expatiari expatria

The young human ear responds to air pressure variations between 16 Hz and 20 kHz, which is roughly one octave below and less than three octaves above the range of an 88 key concert piano. As we age, our range decreases anywhere from these ten octaves to silence.

Shop owners have created the equivalent of a behavior altering dog whistle upon our children. Just as a dog whistle between 20 and 35 kHz is above the human range but within a dog’s audible range, a tone between 17 kHz and 20 kHz is silent to most adults but mind-numbingly annoying to children and teens. Students now use high pitch ring tones without fear of punishment for using mobile phones in class. I have a suspicion that these tones give us headaches or worse, even though we may not be conscious of the cause.

Below are 2 second sine wave samples from 27.5 Hz to 20 kHz. Caution: Some of these sounds may be very loud and incredibly annoying, if not painful. I can feel 17 kHz more than I can hear it. I can not say for sure if the last samples play correctly or at all. Also, because these tones are outside of the pleasure zone, the MP3’s are likely to be compressed, rendering them distorted or even silent.

Warning: Turn your volume way down. Seriously! These are intense sine wave.

27.5 Hz: wav mp3 (A0 lowest of 88 key piano)
55.0 Hz: wav mp3 (A1)
110.0 Hz: wav mp3 (A2)
220.0 Hz: wav mp3 (A3)
261.626 Hz: wav mp3 (C4 Middle C)
440.0 Hz: wav mp3 (A4 concert pitch)
4186.0 Hz: wav mp3 (C8 highest of 88 key piano)
10000 Hz: wav mp3 (10 kHz annoying)
11000 Hz: wav mp3 (11 kHz annoying)
12000 Hz: wav mp3 (12 kHz annoying)
13000 Hz: wav mp3 (13 kHz annoying)
14000 Hz: wav mp3 (14 kHz annoying)
15000 Hz: wav mp3 (15 kHz annoying)
16000 Hz: wav mp3 (16 kHz annoying)
17000 Hz: wav mp3 (17 kHz annoying)
18000 Hz: wav mp3 (18 kHz annoying)
19000 Hz: wav mp3 (19 kHz annoying)
20000 Hz: wav mp3 (20 kHz annoying)

10-20 kHz: wav mp3 (10 to 20 kHz increasing 1 kHz each half second, 5 seconds total)

Warning: Turn your volume way down. Seriously! These are intense sine wave.

I interpret this Equal-loudness graph to show equilvilant perceived loudness with respect to volume (y-axis) and pitch (x-axis), such that a high volume low pitch note seems to be just as loud (to a human) as a low volume mid to high pitch note.