vibration of the player's lips at the input end and radiates through the bell at the exit. Typically, these are the only two openings in brass instruments. In a vented trumpet, additional holes are drilled into the sides of the tube. The player can open or close these holes to improve the instrument's intonation and stability, particularly in baroque performances. This paper studies the acoustical behaviour of the vent holes in a four-hole vented trumpet. The input impedance is measured using the BIAS system for two frequently used venting fingerings. These experimental results are compared with numerical simulations using the Openwind framework, with input data derived from mechanical measurements of the bore profile of the trumpet. An optimisation method based on the input impedance is proposed for the trumpet, varying the physical size and position of the holes. A new tube with holes is built based on these modifications. A professional player of the vented trumpet has provided feedback on the effect of the modifications on the intonation and playability of the trumpet, revealing a clear relationship between resonance amplitude and lip behaviour for all vent holes studied.