What is audio frequency? (2025 Update)
Educational and Fun Activities
Written by Alexandra Stone
05 April 2024
🕓 5 min
What is Audio Frequency?
Sound is something we experience every day, but have you ever wondered why some sounds are deep and others are high-pitched? The answer lies in audio frequency, which determines how we perceive different sounds.
At The Science of Sound, we love turning complex sound concepts into engaging, hands-on learning experiences. Through our STEM workshops, after-school clubs, and holiday camps, children explore how audio frequency affects music, speech, and everyday noises.
In this blog, we’ll uncover what audio frequency is, how it influences sound, and fun experiments to explore frequency at home!
1. The Basics of Audio Frequency
Audio frequency refers to the number of vibrations per second in a sound wave, measured in Hertz (Hz). The more vibrations per second, the higher the frequency, and the higher the pitch we hear. The fewer vibrations, the lower the frequency, resulting in a deeper sound.
Key Facts About Frequency:
✔ Low Frequency = Deep Sounds – A bass drum or a growling animal has a low frequency (e.g., 50 Hz).
✔ High Frequency = High-Pitched Sounds – A whistle or a bird chirping has a high frequency (e.g., 15,000 Hz).
✔ Human Hearing Range – The average person can hear sounds between 20 Hz and 20,000 Hz, though this range decreases with age.
Fun Fact:
Dogs can hear frequencies up to 45,000 Hz, while bats can detect frequencies above 100,000 Hz, helping them navigate in the dark using echolocation!
Understanding frequency helps us appreciate how sound is produced, processed, and experienced differently across various environments.
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
Audio frequency determines how we perceive different sounds, shaping the way we experience speech, music, and the world around us. Our brains interpret sound frequencies as different pitches, which is why we can tell the difference between a deep drumbeat and a high-pitched whistle.
How Frequency Changes Our Hearing Experience:
✔ Musical Instruments – A flute plays at high frequencies, while a double bass produces low-frequency sounds. The variation in pitch helps create melodies and harmonies.
✔ Speech Recognition – Human voices contain multiple frequencies. Low frequencies help us detect deep voices, while high frequencies make speech clearer and more distinct.
✔ Animal Sounds – Different animals communicate using specific frequencies. Elephants use low-frequency infrasound to talk over long distances, while birds rely on high-frequency chirps to communicate quickly.
✔ Everyday Noises – A car engine hums at a lower frequency, while a phone ringtone has a higher frequency, helping us recognize different sounds instantly.
Fun Fact:
Some people have perfect pitch, meaning they can identify a specific sound frequency just by hearing it—this rare ability is most commonly found in musicians!
Understanding how frequency shapes what we hear helps us appreciate the complexity of sound perception and how we interact with our sonic environment.
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:
Exploring audio frequency at home can be fun and easy with simple experiments that help children visualize and hear frequency changes in action.
Experiment 1: Elastic Band Guitar
What You'll Need:
✔ An empty tissue box or a shoebox
✔ Rubber bands of different thicknesses
✔ Scissors (optional, to adjust rubber band length)
Steps:
- Stretch different-sized rubber bands around the opening of the box.
- Pluck each rubber band and listen to the pitch changes.
- Observe how thicker, looser bands create lower-frequency sounds, while thinner, tighter bands produce higher-frequency sounds.
What’s Happening?
Rubber bands vibrate at different frequencies depending on their thickness and tension. This is similar to how string instruments like guitars and violins produce different pitches.
Experiment 2: Tuning Fork and Water
What You'll Need:
✔ A metal tuning fork
✔ A bowl of water
✔ A hard surface to strike the tuning fork
Steps:
- Strike the tuning fork against a hard surface to make it vibrate.
- Place the tip of the vibrating tuning fork into the bowl of water.
- Watch as ripples appear in the water, demonstrating the frequency of the sound waves.
What’s Happening?
The tuning fork vibrates at a specific frequency, transferring energy into the water and creating visible waves—just like sound waves travel through the air!
4. Fun Experiments with Audio Frequency
Audio frequency is a key factor in how we experience and interact with the world. From recognizing voices to detecting danger signals, different frequencies shape our perception of sound and play a crucial role in communication, technology, and music.
Everyday Uses of Audio Frequency:
✔ Recognizing Voices – Each person’s voice has a unique frequency range, helping us identify and distinguish between different speakers.
✔ Music & Instruments – Musical notes are based on specific frequencies, which is why different instruments produce distinct sounds.
✔ Alarms & Alerts – High-pitched frequencies are used in fire alarms, sirens, and ringtones to grab attention quickly.
✔ Medical Applications – Ultrasound machines use high-frequency sound waves to create images of organs and monitor babies during pregnancy.
✔ Communication Technology – Telephones, radios, and Wi-Fi all rely on different frequency bands to transmit sound and data effectively.
Fun Fact:
Some animals rely on low-frequency infrasound for communication—elephants can “talk” to each other from miles away using deep rumbles that humans can’t hear!
Understanding audio frequency helps us appreciate how sound works and why certain sounds travel farther, grab our attention, or impact technology in fascinating ways.
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. How Audio Frequency is Used in Technology?
Audio frequency is not just about what we hear—it plays a crucial role in technology and innovation, shaping the way we communicate, detect, and interact with sound.
Real-World Applications of Audio Frequency:
✔ Radio & Wireless Communication – Different frequency bands allow us to send and receive radio, TV, and mobile phone signals.
✔ Ultrasound in Medicine – High-frequency sound waves create detailed images of internal organs and monitor baby development during pregnancy.
✔ Sonar & Echolocation – Ships and submarines use low-frequency sound waves to detect objects underwater, just like dolphins and bats do.
✔ Noise-Cancelling Headphones – These work by detecting incoming sound waves and generating an opposite wave to cancel noise.
✔ Smart Assistants & Voice Recognition – Devices like Alexa and Siri use frequency analysis to understand and process human speech.
Fun Fact:
Whales use low-frequency sounds to communicate across hundreds of miles underwater, making them some of the loudest and most far-reaching communicators in nature!
From medical advancements to wireless communication, audio frequency is at the heart of many of the technologies we use every day.
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 part of how we experience the world. Whether it’s the low rumble of thunder, the high-pitched chirp of a bird, or the unique tone of a loved one’s voice, frequency helps us navigate sound in everyday life, music, and technology.
By understanding how frequency works, we gain insight into how sound waves behave, how different frequencies affect what we hear, and why audio plays such an essential role in communication and science. From musical instruments to medical imaging, frequency is everywhere!
At The Science of Sound, we bring sound science to life through hands-on STEM workshops, after-school clubs, and holiday camps. Our programs help children explore sound waves, frequency, and acoustics in a fun and interactive way.
