Frequency is measured in hertz, meaning cycles per second. A pure tone at 400 hertz repeats twice as often as one at 200 hertz. Their perceived pitches differ, although pitch also depends on the sound's structure and the listener. In this controlled comparison, amplitude stays fixed so the change in repetition is clear.
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What makes one note higher than another?
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frequency
The number of complete cycles per second.
pitch
How high or low a sound is perceived.
Watch · Try · Explain
See how it works
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Pure-tone frequency comparison over 20 milliseconds; motion is slowed and no audio is produced.
What to look for
- Both graphs use the same time window
- Higher frequency fits more cycles
- Amplitude is held fixed
Explain what you noticed
Tone A makes 300 cycles each second and tone B makes 600. Which simple tone usually has the higher pitch?
Keep this idea: Compare cycle counts over the same time, not wave heights.
Follow the sources
- NIH Curriculum Supplement — Hearing, Communication, and Understanding
- NIH / NIDCD — How Is Sound Measured?
- OpenStax, Rice University — Speed of Sound, Frequency, and Wavelength
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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