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Hearing: Loudness
Measuring loudness
• Loudness matching • Start with one frequency at a given
intensity level • 1000Hz tone at 20dB
• How loud do other frequencies need to be so that they sound as loud? • adjust 100Hz tone so it sounds as
loud as the 1000Hz 20dB tone
Equal Loudness Contours Measuring loudness
• Magnitude estimation • Assign sounds numeric values
depending on how loud they sound
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Measuring loudness
Trial dB Approx value
Trial dB Approx value
1 +15 500 11 -‐10 30
2 -‐5 50 12 +15 500
3 -‐20 10 13 +20 1000
4 0 100 14 -‐5 50
5 -‐10 30 15 +10 300
6 +20 1000 16 -‐15 20
7 +5 200 17 -‐5 50
8 +10 300 18 -‐20 10
9 -‐15 20 19 +5 200
10 0 100 20 +15 500
Measuring loudness
• Magnitude estimation
Temporal integration
• Adding up sound energy over time • 100 msec sounds louder than 10 msec
Loudness coding
• We can perceive a range of 130dB • But AN fibers respond over a much smaller
range
Loudness coding
• Can we rely on different cells with different ranges?
Loudness coding • Look at pattern across cells with different
CFs.
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