Performance Change in Vocalists with Variation in Headphone Foldback and Reverberation Level

It is well known amongst the classical singing community that the acoustic of the performance space has an impact on the performance given by a singer. Relationship between acoustic environment and performance have been discussed by a number of authors [1], [2],. The level of reverberation, critical distance and proximity to reflecting surfaces have all been shown to have impact on parameters such as timing, volume and tone [3], while occlusion of the ear (preventing the singer getting auditory response from their own voice) has significant impacts on loudness and pitch intonation.

In the popular music field, performance and recording generally takes place in acoustically dry environments, in which reverberation time is low (typically around 0.3s). Performers also often perform and record to backing tracks in which the accompaniment is fed through headphones. In order to prevent problems caused by occlusion of the ear by the headphones, the performer’s own voice is generally sent back to them through the headphones (known as foldback). Given that the acoustic feedback of their own voice to the performer has a substantial impact on performance, this means that variations in this foldback, such as level and use of reverberation effects could have a substantial effect on the popular music performer. Understanding this variation is important both to enable performers to improve their performance when in a situation requiring headphone foldback, but will also be essential for the understanding of new ‘virtual’ acoustic spaces being developed for music rehearsal [4]

This study assessed the impact of variation in foldback of both voice level and reverberation depth to a group of singers from both the popular music and classical traditions, in order to assess whether this variation impacted on their performance, and whether familiarity with foldback systems affected any level of performance change.

Results from the pilot study indicated that singers underwent significant changes in level, pitch, intensity, vibrato depth and performance tempo with the changes in acoustic foldback. In particular, average sound pressure level increased with a strong correlation to reverberation ‘wetness’, while pitch correlated strongly with foldback level. Low levels of foldback caused singers to go flat, while high levels caused them to go sharp. While dynamic range varied considerably with recordings there was no clear correlation with any of the parameters.