- Explain the fundamentals of frequency and pitch in the context of sound and music
- Assess musical elements including notes, half-steps, whole steps, and octaves
- Determine octave frequencies and their relevance in music
Imagine a world without music and many of us would struggle to fill the void. Music uplifts, inspires, heals, and generally adds dimension to virtually every aspect of our lives. But what is music? For some it is a song; for others it may be the sounds of birds or the rhythmic sound of drumming or a myriad of other sounds. Whatever you consider music, it is all around us and is an integral part of our lives.
“The world’s most famous and popular language is music.”
Psy, South Korean singer, rapper, songwriter, and record producer
Basics of Frequency as It Relates to Sound
Every sound is created by an object vibrating and these vibrations travel in waves that are captured by our ears. Some vibrations we may be able to see, such as a plucked guitar string moving, whereas other vibrations we may not be able to see, such as the sound created when we hold our breath when accidentally dropping our phone on a hard floor. We don’t see the vibrations of our phone hitting the floor; however, any audible sound created in the fall is the result of vibrations in the form of sound waves, which can be pictured similarly to waves moving through the ocean.
The waves of sounds each have a frequency, or rate of vibration of sound waves, that measures the number of waves completed in a single second and are measured in Hertz(Hz; one Hz is one cycle per second). Louder sounds have stronger vibrations or are created closer to our ear. The further an ear is from the source of the sound, the quieter the sound will appear.
frequency
Frequency in sound refers to the number of vibrations per second of a sound wave, measured in Hertz (Hz), and it determines the pitch of the sound we hear.
Higher frequencies result in higher-pitched sounds, while lower frequencies produce lower-pitched sounds.
Sounds range in frequency from [latex]16[/latex] Hz to ultrasonic values, with humans able to hear sounds in a frequency range of about [latex]20[/latex] Hz to [latex]20,000[/latex] Hz. Adults lose the ability to hear the upper end of the range and typically top out in the ability to hear in a frequency of [latex]15,000–17,000[/latex] Hz. Sounds with a frequency above [latex]17,000[/latex] Hz are less likely to be heard by adults while still being audible to children.
While frequency plays a key role in audible sounds, so too does the sound level, which can be measured in decibels (dB), which are the units of measure for the intensity of a sound or the degree of loudness. As a sound level increases, the decibel level increases.
decibels
Decibels (dB) measure the intensity or loudness of a sound, with higher decibel levels indicating louder sounds and lower levels indicating softer sounds.
A person with average hearing can hear sounds down to [latex]0[/latex] dB. Those with exceptionally good hearing can hear even quieter sounds, down to approximately [latex]–5[/latex] dB. The following table includes sample sounds with their related decibel values.
| Sound | Decibels (dB) |
|---|---|
| Firecrackers | [latex]140[/latex] |
| Take-off of military jet from aircraft carrier | [latex]130[/latex] |
| Clap of thunder | [latex]120[/latex] |
| Auto horn standing next to the vehicle | [latex]110[/latex] |
| Outboard motor | [latex]100[/latex] |
| Motorcycle | [latex]90[/latex] |
| Noise inside a car in city traffic | [latex]80[/latex] |
| Typical washing machine | [latex]70[/latex] |
| Public conversation, such as at a restaurant | [latex]60[/latex] |
| Private conversation | [latex]50[/latex] |
| Hum of a computer with fan blowing | [latex]40[/latex] |
| Quiet whisper | [latex]30[/latex] |
| Swishing leaves | [latex]20[/latex] |
| Regular breathing | [latex]10[/latex] |
| Lowest typical sound audible by teenagers | [latex]0[/latex] |
Select the most representative decibel value for each of the following sounds:
- car wash: [latex]25[/latex] dB, [latex]55[/latex] dB, [latex]85[/latex] dB
- vacuum cleaner: [latex]15[/latex] dB, [latex]70[/latex] dB, [latex]90[/latex] dB
- ship’s engine room: [latex]30[/latex] dB, [latex]65[/latex] dB, [latex]95[/latex] dB
- approaching subway car: [latex]70[/latex] dB, [latex]100[/latex] dB, [latex]120[/latex] dB
Basics of Pitch
When considering the various sound levels the human ear can hear, the ear perceives sound both from the frequency level and the pitch of a sound. The quality of the sound is referred to as pitch, the tonal quality of a sound and how high or low the tone. Sounds with a high frequency have a high pitch, such as [latex]900[/latex] Hz, and sounds with a low pitch have a low frequency, such as [latex]50[/latex] Hz.
pitch
Pitch is the tonal quality of a sound that allows us to perceive it as high or low, and it is directly related to the frequency of the sound wave.
Understanding pitch helps us differentiate between various sounds in our environment, from musical notes to spoken language.
Let’s take a look at frequency and pitch using a string instrument such as a guitar or piano. When a string is plucked on a guitar or a key is played on a piano, the related string vibrates at a frequency that is related to the length and thickness of the string. The frequency is measurable and has a singular value. The pitch of the note played is open for interpretation, as the pitch is a function of personal opinion.
It may be interesting to note that a TI-84 and TI-Nspire graphing calculators can be utilized to tune a musical instrument by measuring the frequency of a note using a small plug-in accessory that captures the sound waves from a note and displays the corresponding frequency. Using the displayed frequency, an instrumentalist can then make the needed adjustments to perfectly tune an instrument. This method of tuning an instrument can be helpful whether a novice player or a seasoned instrumentalist because the instrument can be tuned precisely to the correct frequency.