What is sound?
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Simple Definition: Interruptions in the flow of air
Sound is a type of energy made by vibrations. When any object vibrates, it causes movement in the air particles. These particles bump into the particles close to them, which makes them vibrate too, causing them to bump into more air particles. This movement, called sound waves, keeps going until they run out of energy. If your ear is within range of the vibrations, you hear the sound. -www.sciencekidsathome.com |
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Sound waves travel away from the source of interruption like wave ripples in the water
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what is pitch? |
Simple Definition: The amount of airflow interruptions that happen each second
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We consider a note to have a low pitch if the air flow is interrupted less frequently each second
We consider a note to have a high pitch if the air flow is interrupted more frequently each second
This is where we get the term frequency to describe pitch. Pitch is determined by how often or how frequent the air molecules are displaced and then come back to their original position.
We consider a note to have a high pitch if the air flow is interrupted more frequently each second
This is where we get the term frequency to describe pitch. Pitch is determined by how often or how frequent the air molecules are displaced and then come back to their original position.
HZ |
Frequency is measured in Hertz or Hz
Hz = the number of cycles per second A cycle is how long it takes the air to come back to its original spot before it was interrupted |
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When you sing/play the note
A4 the air vibrates 440 times per second A4 is therfore 440Hz |
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When you sing/play the
note C6 the air vibrates 1,046 times per second C6 is therefore 1,046 Hz |
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In nature we associate small things with high pitches
and large things with low pitches. It is easier for small things to vibrate faster than large things, which creates a higher frequency sound wave. |
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How do we create sound with our voices?
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The vocal folds sit at the top of the airway. During exhalation the vocal folds come together and vibrate, interrupting the air flow. However many times the folds vibrate per second is the pitch being sung.
Example: If the vocal folds vibrate 500 times per second, the airflow is being interrupted 500 times per second and the pitch is 500 Hz. |
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Parts of the vocal folds can vibrate up to 3,000 times per second and even faster! How is this possible? This video shows how versatile vocal fold tissue can be, even though the vibrations go much faster than the camera can capture. Check out the Vocal Folds page to learn more.
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REQUIREMENTS FOR MOST SOUNDSPOWER SOURCE
Something that inspires the start of vibration |
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example for speaking/singingRIBS, DIAPHRAGM, ABDOMINALS
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OSCILLATOR
Something that vibrates |
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VOCAL FOLDS
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RESONATOR
A cavity of air that vibrates in sympathy with parts of the original sound and makes them louder |
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VOCAL TRACT
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TRANSMITTER
Something the sound wave travels through a material that can be compressed either air, liquid or solid |
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AIR (most often for speaking/singing)
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RECEIVER
Something that interprets the sound |
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EARS and BRAIN
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harmonics
We've said that the number of times the vocal folds vibrate per second is the pitch that is produced. But this isn't quite the whole story. The vocal folds actually vibrate at multiple different frequencies at once. The vibrations that are faster than the original vibration are called harmonics or overtones.
simple definitions |
Harmonics - vibrations that are faster than the original vibration and occur simultaneously with the original vibration.
Fundamental pitch - the original and lowest vibration. Also the strongest vibration unless altered by a resonator. This frequency is what we name the pitch we are singing. |
All sounds in nature have harmonics
That is to say all things in nature, including the vocal folds, vibrate at multiple frequencies at once
That is to say all things in nature, including the vocal folds, vibrate at multiple frequencies at once
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The only way to produce one singular sound wave without harmonics (called a sine wave) is with a tuning fork or electronic synthesizer
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Go to the Harmonics vs. Formants page for further explanation on harmonics
reading sound graphs
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This is not what sound waves look like traveling through space. This is a graph of a sound wave. Sound waves do not travel in a straight line. They radiate in all directions at once.
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The graph of a sound wave is meant to show you how the air molecules are being displaced.
The x-axis represents the original position of the air molecule before it was interrupted by the wave.
The arc above the line shows how many air molecules are brought together at a certain point in time.
The arc below the line shows how many air molecules are pushed apart at a certain point in time.
The x-axis represents the original position of the air molecule before it was interrupted by the wave.
The arc above the line shows how many air molecules are brought together at a certain point in time.
The arc below the line shows how many air molecules are pushed apart at a certain point in time.
Louder pitch
(or higher amplitude)
More air molecules are being brought together and pushed apart during each cycle
Higher pitch
Air molecules are being brought together and pushed apart more frequently each second
(or higher amplitude)
More air molecules are being brought together and pushed apart during each cycle
Higher pitch
Air molecules are being brought together and pushed apart more frequently each second
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A low pitch may have to travel all the way around the room before it completes one cycle and reaches the ear. This is why bass notes can often be heard from long distances away.
A high pitch will have gone through many cycles before it reaches the ear. This is one reason high notes often sound 'clearer' to listeners. If a pitch is lower than 20 Hz, it is considered inaudible and referred to infrasonic. If a pitch is higher than 20,000 Hz, it is considered inaudible and referred to ultrasonic. If low notes have a slow enough frequency, they will sound like individual pulses. Example in vocalization: vocal fry. If high notes have a high enough frequency, they will be physically painful to the ear, hitting the ear drum at 1,000s of times each second. |
The issue with "projecting" your voice
The air molecules that originate a sound wave don't actually travel or cover any distance as the sound waves spread. It is the energy between the air molecules that creates the sound wave. |
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Reading Voice Analyzer SoftwareCheck out our Software & Equipment page for a list of voice analyzing software options
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If you sing into the analyzer it will show you many different sound wave graphs at once.
The lowest line (and often the loudest or darkest colored) is the fundamental pitch. This is the name of the pitch you are singing. The lines above it are all the harmonics present in the voice. All of these sound waves exist at once in one sound. The vocal folds are vibrating at all of these frequencies at once and your ear is interpreting all of these frequencies at once as one sound. |
sound vs. noise
Sound waves are periodic - they repeat themselves. The same amount of air that is pushed apart comes right back together and then the cycle repeats.
Noise waves is aperiodic - the wave does not show a pattern.
Noise waves is aperiodic - the wave does not show a pattern.
In speech and singing, consonants are often noise waves and vowels are sound waves.
sound waves vs. light waves
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The information on this page can be found in many other source documents that explore it in more detail. If you'd like to know more about this topic, we encourage you to read Fascinations of the Human Voice by Ingo Titze, Principles of Voice Production by Ingo Titze, or Your Voice: An Inside View by Scott McCoy.
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If you see something that is yours that you feel is being used without proper permission, please let us know and we will gladly credit you or remove it. Thanks for your help!
If you see something that is yours that you feel is being used without proper permission, please let us know and we will gladly credit you or remove it. Thanks for your help!
