title: Curbing-The Metallic Mode In-between: An empirical study qualifying and categorizing restrained sounds known as Curbing based on audio perception, laryngostroboscopic imaging, acoustics, LTAS, and EGG.
abstract: OBJECTIVE
  This study aims to study the categorization Curbing from the pedagogical method Complete Vocal Technique as a reduced metallic mode compared with the full metallic modes Overdrive and Edge by means of audio perception, laryngostroboscopic imaging, acoustics, long-term average spectrum (LTAS), and electroglottography (EGG).
  
  
  METHODS
  Twenty singers were recorded singing sustained vowels in a restrained character known as Curbing. Two studies were performed: (1) laryngostroboscopic examination using a videonasoendoscopic camera system and the Laryngostrobe program; and (2) simultaneous recording of EGG and acoustic signals using Speech Studio. Images were analyzed based on consensus agreement. Statistical analysis of acoustic, LTAS, and EGG parameters was undertaken using Student paired t tests.
  
  
  RESULTS
  The reduced metallic singing mode Curbing has an identifiable laryngeal gesture. Curbing has a more open setting than Overdrive and Edge, with high visibility of the vocal folds, and the false folds giving a rectangular appearance. LTAS showed statistically significant differences between Curbing and the full metallic modes, with less energy across all spectra, yielding a high second and a low third harmonic. Statistically significant differences were identified on Max Qx, Average Qx, Shimmer+, Shimmer-, Shimmer dB, normalized noise energy, cepstral peak prominence, harmonics-to-noise ratio, and mean sound pressure level (P ≤ 0.05).
  
  
  CONCLUSIONS
  Curbing as a voice production strategy is statistically significantly different from Overdrive and Edge, and can be categorized based on audio perception. This study demonstrates consistently different laryngeal gestures between Curbing and Overdrive and Edge, with high corresponding differences in LTAS, EGG and acoustic measures.
authors.affiliation: Department of Business Communication, Aarhus University, Aarhus, Denmark. Electronic address: mat@bcom.au.dk.
authors.forename: Mathias Aaen
authors.initials: MA
authors.lastname: Thuesen
authors.affiliation: Department of Otorhinolaryngology, Queen's Medical Centre Campus, Nottingham University Hospitals, Nottingham, UK.
authors.forename: Julian
authors.initials: J
authors.lastname: McGlashan
authors.affiliation: Complete Vocal Institute, Copenhagen, Denmark.
authors.forename: Cathrine
authors.initials: C
authors.lastname: Sadolin
mesh_terms: D000162:Acoustics; D000328:Adult; D001307:Auditory Perception; D004568:Electrodiagnosis; D005260:Female; D006801:Humans; D007600:Judgment; D007828:Laryngoscopy; D007830:Larynx / Q000000981:diagnostic imaging* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012815:Signal Processing, Computer-Assisted; D063346:Singing; D013018:Sound Spectrography; D049489:Stroboscopy; D014833:Voice Quality; D055815:Young Adult
keywords: Audio perception; Complete Vocal Technique; Curbing; Laryngostroboscopic imaging; Long-term average spectrum