Oscillatory Mechanism of the Glotis in Horn Playing

Introduction

The connection between singing (and vibration of vocal chords) and playing the horn or other brass has occupied some writers’ attention for some time. Altenburg (1795) considered singing indispensable in the study of the trumpet (Knodt 1973). Recent publications have stressed the analogy between the breathing and articulation mechanisms for singers and horn and trumpet players (Knodt 1973, Saxton 1975, Orval 1978). Damsté (1966) and subsequently Leno (1974) have also shown experimentally the resemblance between the vibration of vocal chords while phonating and the vibrations of lips a trombonist’s lips while playing.

The voluntary and active participation of the vocal chords when playing is used for the production of special acoustical effects (chords). This is the case in the Weber Concertino for horn, op. 45 (1806) and in several contemporary works. The note sung is never the note played, but presents with the latter a determined harmonic relationship, and always results from a voluntary act of the performer (Sluchin, 1981).

On the other hand, involuntary participation of the vocal chords when playing the horn normally, particularly during the attacks, is not widely known. The performer is unaware of this and an observer cannot see it, so it can only be investigated effectively by an objective and non-invading technique, that is to say, one which does not disturb the performer’s natural movements, or does so only in a minimal way.

The present article recognizes this phenomenon and describes the observations made with three professional horn players of both sexes, with the aid of an electroglottograph during the emission of different standardized instrumental sounds.

Material and Methods

For the experiments described in this article we have used:

1. An electroglottograph of which the characteristics have been published (Dejonckere, 1981), and which is habitually used for experimental and clinical work in order to investigate the vibratory mechanism of the vocal chords.

The output of the electroglottograph is a function of the electrical impedance across the anterior part of the subject’s neck, between two skin-electrodes placed on either side of the thyroid cartilage. A high-frequency low-voltage current (not perceived by the subject) is sent through the larynx. Current flow is proportional to the area of electrical contact between the vocal chords, which alternately increases and decreases during normal phonation (Lecluse, 1977).

The relation between specific phases of the vibration cycle of the vocal chords and precise events of the electroglottogram were investigated by means of ultra-high-speed cinematography in vivo (Van Michel and Coll, 1970), stroboscopic photography in vitro (Lecluse, 1977) and stroboscopic laryngoscopy in vivo (Pedersen, 1977).

1. A microphone, Ampex 2001.
2. A polygraph (Elema-Schönander) which allows the observation, in real time and linearly, of periodic phenomena up to 1250 Hz. The speed of the passage of the paper was 50 or 100 cm/sec. The electroglottogram of the performer and the horn sound oscillogram were inscribed simultaneously on two different channels. A third channel was used for time indication.
3. Three horns: Holton type H-179 double descending; Alexander, double with ascending third valve; Selmer, compensating with ascending third valve.

The experiments were performed on three professional hornplayers, one female and two males.

Five characteristic notes were investigated, covering a large part of the usual range of the instrument. (See following chart.)

Most of the graphic recordings were realized with ‘‘forte’’ notes, accented or sustained, and with a normal attack, as well as ‘‘sforzandi’’ and ‘‘staccati’’.

For reference, some recordings were made with the hornist singing and playing simultaneously.

142 graphic recordings were obtained and analyzed.