Phonatory System: Acoustic/Perceptual Characteristics of Voice (EXAM 2) Flashcards
Glottal Spectrum
Influences the distinctiveness of voiced sounds we hear based on Fundamental frequency
Complex sounds: F0 and its harmonics together create a complex sound”
Sound produced by glottal vibrations at larynx is complex buzzing sound made up of F0 and its harmonics
Harmonics
Whole number integer multiples of F0
Adult male glottal spectrum
-12dB/harmonic
decreasing in intensity as we increase harmonic number
120Hz difference between each harmonic
CLOSER spacing because of lower F0
Leads to more intense/distinct sound
lower the pitch, more distinct
Adult female glottal spectrum
-12dB/harmonic decreasing in intensity as harmonic number increases
220HZ difference between each harmonic
WIDER spacing because F0 is larger, leads to less intense/distinct sound
higher the pitch, lesser distinct
Irregularities (perturbations)
Deviations in moving object from regular path
VF vibration is not completely symmetrical or periodic
Each cycle is not completed in the exact same amount of time (aperiodic)
3 Acoustic measures of VF irregularities
- Jitter (time)
- Shimmer (amp)
- Noise to harmonic ratio (NHR)
All 3 are acoustic traits as a function of irregular VF vibrations
- Jitter (time)
Slight variations in cycle to cycle timing (aperiodic)
high jitter: HOARSE voice
- Shimmer (amp)
Slight variations in cycle to cycle amplitude
high shimmer: BREATHY voice
- Noise to harmonic ratio (NHR)
Proportion of noise to harmonic sound in voice
provides objective indicator of voice quality/roughness
High NHR: More noise, less harmonics: Very hoarse/heavy metal
Low NHR: Less noise, more harmonics: Opera singer
Rock singers don’t damage their VF because they don’t make contact
Voice quality
Subjective perceptual dimension of voice related to aeromechanical and muscular forces of VF
May sometimes indicate voice disorder, but may also just be vocal tract resonance (natural)
Independent of pitch and loudness
Voice quality 3 basic types:
- Breathiness
- Strain
- Roughness
- Breathiness
VF vibrate, but a lot of air escapes due to one or more VF paralysis
Higher shimmer(amp) irregularity
NOT a whisper since is phonated
i.e. bedroom voice
VF paralysis
Only one VF moves, or both don’t move
Not enough medial compression generated for adequate PTP, air flow escapes, shimmer, breathy
Usually left VF paralyzed because its more likely to be accidentally injured (left vagus nerve)
VF paralysis due to Iatrogenic
effect
Cranial nerve X (vagus) left branch cut on accident by a doctor during chest surgery because the left branch is much longer and deeper than right
leads to VF left paralysis
VF paralysis due to intubation
Long term intubation may cause damage to VF, intubation goes through VF and can damage VF if prolonged
- Strain
VF vibrates but “strangled” sound due to excessive effort
Spasmodic dysphonia: spasming (sudden and violent and unwilling muscle contraction) of either adductor or abductor
Spasmodic dysphonia adductor type
adductor trio spasms
Clenched tightly VF, too much medial compression, cannot adequately vibrate VF, leads to tight and strangled sound
Can whisper because adductors not in play
Spasmodic dysphonia: abductor type
Abductor muscle spasms, open glottis and breathy (Shimmer) quality
Strain and empty “glitchy”
Becomes unwantedly unvoiced
- Roughness
Colloquially Hoarseness
Strain and breathy qualities
High jitter (time): Irregular cycle to cycle timing
Examples:
Vocal nodules
Laryngitis
Laryngeal cancer
Vocal nodules
Callous-like growth on VF edges due to constant use of loud voice (could change pitch since additional mass changes resonance)
Typically:
Teachers
Children
Singers
Usually a behavioral fix, or surgically removed
Laryngitis
Inflamed VF tissue secondary to infection, can be caused by overuse, infection, irritation
Red larynx appearance
Typically goes away, temporary
Laryngeal cancer
VF and laryngeal tumor often caused by smoking
Tumor of VF sounds like laryngitis
