The acoustic impedance (Z) spectra of different horns with different mouthpieces, players’ hands, mutes, fingerings and the combinations of these were studied, as were the effects on the output sound of the horn of filtering the auditory feedback provided via headphones to players ranging from professionals to students. Accurate replicas of horn players’ hands in playing position were used for extensive and precisely repeatable measurements of the impedance spectra at the horn input. Differences in impedance spectra due to hand size, shape and position in bell were greatest for resonances above the cutoff frequency of the bell (about 500 Hz). Mutes affected the frequency of the resonance peaks, especially around 350 to 400 Hz (corresponding to the horn’s middle register). For practice mutes, resonances were up to 100 cents flatter than with hand in bell.
Players’ reports of the playability with different hands and mutes are qualitatively explained in terms of differences measured in the impedance spectra. Statistically significant correlations were found with players’ perceptions of quality of sound for the different hands and ease of playing for different practice mutes. No statistical differences were found between players’ ratings of playability for three different stopping mutes, which showed relatively similar impedance spectra. Practice mutes decreased the sound level by 10 dB without a large change in the spectral centroid. Stopping mutes increased the spectral centroid from less than 1 kHz to more than 3 kHz without affecting the sound level.
The horn radiates high frequencies better behind the player. Consequently, the presence and type of reflecting surfaces affect the sound received by the player. Horn players are sometimes concerned by such changes and how this affects their playing. When spectrally altered auditory feedback was provided to horn players, relatively little change in output spectra was measured. The wearing of headphones resulted in changes to the sound for some players, independent of the auditory feedback received. Players’ hand movements in the bell were video recorded and different types of movement were identified: movement in response to changes in auditory feedback, extra-musical movements, and movements associated with intonation.
|Qualification||Doctor of Philosophy|
|Publication status||Unpublished - 2011|