asc sound basics 2b · 2011. 9. 17. · vasey, john (1993) concert sound and lighting systems,...

ASC SOUND BASICS 2 B

PHASE, TIMBRE LEVELS, DISTORTION

2B 2B

These are the 2 other concepts to learn about components of sound waves:

• Phase

• Timbre

These are the 2 other concepts to learn about components of sound waves:

• Phase

• Timbre

PHASE PHASE

Just as ocean waves rise to crests and fall to troughs so do sound waves.

When two identical sound waves rise and fall at the same time and place, they are in phase.

Just as ocean waves rise to crests and fall to troughs so do sound waves.

When two identical sound waves rise and fall at the same time and place, they are in phase.

When two identical sound waves rise and fall at different times they are out of phase.

When two identical sound waves rise and fall at different times they are out of phase.

• When waves arrive at a persons ears or a microphone they add together. Because of this two identical sound waves which are perfectly in phase will add together to create a new wave that is twice as loud.

• When waves arrive at a persons ears or a microphone they add together. Because of this two identical sound waves which are perfectly in phase will add together to create a new wave that is twice as loud.

• Two waves which are slightly out of phase have the effect of canceling each other out. Audibly this can make a a composite wave that sounds thin or can make the source of the wave sound like it’s shifting from side to side.

• Two waves which are slightly out of phase have the effect of canceling each other out. Audibly this can make a a composite wave that sounds thin or can make the source of the wave sound like it’s shifting from side to side.

• If two identical waves that are perfectly 180 degrees out of phase arrive at they same time they will cancel each other out and no sound will be heard.

• If two identical waves that are perfectly 180 degrees out of phase arrive at they same time they will cancel each other out and no sound will be heard.

TIMBRE TIMBRE

Most notes, from an instrument or voice, have one frequency which is the loudest – that’s known as the fundamental frequency. It’s that frequency we hear as a note’s pitch.

Most notes, from an instrument or voice, have one frequency which is the loudest – that’s known as the fundamental frequency. It’s that frequency we hear as a note’s pitch.

PRONOUNCED TAM-BUR PRONOUNCED TAM-BUR

With musical instruments, as with with almost all natural sounds, the fundamental frequency is accompanied by harmonics (overtones). These are other frequencies which can be heard (usually at a quieter level) along with the fundamental.

With musical instruments, as with with almost all natural sounds, the fundamental frequency is accompanied by harmonics (overtones). These are other frequencies which can be heard (usually at a quieter level) along with the fundamental.

These additional frequencies all add together with the fundamental to form a more complex sound and shape the sounds timbre.

These additional frequencies all add together with the fundamental to form a more complex sound and shape the sounds timbre.

When you plot a sound wave you get a waveform. The shape of the waveform dictates the type of sound you hear.

Timbre is what makes it sound different from other sounds.

When you plot a sound wave you get a waveform. The shape of the waveform dictates the type of sound you hear.

Timbre is what makes it sound different from other sounds.

The next two slides have some examples of the waveforms different instruments produce. Think of what the instrument sounds like and compare it to the waveform that it produces.

The next two slides have some examples of the waveforms different instruments produce. Think of what the instrument sounds like and compare it to the waveform that it produces.

Three of the elements of sound have a direct relationship to three elements of music:

Three of the elements of sound have a direct relationship to three elements of music:

FREQUENCY

AMPLITUDE

TIMBRE

FREQUENCY

AMPLITUDE

TIMBRE

MELODY

RHYTHM

HARMONY

MELODY

RHYTHM

HARMONY

Are there any questions about this material?

Are you absolutely sure?

BECAUSE YOU WILL SEE AND USE THIS MATERIAL AGAIN

100 % positively sure?

Let’s continue…

Are there any questions about this material?

Are you absolutely sure?

BECAUSE YOU WILL SEE AND USE THIS MATERIAL AGAIN

100 % positively sure?

Let’s continue…

Let’s summarize some of the ideas… • Sound is vibrations we are able to

hear

• Vibrations travel through space (solid, liquid, gas) in the form of waves. One complete wave motion from start to peak to trough to start is called a CYCLE. The speed at which a wave completes one cycle is its frequency.

• The number of cycles per second is expressed as a HERTZ (Hz).

• The frequency range of human hearing is 20 Hz to 20,000 Hz. This is called the AUDIO SPECTRUM.

• WAVELENGTH is another way of measuring frequency but instead of measuring number of cycles you measure the physical length of the wave.

• The greater the distance between peaks and troughs of a wave the greater the AMPLITUDE. Amplitude describes the loudness or volume of a sound.

• A wave with a greater volume than another sound wave is said to have a greater SOUND PRESSURE LEVEL or SPL.

