Loudness and Pitch

1
Loudness and Pitch
2
Loudness

• Subjective correlate of intensity
• Normally use terms such as soft, comfortable,
  loud, softer, or louder, etc.

3
Scales

• Sone Scale
• Phon Scale

4
Sone scale

• Used to measure the growth of loudness.
• Based on a 40 dB SL, 1000 Hz reference
• When a sound is twice as loud it is two sones,
  when it is four times louder than the reference
  it is four sones, etc.
• In normal hearing people two sones is equal to
  about a 10 dB increase (50 dB SL). Every
  doubling of loudness yields an additional 10 dB
  SL in intensity increase.

5
Example of Sone Scale
6
Phon Scale

• Based on concept of equal loudness contours
• Used to measure loudness across frequencies.

7
Example of Phon Scale
8
Pitch

• Subjective correlate of frequency
• Normally use terms such as low pitch, high pitch,
  lower and higher pitch, etc.

9
Mel Scale

• 40 dB SL 1000 Hz as a reference.
• 1000 mels 1000 Hz
• Subjects are required to match increases in
  frequency with increases in pitch.
• Research has shown that frequency rises at a
  higher rate than pitch.
• What are the implications?

10
Growth of pitch
11
Summary