CPPS and Voice-Source Parameters: Objective Analysis of the Singing Voice

Abstract

In recent years cepstral analysis and specific cepstrum-based measures such as smoothed cepstral peak prominence (CPPS) has become increasingly researched and utilized in attempts to determine the extent of overall dysphonia in voice signals. Yet, few studies have extensively examined how specific voice-source parameters affect CPPS values. Objective. Using a range of synthesized tones, this exploratory study sought to systematically analyze the effect of fundamental frequency (f o ), vibrato extent, source-spectrum tilt, and the amplitude of the voice-source fundamental on CPPS values. Materials and Methods. A series of scales were synthesised using the freeware Madde. Fundamental frequency, vibrato extent, source-spectrum tilt, and the amplitude of the voice-source fundamental were systematically and independently varied. The tones were analysed in PRAAT, and statistical analyses were conducted in SPSS.Results. CPPS was significantly affected by both f o and source-spectrum tilt, independently. A nonlinear association was seen between vibrato extent and CPPS, where CPPS values increased from 0 to 0.6 semitones (ST), then rapidly decreased approaching 1.0 ST. No relationship was seen between the amplitude of the voice-source fundamental and CPPS. Conclusion. The large effect of f o should be taken into account when analyzing the voice, particularly in singing-voice research, when comparing pre and posttreatment data, and when comparing inter-subject CPPS data.

Wearable Neck Surface Accelerometers for Occupational Vocal Health Monitoring: Instrument and Analysis Validation Study

“…Among all NSA-derived metrics across phonation tasks, only CPP and Tilt from the Rainbow Passage most closely mirrored the temporal trends of the SAVRa with significant changes over time in both genders. These results are encouraging as CPP is already regarded as a robust measure of vocal fatigue and voice deviation with air acoustic microphone signals [ 35 , 36 ]. Even though our NSAs have more restricted bandwidth (around 3 kHz), the clinical robustness of CPP seemed to be preserved.…”

It Sounds like It Feels: Preliminary Exploration of an Aeroacoustic Diagnostic Protocol for Singers

“…Nineteen singers volunteered for participation (soprano [7], mezzo-soprano [1], alto [1], tenor [4], baritone [5], and bass [1]). The mean SVHI-10 score (M = 10.89; SD = 5.28) was higher than norms recorded by Sobol et al [79], and one participant disclosed a history of diagnosed vocal injury.…”

“…As CPPS is robust to factors such as environmental noise and microphone selection [38], it may be a useful clinical tool for tracking subtle changes in the singing voice. After controlling for the effects of f o and intensity [7,39], a decrease in CPPS values may be associated with elevated EASE subscale scores.…”

“…The CPPS was calculated in PRAAT v.6.2.16 [61] using the 'To PowerCepstrum' and 'Get CPPS' functions as described in earlier works [9,71,72]. All settings were kept as standard [61] apart from 'Peak search pitch range (Hz)' which was increased to 1000 Hz to ensure the f o of all tasks were well accommodated [7]. The RAP and APQ3 were obtained in the 'voice report' function of PRAAT using standard settings.…”

“…For voice researchers, clinicians, and pedagogues, singing-voice analysis presents unique challenges. Many of the widely used voice assessment techniques (e.g., local pitch and amplitude perturbation measures) rely on methods that may not be robust to singingvoice variables such as wide ranges in f o , intensity, or vibrato characteristics (e.g., [5][6][7][8][9]). Additionally, traditional clinical voice analysis tasks (e.g., sustained vowels and reading passages at a comfortable pitch and intensity) do not incorporate the singing voice or consider singing-specific phenomena such as registration events or vibrato characteristics.…”