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Transcript of Effect of reverberation on loudness perceptionInsert footer on Slide Master© University of Reading...
Effect of reverberation on loudness perceptionInsert footer on Slide Master © University of Reading 2010 www.reading.ac.uk
Department of Psychology
18 April 2023
Effects of reverberation on loudness perceptionAndrew Raimond
Effect of reverberation on loudness perception 2
Overview
• Previous Experiments– Pilot; Real-room reverberation; Mono v Dichotic.
• Current Experiments– Time order effects– Effects of frequency bands
Effect of reverberation on loudness perception
Loudness asymmetry
3
Time
Am
plitu
de
Damped Sound
Ramped Sound
Damped
RampedAttack
Decay
Atta
ck
Decay
Effect of reverberation on loudness perception
Loudness context effect
4
• Which is loudest?
Time
Ramped Ramped
Damped Damped
Damped Ramped
Ramped Damped
Effect of reverberation on loudness perception
Reverberation
• The “tails” on damped stimuli resemble effects of room reflections (Stecker & Hafter, 2000; Watkins, 2005).
5
Dry speech
Reverberated speech
Dry Speech
Reverberant Speech
Effect of reverberation on loudness perception
Questions
• Perceived reduction in loudness of damped stimuli relative to ramped stimuli– is this still apparent with sounds that have tails processed from real-
room reflections?
• The loudness context effect– is this still apparent with sounds that have tails processed from real-
room reflections?
7
Effect of reverberation on loudness perception
Real-room reverberation
• However, tails added by real-room reverberation differ from the envelopes used by Stecker & Hafter:
- Real-room decays are not smooth
- Durations of real-room decays are usually longer
- Room-reflections de-correlate the signal at the two ears
8
Left Channel
Right Channel
Effect of reverberation on loudness perception
Experiment 1: Real-room
• Can real-room reverberation over-ride artificial shaping used by Stecker & Hafter?
• Perceived reduction in loudness of damped stimuli relative to ramped stimuli?
• The loudness context effect?
– Loudness asymmetry– Loudness context effect– Convolution with real-room reverberation overrides shaping used by
Stecker & Hafter.– Effects of real-room reflections are more substantial than shaping used by
Stecker & Hafter
9
Effect of reverberation on loudness perception
Experiment 2: Monaural v Dichotic
• Certain room-reflection ‘tail effects’ that have been found in speech perception experiments are increased in monaural conditions (Watkins, 2005).
• Is the loudness context effect also increased when sounds are presented in monaural real-room reverberation?
– Loudness asymmetry– Loudness context effect
– Effects of the real-room tails successfully oppose effects of the function-shaped tails, as there was a substantial context effect that depended on the direction of the real-room tail.
– As with ‘tail effects’ in speech, this context effect is found in both monaural and dichotic conditions, but is less prominent in dichotic conditions .
– There appears to be a ‘de-reverberation’ in dichotic conditions that may be due to the de-correlation between the two ears’ signals with the real-room BRIRs
10
Effect of reverberation on loudness perception 11
Damped-Ramped
Ramped-Damped
Ramped-Ramped
Damped-Damped
1700 ms
1350 ms
1350 ms
1000 ms
(Loudest)
(Least loud)
Experiment 3: Time order effects
Time
500 ms ISI
Effect of reverberation on loudness perception 12
Experiment 3: Time order effects
Ramped- Ramped
850 ms
Damped- Damped
850 ms
Peak-to-Peak 1700 ms
Damped- Ramped
500 ms
Ramped- Damped
1200 ms
850 ms
Effect of reverberation on loudness perception
• 2IC task.
• Pure tones of equal power (330 Hz, 250 ms).
• Gated with either Ramped or Damped envelope, convolved with real-room 2.5 m BRIRs.
• Played through left channel.
• Standard stimulus (80 dB SPL), then ISI of 500,850,1200 or 1550 ms
• Then Test stimulus (selected at random from 70,72,.., 90 dB SPL)
• Which is loudest?
13
Experiment 3: Time order effects
Effect of reverberation on loudness perception
Damped Test
Experiment 3: Results
14
500 ms ISI
70 82 907874 86 70 82 907874 86
1
0
.5
Pro
port
ion
Tes
t > S
tand
ard
resp
onse
s
Test level (dB SPL)
Ramped Standard Damped Standard
Ramped Test
P.S.E
P.S.E
Effect of reverberation on loudness perception
Damped Test
Ramped Test
Experiment 3: Results
15
850 ms ISI
70 82 907874 86 70 82 907874 86
1
0
.5
Pro
port
ion
Tes
t > S
tand
ard
resp
onse
s
Test level (dB SPL)
Ramped Standard Damped Standard
P.S.E
P.S.E
Effect of reverberation on loudness perception
Damped Test
Ramped Test
Experiment 3: Results
16
1200 ms ISI
70 82 907874 86 70 82 907874 86
1
0
.5
Pro
port
ion
Tes
t > S
tand
ard
resp
onse
s
Test level (dB SPL)
Ramped Standard Damped Standard
P.S.E
P.S.E
Effect of reverberation on loudness perception
Damped Test
Ramped Test
Experiment 3: Results
17
1550 ms ISI
70 82 907874 86 70 82 907874 86
1
0
.5
Pro
port
ion
Tes
t > S
tand
ard
resp
onse
s
Test level (dB SPL)
Ramped Standard Damped Standard
P.S.E
P.S.E
Effect of reverberation on loudness perception
Experiment 3: Pooled Results
18
Ramped Damped
850 ms ISI500 ms ISI
Tot
al P
ropo
rtio
n T
est >
Sta
ndar
d R
espo
nses
Ramped Test
Damped Test
Standard Type
Ramped Damped
0.5
0.7
0.3
0.9
0.5
0.7
0.3
0.9
Effect of reverberation on loudness perception
Experiment 3: Pooled Results
19
Ramped Damped
1550 ms ISI1200 ms ISI
Tot
al P
ropo
rtio
n T
est >
Sta
ndar
d R
espo
nses
Ramped Test
Damped Test
Standard Type
Ramped Damped
0.5
0.7
0.3
0.9
0.5
0.7
0.3
0.9
Effect of reverberation on loudness perception
70 82 907874 86
1
0
.5
Pro
port
ion
Tes
t > S
tand
ard
resp
onse
s
Damp test 850 ms ISI
Ramp test 500 ms ISI
Experiment 3: Results
20
Equal Peak-to-Peak Times
Test level (dB SPL)
P.S.E
Damp test 1200ms ISI
Ramp test 850ms ISI
70 82 907874 86
Damped StandardRamped Standard
P.S.E
Effect of reverberation on loudness perception
Experiment 3: Conclusions
21
• Loudness asymmetry and loudness context effect are not dependant on Peak-to-Peak distance.
• While still able to make loudness judgments, loudness asymmetry disappears with ISIs longer than 850 ms.Thus, loudness context effect does so too.
• However, standard only contains one 300 ms reverberant tail, in one frequency region. Wideband (speech) contexts contain many more reverberant tails.
Effect of reverberation on loudness perception
Experiment 4:
22
• Ongoing experiments: Effects of frequency bands
Effect of reverberation on loudness perception
Experiment 4: Effects of frequency bands
23
• Perceptual constancy for reverberation is more effective within wideband sounds (Watkins & Makin, 2007).
• Perceptual mechanism seems to operate on a band-by-band basis.
• Test and standards used in Stecker & Hafter and in previous experiments have all occupied the same narrowband frequency region (300-Hz).
• Use standards and test sounds in different frequency bands to examine loudness asymmetry
• Investigate if loudness context effects are still apparent with cross-band standards and test sounds.