In stage acoustics research, it is common to use virtual acoustic environments over headphones to simulate various room conditions for musicians. When experiments are conducted in suboptimal physical environments (e.g., withoutan anechoic chamber), it is often challenging to reduce the inherent reverberation of the test room while ensuring that musicians can hear their own direct sound through the headphones as if the headphones were transparent. In the present study, two methods were developed and tested using an acoustic dummy head, with the aim of faithfully replicating the direct sound of a solo singer over a pair of closed-back headphones. The results showed that the first method - creating and applying an exact finite-impulse-response (FIR) filter - may lead to undesirable effects, primarily due to the inherent delay of the playback system. The second method, which utilized a multiband equalizer, proved more effective when evaluated with stationary broadband noise. For non-stationary, real-world sounds such as singing and speaking voices, the comparison between the reference sound and the signal processed by the multiband equalizer remained reasonably accurate, with differences typically less than ~1 dB across much of the frequency range. Future work may further refine and evaluate the proposed methods through listening tests.

Choir spacing—the physical arrangement and distance between singers—is known to influence both ensemble sound and individual singing experience. However, systematic perceptual studies remain limited due to the challenges of conducting controlled experiments with full choirs. This study presents a virtual acoustics system designed to investigate spacing effects under repeatable and controlled conditions. Anechoic recordings were combined with binaural room impulse responses (BRIRs) simulated in Room Acoustics for VirtualENvironments (RAVEN) to recreate a concert hall environment. In each session, one participant sang live with spatialized pre-recorded choir voices rendered over closed-back headphones, with EQ compensation applied to their own voice. Thirty-nine experienced choir singers performed under three spacing conditions: Close, Lateral, and Circumambient. After each condition, participants completed a questionnaire assessing perception of self and others, vocal production, and overall preferences. Results indicated that spread formations (Lateral and Circumambient) significantly improved self-monitoring and tuning. Perception of other sections showed mixed results and was not consistently affected by spacing. Vocal effort ratings did not differ significantly, while vocal technique adjustments were border-line significant, with greater adjustment reported in the closer formation. Most singers preferred spread formation for concert settings. The study demonstrates the feasibility of using virtual acoustics to explore spacing effects in choral performance.