What is audio frequency?

Educational and Fun Activities


Written by Alexandra Stone

05 April 2024

đź•“ 5 min

Sound is something we experience every day, but do we really understand what makes each sound different? One key aspect is audio frequency. Frequency plays a crucial role in how we perceive sounds—whether they're high-pitched like a bird's chirp or low like the rumble of thunder. But what exactly is audio frequency, and how does it work?

1. The Basics of Audio Frequency


Audio frequency refers to the number of times a sound wave vibrates per second, measured in Hertz (Hz). The higher the frequency, the higher the pitch of the sound. The lower the frequency, the deeper or lower the pitch. Humans can typically hear sounds with frequencies between 20 Hz (low-pitched) and 20,000 Hz (high-pitched), though this range can vary with age and health.

For example:

  • A sound with a frequency of 50 Hz might be a low rumble, like distant thunder.
  • A sound with a frequency of 1,000 Hz would be closer to the pitch of a human voice.
  • A frequency of 15,000 Hz could be similar to the high-pitched sound of a dog whistle, which some adults may not even hear.

Explore the fascinating world of high-frequency sounds in our blog post What are Ultrasonics? to understand how frequencies beyond our hearing are used in technology and nature.

2. How Frequency Affects What We Hear


Our brains interpret different frequencies as different pitches. Musical instruments are a great way to experience this. For instance, a flute produces high-frequency sounds, while a double bass creates low-frequency sounds. The same principle applies to everyday noises. That’s why a car engine’s hum sounds deeper than a bird’s song.

Want to dive deeper into the science of sound? Read more in The Anatomy of the Ear, where we explore how the ear processes different frequencies and turns them into sounds we can understand.

3. Relationship to Pitch:


Pitch is closely related to audio frequency, with higher frequencies corresponding to higher pitches and lower frequencies to lower pitches. For example, a bass drum produces low-frequency sounds with a deep, booming quality, while a flute generates high-frequency sounds with a crisp, airy timbre. The pitch perception of the human ear is logarithmic, meaning that doubling the frequency results in an increase of one octave in pitch.

4. Fun Experiments with Audio Frequency


You can easily explore frequency at home with a few simple materials:

  • Elastic band guitar: Stretch an elastic band over an empty box. Pluck the band and notice the sound it makes. Now, stretch it tighter and pluck again—do you hear how the pitch changes? The tighter the band (higher frequency), the higher the pitch.
  • Tuning fork exploration: Strike a tuning fork and listen to the pitch it makes. Different tuning forks vibrate at different frequencies, so try out several to compare the sounds they produce.

For more ways to engage children with sound, check out our blog Crafting Musical Instruments with Everyday Materials, where we show how to turn everyday objects into musical creations.

5. Why is Audio Frequency Important?


Audio frequency isn’t just important for musicians or sound engineers; it’s essential for how we communicate and interact with the world. It helps us recognise voices, enjoy music, and even detect danger (like the high-pitched screech of a fire alarm). Understanding frequency can also protect your hearing—high-frequency sounds, especially at high volumes, can damage your ears over time.

Find out more about how sound affects us in The Role of Sound in Industry and Technology, where we explore how different frequencies are used in various sectors to enhance communication and safety.

Final Thoughts

Audio frequency is a fundamental aspect of how we experience the world around us. By understanding it, children can learn how different pitches and sounds are created, helping to foster a deeper appreciation for music, nature, and science.

If your child enjoys learning about sound, why not introduce them to our Science of Sound holiday camps? These hands-on sessions offer fun experiments and activities that make science and sound come to life. Learn more about our upcoming camps here.

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The Science of Sound