• SPL’s are expressed in DECIBELS or dB’s. Sound Pressure is measured on a scale from 0 dB (the threshold of human hearing) to 140 dB (blown eardrums).

• When the shape of sound wave follows a regular, recurring pattern rather than a random shape we say it has PITCH.

• TIMBRE (tam – bur) is the character of a sound that makes it different from another sound. Timbre is created by the shape of the sounds waves.

A few more terms you will frequently hear and therefore you must know…

A few more terms you will frequently hear and therefore you must know…

EQUIPMENT LEVELS

DISTORTION

SIGNAL to NOISE

LEVEL METERS

FREQUENCY RESPONSE

EQUIPMENT LEVELS

DISTORTION

SIGNAL to NOISE

LEVEL METERS

FREQUENCY RESPONSE

There are 4 types of levels you will encounter. Remember that when we use the term level we mean the strength of the signal the piece of equipment puts out.

There are 4 types of levels you will encounter. Remember that when we use the term level we mean the strength of the signal the piece of equipment puts out.

EQUIPMENT LEVELS EQUIPMENT LEVELS

1. Line Level

2. Microphone Level (lower than line level)

3. Instrument level

4. Speaker level

1. Line Level

2. Microphone Level (lower than line level)

3. Instrument level

4. Speaker level

DISTORTION DISTORTION

Speaker Distortion When a speaker receives a signal that makes it perform past its physical limits.

Speaker Distortion When a speaker receives a signal that makes it perform past its physical limits.

There are several different kinds of distortion:

Electronic Distortion Signals pass through circuits. When circuits are unable to handle the level of the signal passing through them there is distortion.

Electronic Distortion Signals pass through circuits. When circuits are unable to handle the level of the signal passing through them there is distortion.

Harmonic Distortion Sometimes desirable and when used by guitar players.

Intermodulation Distortion Caused by transistors rather than tubes (which cause harmonic distortion).

The highest level a piece of equipment can handle without distorting is called its HEADROOM.

When you reach maximum headroom your signal begins to distort and this is called CLIPPING.

SIGNAL to NOISE

The signal to noise ratio is the measurement of how much signal can be heard in relation to how much signal can be heard.

SIGNAL to NOISE

The signal to noise ratio is the measurement of how much signal can be heard in relation to how much signal can be heard.

LEVEL METERS

There are traditional mechanical VU (VU – volume units) meters, bar graph LED’s and LED peak meters.

LEVEL METERS

There are traditional mechanical VU (VU – volume units) meters, bar graph LED’s and LED peak meters.

FREQUENCY RESPONSE

A measurement of a devices frequency range and how accurately it records, reproduces or transmits a given range of frequencies.

FREQUENCY RESPONSE

A measurement of a devices frequency range and how accurately it records, reproduces or transmits a given range of frequencies.

BIBLIOGRAPHY/REFRENCES/SOURCES Carter, Paul (1994) Backstage Handbook, Broadway Press Vasey, John (1993) Concert Sound and Lighting Systems, Focal Press Hurtig, Brent (1988) Multi-Track Recording, Alfred Publishing Moscal, Tony (1994) Sound Check: The Basics Of Sound and Sound Systems, Hal Leornard Corporation Cuningham, Glen (1993) Stage Lighting Revealed, Betterway Books Selden, Samuel and Sellman, Hunton D., (1964) Stage Scenery and Lighting Appleton-Century-Crofts Southern, Richard (1964) Stage-Setting for Amateurs and Professionals Theatre Arts Books Taylor, Bruce D. (1999) The Arts Equation, Back Stage Books Jewell, Don (1992) Public Assembly Facilities, Krieger Publishing Company Mountain Productions, Inc. Website: www.mountainproductions.com Peter Albrecht Company Website: www.riggingsystems.com Sapsis Rigging, Inc. Website: www.sapsis-rigging.com Boettcher, Burt J. (2000) Stage Rigging in Historic Theatres, internet article Rowoth, Alan (1997) Stage Lighting Basics, internet article Iacobucci, R. (1998) Stage Lighting Basics, internet article Columbia Encyclopedia (2000) Lighting, internet Columbia Encyclopedia (2000) Scene Design and Stage Lighting, internet

Markertek Video Supply Catalog (1999) Full Compass Catalog (1999) National Audio Video Supply Catalog (2000) Valiant Video Supply Catalog (1999) SLD Lighting Catalog (2000) Musicians Friend Catalog (2000) Bulb Direct Catalog (1999) Mackie Designs Product Brochure (2000) Mackie Designs New Product Brochure (1999) B&H Photo-Video-Audio Sourcebook (2000) Shure Brothers, Microphone and Circuitry Products Catalog (1999) Shure Brothers, Microphone Techniques: Sound Reinforcement (1997) Shure Brothers, Microphone Techniques: Studio Recording (1999)