Pitch is the perceptual characteristic that allows sounds to be classified from lowest to highest. It is directly related to the frequency of the sound wave: the higher the frequency, the higher the perceived pitch.
Discover FizziQ
How to measure it in class
With the FizziQ app, it is possible to measure the pitch of a sound using the built-in frequency meter or tuner.
Steps:
- Open FizziQ and select the “Frequency Meter” or “Tuner” instrument
- Produce a sound (voice, musical instrument, tuning fork)
- Read the frequency in Hz directly displayed on screen
- Compare different sound sources to observe the relationship between frequency and perceived pitch
- Use “Tuner” mode to identify the corresponding musical note
Scientific activities on this topic
- Study the frequencies of musical notes with a tuning fork: https://www.fizziq.org/en/activities/tuning-forks/
- Analyze vowels and their characteristic frequencies: https://www.fizziq.org/en/activities/vowels/
- Compare the pitches of different musical instruments
Learn more
The perception of pitch is one of the three main characteristics of a sound, along with intensity (loud or soft) and timbre (which distinguishes two instruments playing the same note).
Frequency-pitch relationship:
The human ear perceives sounds with frequencies between about 20 Hz (very low sounds) and 20,000 Hz (very high sounds). This range varies with age and decreases particularly for high frequencies with aging.
Musical notes:
In Western music, the note A4 is set by convention at 440 Hz. Each octave corresponds to a doubling of frequency: A5 is at 880 Hz, A3 at 220 Hz. The 12 semitones of the tempered scale are distributed according to a constant ratio of the 12th root of 2, approximately 1.0595.
Logarithmic perception:
Our perception of pitch is logarithmic: we perceive as equal intervals corresponding to the same frequency ratio, not the same difference. This is why the octave (ratio of 2) sounds the same regardless of the starting frequency.
Formula
f = v / lambda
where:
- f: sound frequency (Hz)
- v: speed of sound in the medium (approximately 340 m/s in air at 20 degrees C)
- lambda: wavelength (m)
Application examples
- The adult male voice is generally between 85 and 180 Hz, the female voice between 165 and 255 Hz
- The standard tuning fork A is at 440 Hz
- A bee’s buzzing is around 200 Hz
- A kettle’s whistle can reach 2000 Hz
- Ultrasounds (> 20 kHz) are inaudible but detectable with certain sensors
FAQ
Q: Why do two instruments playing the same note sound different? A: They have the same fundamental frequency (same pitch) but different harmonics, giving a distinct timbre. FizziQ’s frequency meter detects the fundamental frequency.
Q: Can you see the frequencies of a sound? A: Yes, with FizziQ’s spectrogram which displays the frequencies present in a sound over time. This is particularly useful for analyzing voice or instruments.
Q: Why isn’t A always at 440 Hz? A: The convention of A at 440 Hz (tuning fork) was only established in the 20th century. Baroque orchestras often use 415 Hz, and some modern orchestras go up to 442-444 Hz.
Q: How does the smartphone measure frequency? A: The microphone captures the sound signal, which is then analyzed by a fast Fourier transform (FFT) to identify the frequencies present.
Related concepts
Frequency - Period - Octave - Tempered scale - Timbre - Sound spectrum - Fourier transform