Vowel formant discrimination in high-fidelity speech by hearing-impaired listeners.
22
Vowel formant discrimination in high-fidelity speech by hearing-impaired listeners. Diane Kewley-Port, Chang Liu (also University at Buffalo,) T. Zachary Burkle Indiana University, SPHS Presented at the Acoustical Society of America Meeting, Austin, TX, Nov. 11, 2003.
description
Vowel formant discrimination in high-fidelity speech by hearing-impaired listeners. Diane Kewley-Port, Chang Liu (also University at Buffalo,) T. Zachary Burkle Indiana University, SPHS. Presented at the Acoustical Society of America Meeting, Austin, TX, Nov. 11, 2003. - PowerPoint PPT Presentation
Transcript of Vowel formant discrimination in high-fidelity speech by hearing-impaired listeners.
Vowel formant discrimination in high-fidelity speech by hearing-impaired
listeners.
Diane Kewley-Port,
Chang Liu (also University at Buffalo,)
T. Zachary Burkle
Indiana University, SPHS
Presented at the Acoustical Society of America Meeting, Austin, TX, Nov. 11, 2003.
Thanks to SPL Lab members
• Larry Humes (Investigator)
• Maureen Coughlin (Audiologist, ABD)
• Kelley Anderson (Research Assistant)
• Bill Mills (Programmer)
Formant Discrimination
• Just noticeable difference between standard vowel and one with shifted formant.
• Psychophysical procedures to determine thresholds formant frequency, F (Hz).
• For 10+ years, experiments have systematically varied conditions, phonetic context, F0, noise etc.
• Purpose: Examine formant thresholds for hearing-impaired listeners (HI) in nearly natural speech, including sentences
High-Fidelity Speech
• To preserve naturalness, use STRAIGHT (Kawahara et al., 1999) synthesis
• Stimulus Samples for word “bad”– Sentence– Word (standard vowel)– Word (10% F1 increment,
NH, optimal listening
Weber Fraction = 1.5%)
Formant Thresholds Hi-Fi NH
0.0
25.0
50.0
75.0
100.0
125.0
150.0
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel formant
Delta F (Hz)
ISO Hi-Fi
Word Hi-Fi
Sent Hi-Fi160%
190%
Experimental Factors for HI study
• Formant Frequency: / I E Q Ã / F1 & F2
• Audibility: 70 dB SPL partial vs. 95 dB SPL fully
• Linguistic Context: isolated vowels, words, sentences
• Sent + ID task: Sentence discrimination only vs. Sentence discrimination + ID
Hearing Impaired Listeners• 21 – 55 years old, N = 5
• Mild – moderate, high-frequency loss
Procedures
• Day 1 Screening
• Days 2-4 Training
• Days 5-23 Testing
• Linguistic Context (ISO, Word, Sent) and Sent + ID blocks randomized daily
• 95 vs. 70 dB SPL levels fixed each day
• Audibility (70 vs 95) No
• Linguistic Context Yes (ISO, Word, Sent)
• Sent + ID task No
• Explain with figures
Summary Threshold ResultsFactor Significant
• Formant Frequency (8) Yes
1) Formant
Frequency
2)Audibility
Isolated Vowels Hi-fi
0.0
50.0
100.0
150.0
200.0
250.0
300.0
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel formant
Delta F (Hz)
ISO NH 70
ISO HI 70
ISO HI 95
Sentences Hi-fi
0.0
50.0
100.0
150.0
200.0
250.0
300.0
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel formant
Delta F (Hz)
Sent 95
Sent 70
3) Linguistic Context. Thresholds different
• Why?• Post-hocs, only F word < F Sent
Linguistic Context Hi-Fi HI
0
50
100
150
200
250
300
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel formant
Delta F (Hz)
ISO
Word
Sent
Reversal, F Iso > F Word
Linguistic Context 95 dB Hi-Fi HI
0
50
100
150
200
250
300
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel formant
Delta F (Hz)
ISO
Word
Comparison HI to NH (Hi-Fi)
HI vs. NH 70 dB SPL Hi-Fi
0
50
100
150
200
250
300
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel formant
Delta F (Hz)
Word NH
Word HI
Sent NH
Sent HI
Thresholds Hi-Fi vs. Synthetic Speech
• Richie, Kewley-Port, & Coughlin (2003) reported F for isolated formant synthesized vowels (Syn) for HI
• Liu & Kewley-Port (2003) report for NH no difference Hi-Fi and Syn for isolated vowels and words
• Predict that thresholds for our Hi-Fi vowels same as Syn vowels from Richie et al.
•Hi-Fi elevated by 150%
Hi-Fi vs. Syn Isolated Vowels Soft
0.0
50.0
100.0
150.0
200.0
250.0
300.0
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel formant
Delta F (Hz)
Hi-Fi NH
Syn HI
Hi-Fi HI
Summary
• Formant discrimination by HI significantly effected by– Formant Frequency– Linguistic Context– Speech quality (Hi-Fi harder)
• Surprising Hi-Fi threshold comparisons – Thresholds for softer sentences better than
louder– hresholds for words better than isolated
vowels
Baseline Thresholds
• Normal Hearing Listeners (NH)
• Formant Synthesized (Syn)
• Female Isolated (ISO) Vowels F1 & F2
• Four Vowels: / I E Q Ã /Formant Thresholds Syn NH
0
10
20
30
40
50
60
70
80
90
100
ih1 eh1 uh1 ae1 uh2 ae2 eh2 ih2
Vowel formant
Delta F (Hz)
ISO
Linguistic Context Syn
Formant Thresholds Syn NH
0
10
20
30
40
50
60
70
80
90
100
ih1 eh1 uh1 ae1 uh2 ae2 eh2 ih2
Vowel formant
Delta F (Hz)
ISO 22 CVC
170%
Sent
250%
Added ID Task
Thresholds with or without ID Task Hi-Fi HI
0
50
100
150
200
250
300
0 500 1000 1500 2000 2500
Formant frequency (Hz)
Threshold (Hz)
95 dB, Sen. 95 dB, sen+ID70 dB, sen70 dB, sen+ID
Audibility versus Pathology
• Vowels fully audible 70 dB NH, 95 dB HI
F2 elevated by 200 %Fully Audible HI vs. NH Word Hi-Fi
0
50
100
150
200
250
300
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel formant
Delta F (Hz)
NH 70
HI 95
Listener Variability at 70 dB for Word
0.0
100.0
200.0
300.0
400.0
ih1 eh1 uh1 ae1 uh2 eh2 ae2 ih2
Vowel Fromant
Delta F (Hz)
BAC
BCC
CLM
DLN
JRM
