Cutting through the noise: do vibrato and formant shaping affect vocal detection?
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Authors
Becz, Elizabeth
Issue Date
2025-08
Type
Electronic thesis
Thesis
Thesis
Language
en_US
Keywords
Architectural sciences
Alternative Title
Abstract
Opera singers must project a single, unamplified voice above a full orchestra in halls whose reverberation commonly exceeds two seconds. Classical pedagogy credits two techniques with making this possible: vibrato—a 5–7 Hz modulation of fundamental frequency and amplitude—and formant shaping, which concentrates energy into a narrow “singer’s formant” near 3 kHz where orchestral spectra are sparse. The present thesis measures how strongly each technique contributes to audibility. A laboratory detection experiment asked six trained listeners to adjust the level of sustained vowels embedded in a steady orchestral chord. Among the four vocal conditions (±vibrato × ±formant shaping), vibrato alone produced the largest benefit, lowering thresholds to –36 dB for /A/ and –38 dB for /E/ relative to the mask. Formant shaping alone, by contrast, left /A/ unchanged and raised the /E/ threshold by roughly 6 dB. To examine whether these perceptual trends translate to production practice, four professional audio engineers mixed operatic phrases against the same orchestral texture in a constrained ProTools session. The clip gain applied to the vocal track served as a real-world proxy for the level boost required to achieve clarity. Engineers needed the smallest boost—only 4.8 dB—when formant shaping was present without vibrato, suggesting that the 3 kHz energy peak provides a spectral “handle” even though it yielded no advantage at the detection stage. Taken together, the findings show that vibrato enhances initial detectability, whereas formant shaping improves mix efficiency once the voice has been perceptually segregated. Although the study draws on a small sample (six listeners, four engineers, one singer, one orchestral chord), the convergence between laboratory and studio settings indicates that these techniques address complementary phases of the auditory-masking challenge.
Description
August2025
School of Architecture
School of Architecture
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY