dB SPL Sound Source (with distance) - Brian K. Shepard

Sound and Acoustics 

MUEA 474a • Electronic Synthesizer Techniques

What does sound look like? 

MUEA 474a – 02 Sound and Acoustics

What does sound look like? 


Sound Wave Propagation 

Compression Normal Pressure Rarefaction 

Movement of Air Molecules Away from Vibrating Source 


Speed of Sound 

� 343 meters per second (1125 fps) in air 

� Sea level 

� Dry air 

� 20ºC (68ºF) 

� Warmer – Faster 

� Cooler – Slower 

� In water travels 4.3 times faster than 

same temperature air 

� Does not travel in a vacuum 

(outer space) 


Sound Wave Period 

MUEA 474a – 02 Sound and Acoustics 

Wave Period 

� The Wave Period represents one complete cycle of a 

wave going through both its positive and negative energy 

phases, and returning to the original starting energy level

Sound Wave Frequency 

1 second 

� The waves at the bottom of the drawing above are 

completing more periods per second, and thus, have a 

higher frequency, than the waves at the top of the drawing 

� Note that they all have the same Amplitude 

� With sound, we usually relate Frequency to Pitch 

� The higher the Frequency, the higher the perceived Pitch 


Sound Wave Frequency 

� With energy waves, Frequency represents the number 

of completed Wave Periods in one second 

� If a sound wave completes a period in 1/100 th of a second, 

then it will complete 100 periods in one second 

� In audio, we use the term Hertz (Hz) to indicate cyclesper-second 

� (Note: upper-case H, lower-case z) 

� For 1000s, we use the prefix kilo (kHz), 10,000Hz = 10kHz 

� Thus, if a wave completes 100 periods per second, we say 

that the Frequency of the wave is 100Hz 


Sound Wave Amplitude 


Amplitude 

� The magnitude of change in an oscillating wave. 

� With sound waves, Amplitude refers to the intensity, or 

magnitude, of air pressure change from the ambient air 

pressure

Sound Wave Amplitude 

� With sound, we most commonly associate Amplitude 

with Loudness 


High Amplitude 

Low Amplitude

Hearing, Perception & Psychoacoustics 

� Audio Equipment and Human Hearing are not equal 

� Audio Equipment tends to be linear and literal 

� Human Hearing is non-linear and subjective 


≠

The Ear 


The Outer Ear 

� Flesh and cartilage structure called the Pinna 

� Not the Earlobe 

� Earlobe is the little fleshy part at the bottom of the Pinna that 

you put your earring in 

� Pinna focuses sound energy into 

the ear canal 

� Ridge structures on Pinna help 

with sound localization 


The Middle Ear 

� Ear drum (tympanic membrane) moves back and forth 

with changes in SPL 

� Hammer, Anvil, and Stirrup act as volume control while 

passing SPL to inner ear 


The Inner Ear 

� Cochlea has spiral, fluid-filled 

chamber with tiny, hair-like 

receptors that respond to 

different frequencies 


The Inner Ear 

� High frequency receptors are triggered first 


Hearing Frequencies 

Pitch Timbre or “Color” Presence or “Space” 


CD and DVD Audio (20Hz-20kHz) 

Telephone (200Hz-4kHz) 

Orchestral Strings (30Hz-16kHz) 

Trumpet (160Hz-8kHz) 

Speech (80Hz-12kHz) 

20 Hz Frequency Range of Human Hearing 20 kHz

Equal Loudness Contour 


The Dyne 

� The amount of force required to move the eardrum is 

very small 

� The unit of measurement for that force is called a Dyne 

(abbreviated dyn) and is the amount of force required to 

accelerate a mass of 1 gram at a rate of one centimeter 

per second squared 

� 1 dyn = 1g x cm/s 2 

� The smallest amount of force our eardrum is capable of 

recognizing as a sound is 0.0002 dyn/cm 2 

� Threshold of Hearing 


The Dyne 

� We are capable of discerning sounds up to around 

200,000 dyn/cm2 

� That’s an increase of 1,000,000,000 times 

� If we used a linear scale to measure loudness, then we 

would need 1 Billion units 

� Since… 

� We prefer to work with smaller numbers, and… 

� Our hearing perception is non-linear (we are better at 

discerning changes in amplitude at lower levels than we are at 

higher levels)… 

� A logarithmic system is used to measure loudness 


The Decibel 

� The Decibel is the logarithmic scale used to measure 

loudness 

� Decibel = 1/10 th of a Bel (deci – bel) 

� Uses a common-log, or base10 log 

� Provides a much smaller set of numbers for measurement 

� For sound, approx. 180 values instead of 1,000,000,000 values 

� Provides greater resolution and sensitivity at lower levels than 

at higher levels, just like our hearing 

� dB is the standard abbreviation for Decibel 

� (Note: lower-case d, upper-case B) 

� There are different types of Decibels, but when we 

measure loudness we use dB SPL (Sound Pressure Level) 


Dynes vs. Decibels 

Using Dynes to measure SPL Using Decibels to measure SPL 


The Decibel 

� Decibels always compare the Amplitude of one wave to 

the Amplitude of another wave 

� When we use dB SPL, we are comparing a sound’s 

amplitude to the amplitude of the quietest sound a 

“typical” human can hear; the Threshold of Hearing 

� 0.0002 dn/cm 2 = 0dB SPL = Threshold of Hearing 

� dB SPL Formula 

� 20 log 10 

A 1 

A 0 

� A 1 = Measured Amplitude, A 0 = Threshold of Hearing 


dB SPL Rules of Thumb 

� With dB SPL, an increase of 20dB is a 10-fold increase in 

amplitude 

� This is different than some other forms of the decibel like dBm 

where a 10dB increase is a 10-fold increase in power 

� We’ll get to that in another class 

� A 6 dB increase is a doubling of amplitude 

� Because our hearing is non-linear, we won’t hear the sound as 

twice as loud 

� A 6 dB decrease is a halving of amplitude 

� Because our hearing is non-linear, we won’t hear the sound has 

half as loud 


dB SPL Meter 


One of the most popular db SPL Meters 

Radio Shack Model 33-4050

Common db SPL values 

dB SPL Sound Source (with distance) 

70 Busy traffic at 5 meters 

60 Office or restaurant inside 

50 Quiet restaurant inside 

40 Residential area at night 

30 Theater, no talking 

20 Only rustling of leaves 

10 Human breathing at 3 meters 

0 Threshold of Hearing (human with good ears) 


Common db SPL values 

dB SPL Sound Source (with distance) 

180 Rocket engine at 30 meters 

150 Jet engine at 30 meters 

130 Threshold of pain 

120 Rock concert; Jet aircraft taking off at 100 meters 

110 Accelerating motorcycle at 5m; Chainsaw at 1meter 

100 Pneumatic hammer at 2 meters; Inside disco 

90 Loud factory; Heavy truck at 1meter 

80 Vacuum cleaner at 1meter; Curbside of busy street 


Amplitude Measurements 


Peak (1.0) 

Average (0.637) 

� Peak – full amplitude from zero crossing 

� Average – arithmetic average of all positive values for a 

given amount of time

Hearing Amplitude 

Our ears do a natural average of amplitudes 


Actual 

Peak 

Amplitudes 

Average 

“Hearing” 

Amplitudes

Measuring Amplitude 

� Although the Peak Reading Meter is more 

accurate for precisely measuring amplitude, 

the slower VU Meter more closely represents 

how we “hear” amplitude 


VU Meter 

Peak Meter

Directional Perception 


Directional Perception 


Sound Localization 

Binaural Imaging 

� One ear cannot determine the direction of a sound, it 

takes two ears 

� The subtle differences between sounds arriving at the two 

ears is used by the brain to help locate a sound in space 

� Interaural Intensity Differences (Left/Right) 

� Mid and High Frequency Sounds 

� Interaural Arrival-Time Differences (Left/Right) 

� Low Frequency Sounds 

� Pinna and Ridge Reflection Delays 

� Front/Back and Up/Down Positioning 


Interaural Intensity Difference 

Acoustic 

Shadow 


High Frequency 

Sound Source 

Sound is louder in 

the right ear than 

in the left ear

Interaural Arrival-Time Difference 


Low Frequency 


Sound reaches the 

right ear before it 

reaches the left ear

Pinna and Reflective Ridge Delays 

Pinna 


Outer Ridge 

Inner Ridge 

Ridge reflections help 

with Front/Back and 

Up/Down localization

Phantom Imaging 

� Depending on how we distribute a sound between two 

speakers symmetrically positioned in front of us, we can 

trick the ear into thinking there is sound being created 

between the two speakers 

Left Speaker Phantom Image 

Right Speaker 


Perception of Space 


Perception of Space 

� Direct Sound 

� Sound that radiates directly from vibrating body to your ears 

� Gives primary “tonal” information about the sound 

� Early Reflections 

� The first set of reflections from the vibrating body that bounce 

off one surface before reaching your ears 

� Usually happen within 50ms of the direct sound 

� Give a sense of distance from sound source 

� Reverberation 

� Random, weak reflections from all surfaces in the room 

� Give a sense of room size and construction (wood, stone, 

carpet, etc.) 


Masking 

Occurs when one sound prevents us from properly hearing 

another sound 

� Amplitude Masking 

� Loud sound covers up soft sound 

� Spectral Masking 

� Two sounds with similar frequency content are difficult to 

distinguish 

� Temporal Masking 

� Time-based 

� Short, loud sound will continue to mask even after it has 

stopped 


Amplitude Masking 

Loud sounds make it difficult to hear soft sounds 

� In a mix, how important is the soft sound? 

� Very Important: adjust levels, pan positions, or both so that 

both sounds can be heard 

� Somewhat Important: can remain in background as part of 

ambient sound 

� Unimportant: does it really need to be in the mix? 


Spectral Masking 

When two sounds have a similar frequency content, the 

sound that is even slightly louder, or has a more percussive 

attack, tends to cover the other sound 

� Many instruments like guitars and keyboards play in the 

same frequency range and can mask each other 

� Separate them from each other with Pan Position 

� Use EQ to slightly alter the frequency content of the individual 

sounds so that they are different from each other 


Temporal Masking 

Just as a bright flash can temporarily blind our eyes, a 

strong, short blast of sound can temporarily deafen our 

ears, even after the sound has stopped 

� Compress, or turn 

down sounds that 

cause Temporal Masking 

� Snare Drum Hit 

� Vocal Plosive 


Amplitude 

Backward 

Masking 

Duration of 

Masking Tone 

50ms 

Forward 

Masking 

200ms 

Time

Sound Wavelength 

� The distance a sound wave travels in the amount of time 

it takes to complete one Wave Period 

� Sound travels at 1125 fps 

� A 100Hz wave has a Wavelength of 11.25 feet 

� 1125 ÷ 100 = 11.25 

� A 1000Hz wave has a Wavelength of 1.125 feet 

� 1125 ÷ 1000 = 1.125 

1.125’ 


11.25’

Sound Wavelength 

� Due to air molecule resistance, each time a sound wave 

completes a period, it loses some energy. 

� A sound with a long wavelength maintains its energy for a 

greater distance 

� A sound with a short wavelength loses its energy in a shorter 

distance 

� Low frequencies travel much farther than high frequencies 

� Harder to isolate 

� Car stereo “boom” effect 


Inverse Square Law 

� Sphere #2 Radius is twice the Radius of Sphere #1, but… 

� Sphere #2 Surface Area is four times the Surface Area of 

Sphere #1 

� The sound energy of Sphere #1 is now spread to an area four 

times larger, even though the distance from the sound source 

(radius) has only doubled 


Complex Sound Waves 

� Pure sine waves only exist in theory 

� Actual sounds are made up of an infinite number of sound 

waves at different frequencies and amplitudes 

� The combination of two or more waves is simply the sum 

of each wave’s amplitude at a given point in time 

� Reinforcement 

� Interference/Cancelation 

� Summed wave amplitudes yield a complex shaped wave 



Wave 1 

Wave 2 

Wave Sum 



Wave 1 

Wave 2 

Wave 3 

Wave Sum 


Sound Wave Phase Position 

0º Phase 

(or 360º) 

90º Phase 

� Position in the cycle of a wave is measured in degrees. 

� 0º - Beginning of Compression Phase = 360º - End of Rarefaction Phase 

� 90º - Peak of Compression Phase 

� 180º - Beginning of Rarefaction Phase 

� 270º - Peak of Rarefaction Phase 


180º Phase 

270º Phase 

360º Phase 

(or 0º)

Sound Wave Phase Position 

� Red wave is approx. 20º out of phase from blue wave 


Sound Wave Phase Cancellation 

� Red wave is 180º out of phase from blue wave causing 

complete cancellation of both waves’ energy 


Sound Wavelength/Standing Waves 

� Parallel reflective surfaces emphasize sound waves whose 

wavelength is the same as the distance between the 

parallel surfaces 

� Singin’ in the shower 

� Control Rooms and Live Rooms 

� 20’ = 56.25Hz 

� 12’ = 93.75Hz 

� 8’ = 141Hz 


Room Dimensions 

20’ 

12’ 

8’

Resonant Frequency 

� Tendency of a system to oscillate with high amplitude 

when excited by energy at a certain frequency 


Standing Waves in Resonant Bodies 

� Guitar Body Vibrations 



Tacoma Narrows Bridge • November 7, 1940 




Behavior of Sound Waves 

� A sound wave doesn't stop when it encounters an 

obstacle in its path. 

� Behaviors include reflection off the obstacle, 

diffraction around the obstacle, and transmission into 

the obstacle or new medium. 

� When a wave reaches the boundary between one 

medium and another medium, a portion of the wave 

undergoes reflection and a portion of the wave 

undergoes transmission across the boundary. 


Reflection of Sound 

� Incident sound and reflected sound 

� Smooth flat surface 

� Convex surface 


Reflection of Sound 

� Concave Surface 

� 90º Corner 


Diffraction of Sound 


Shorter wavelength of piccolo is 

more directional 

Longer wavelength of bass drum 

bends around obstructions 

Hears Bass Drum long before Piccolo

Effects Processing 

MUEA 474a • Electronic Synthesizer Techniques


� Alters the audio for corrective or creative purposes 

� Fix problems in recorded audio 

� Achieve natural-sounding effects 

� Create new sounds and effects 

� Alters 

� Frequency Content 

� Level 

� Time 

� Noise 

Effects Processing

Time-Based Effects 

� Delay a copy of the sound (or multiple copies of the 

sound) and recombine the delayed sound with the original 

(non-delayed) sound 

Signal 


Effect 

Level Controls 

Adjust ratio of 

Original (dry) 

signal to Delayed 

(wet) signal and 

combine into mix 

Mix Bus

Time-Based Effects 

� Delay 

� Phaser 

� Chorus 

� Flanger 

� Reverb 

Effects Processing

Delay 

Delay times can range from microseconds to seconds 

� Long Delay 

� Creates a distinct “echo” of the original sound 

� Medium Delay 

� Creates a doubling—often rhythmic—of the original sound 

� Short Delay 

� Not heard as a distinct sound 

� Phase cancellations alter the timbre of the sound 

� Comb Filter 

� Often used to “thicken” a sound 

Effects Processing

Comb Filter 

When short delays are applied to a sound, it creates phase 

cancellations at various points along the harmonic spectrum 

� “Metallic” sound 

� Looks like a comb on spectrograph 

500 Hz Tone 

Effects Processing

Comb Filter 

When short delays are applied to a sound, it creates phase 

cancellations at various points along the harmonic spectrum 

� “Metallic” sound 

� Looks like a comb on spectrograph 

500 Hz Tone 

w/ 2ms Delay 

Effects Processing

Common Delay Effects 

� Slap (or Tap) delay: delay time that allows a repeat of the 

sound to be heard 

� Rhythmic: delays are based on a rhythmic value (8 th -note, 

16 th -note, etc.) 

� Stereo: Original sound on one side, delayed sound on the other 

side 

� Phaser: Out of phase signal (creating a comb filter effect) 

is mixed back with the original, but at a constantly 

changing ratio controlled by a LFO 

� Flanger: A constantly changing short delay time causes 

the comb filter to shift 

� Chorus: Short delay times with LFO controlled pitch shift 

or detuning 

Effects Processing

Delay Sounds 

� Original Audio 

� Simple Delay 

� Slap Delay 

� Rhythmic Delay 

� Phaser 

� Flanger 

� Chorus 

Effects Processing

Delay Feedback 

� Sends some of the delayed signal back into the delay 

process to further “thicken” the result 

Effects Processing

Reverb 

� Direct signal 

� Early reflections 

Effects Processing

Reverb 

� Reverberation 

Effects Processing

Amplitude 

Reverb 

Early Reflections Reverberation 


Time

Anechoic Chamber 

Effects Processing

Reverb Types 

� Hall 

� Chamber/Room 

� Stage 

� Church 

� Arena 

� Stadium 

� Cave 

� Spring 

� Plate 

� Etc.! 

Effects Processing

Concert Hall 

Effects Processing

Chamber/Room 

Effects Processing

Chamber/Room 

Effects Processing

Chamber/Room 

Effects Processing

Stage 

Effects Processing

Spring Reverb 

Effects Processing

Plate Reverb 

Effects Processing

Common Reverb Controls 

� Wet/Dry mix 

� Ratio of the original (direct) sound to the reverberant sound 

� Affects perceived distance from the sound source 

� Decay or RT 60 time 

� The length of time it takes the entire reverb level to drop 60dB 

� Affects perceived size of the room 

� Size 

� Decay time for reverb tail only (independent of early 

reflections) 

� Affects perceived size of the room (fine tuning) 

Effects Processing

Common Reverb Controls 

� Pre-Delay 

� The length of time between the direct sound and the first early 

reflection 

� Affects perceived location of sound source in room 

� Frequency Damping 

� EQ adjustments of high and/or low frequencies in the 

reverberation 

� Affects perceived surface type of room 

� Envelope 

� Applies an envelope generator (Attack, Sustain, Release) to the 

reverb effect 

� Used for effects like “Gated Snare” sounds 

Effects Processing

Dynamics Processors 

� Dynamic Range 

� The difference between the lowest and highest levels in a 

sound 

� Factors 

� Noise floor 

� Signal Level 

� Operating level (0 VU) 

� Headroom 

� Clipping, distortion, or saturation 

Effects Processing

Dynamics Processors 

� Compressor 

� Reduces the dynamic range of a signal 

� Limiter 

� Prevents a signal from exceeding an established level 

� Expander 

� Increases the dynamic range of a signal 

� Gate 

� Mutes a signal when its amplitude falls below an established 

level 

Effects Processing

Compressor Threshold 

� Sets the amplitude level at which the compressor begins 

to turn down the level of the incoming sound 

� Threshold Concepts 

� Incoming audio that exceeds the Threshold level is turned 

down 

� Incoming audio that is below the Threshold level is unaffected 

� To only compress peaks, set Threshold high 

� To compress everything, set Threshold low 

Effects Processing

Threshold 

Above Threshold Below Threshold 


Threshold 

Uncompressed Kick Drum

Threshold 

Above Threshold Below Threshold 


Threshold 

Compressed Kick Drum

Ratio 

� Determines how much the incoming sound will be turned 

down when it rises above the Threshold level 

� Mathematical Expression 

� Input Amplitude:Output Amplitude 

� 1:1 No Compression 

� 2:1 for every 2dB increase on input, there is a 1dB increase on 

output – Light Compression 

� 8:1 for every 8dB increase on input, there is a 1 dB increase on 

output – Heavy Compression 

� Compressors with Ratios greater than 10:1 are considered 

Limiters 

Effects Processing

Ratio 

Effects Processing

Knee 

� Adjusts how smoothly or abruptly the compressor 

transitions from uncompressed sound to compressed 

sound, and back 

� Soft Knee 

� Gradual transition 

� Actually begins compressing below Threshold and doesn’t reach full 

ratio until above Threshold 

� Good for legato sounds like strings and vocals 

� Hard Knee 

� Abrupt transition 

� Instantly transitions from uncompressed to compressed (and back) as 

the audio level passes the Threshold level 

� Good for instruments with fast attacks like drums and keyboards 

Effects Processing

Knee 


Soft Knee

Knee 


Hard Knee

Attack Time 

� The amount of time that elapses before the compressor 

begins to attenuate the output level – after the threshold 

has been exceeded 

� For fast transients you need a shorter attack time (snare, 

handclaps) 

� If the attack time is long…you might miss the sound entirely 

� If the attack time is too short, a track can lose clarity resulting 

in a dull, lifeless quality 

Effects Processing

Release Time 

� The time the compressor takes to return to unity gain 

after the signal has fallen below the threshold 

� The purpose of the release time setting is to make the 

transition from compression to uncompressed signal 

imperceptible 

� Too slow of a release and everything gets compressed 

� Too fast of a release and you hear the compressor pump or 

“breathe” 

Effects Processing

Makeup Gain 

� Adjusts the final output level of the compressor 

� A compressor works by lowering the highest levels 

� Makeup Gain compensates for that reduction by bringing the 

entire level up 

� Loud sections are returned to their original level 

� Quiet sections are made louder 

Effects Processing

Special Compressors 

� Key Input and Side Chain Control 

� De-Esser 

� Ducker 

� Multi-Band Compression 

� Applies different amount of compression to different frequency 

bands 

� Often used to balance out the frequency spectrum of a mix in 

the mastering process 

Effects Processing

De-Esser 

� A frequency dependent Compressor/Limiter designed to 

control the transient peaks of sibilant speech (s, z, etc.) 

Effects Processing

Ducker 

� A Compressor whose action is triggered when a 

secondary, or “key” audio source goes above the 

Threshold 

Effects Processing

Multi-Band Compressor 

� Divides the audio into separate frequency bands and 

compresses each band individually 

Effects Processing

Limiter 

� A compressor whose output does not exceed a preset 

level, regardless of the input level 

� A compression ratio of between 10:1 and ∞ :1 

� Prevents short term peaks 

� Sets a maximum output level 

Effects Processing

Limiter 

Effects Processing

Expander 

� Increases dynamic range by turning low levels down and 

high levels up 

� The opposite of a Compressor 

� Levels above the Threshold are unaffected 

� Levels below the Threshold are turned down 

Effects Processing

Expander 

Effects Processing

Gate (Noise Gate) 

� An expander set to sharply reduce gain (mute) when the 

signal falls below the threshold 

� This results in the dramatic reduction of “noise” in the 

absence of a signal 

� Prevents “bleed through” from other instruments 

� Helps reduce background noise and clutter from the mix 

Effects Processing

Gate (Noise Gate) 

Effects Processing

Microphones 

MUIN 277x • Introduction to Music Technology

Microphone Abbreviations 

� It’s abbreviated “mic” 

� Please step up to the mic. 

� The plural is “mics” 

� We have several mics for you to try. 

� The possessive is “mic’s” 

� This mic’s polar patter is cardioid. 

� The past-tense verb is “miced” 

� I miced the guitar amp with an SM57. 

MUIN 277 – 08 Microphones

Microphone Types – Dynamic 

� Dynamic, or “Moving Coil” Microphone 

Diaphragm 

Sound 

Energy 

Voice Coil 

MUIN 277 – 08 Microphones 

Magnet 

Output Leads


� Microphone Characteristics 

� Rugged and reliable 

� Less sensitive to low volumes and fast transients 

� Tends to “warm up” the sound 

� Handles high volumes easily 

� Often used for drums, amplifiers and other loud instruments 

� Phantom power has no effect on the mic 




Shure SM57 

Sennheiser MD421

Microphone Types – Ribbon 

� Accordion-folded, metal ribbon 


Energy 


Magnet 

Output Leads 

Aluminum 

Ribbon 

Side View Front View



� Delicate 

� Fairly sensitive to low volumes and fast transients 

� Tends to “warm up” the sound 

� High volumes can damage the mic 

� Often used for vocals and acoustic instruments 

� Phantom power will damage or destroy the mic 




RCA 44B 

Royer R121

Microphone Types – Condenser 

� Measures change in capacitance 

Diaphragm 


Energy 

Backplate 


V 

– + 

Battery or Phantom Power 

+ ∆ V 

Output 

Leads



� Fairly rugged and reliable 

� Very sensitive to low volumes and fast transients 

� Detailed sound and frequency response, “accurate” 

� Easily handles both low and high volumes 

� Often used for vocals and acoustic instruments 

� Requires either a battery or phantom power to operate 




AKG C414 B-XL II 

Rode NT2A



Neumann KM184 

Neumann U87Ai


� Solid-state electronics 


AKG C414


� Vacuum-tube electronics 


Neumann U67

Diaphragm Size 

� Yes, size matters! 

� Small diaphragms (and ribbons) tend to be more accurate, have 

a flatter frequency response, and exhibit extend high-end and 

transient response 

� Small diaphragm mics are often used for “room” microphones 

when you want to capture the detail of a live room 

� Large diaphragms tend to have a fuller, more robust sound that 

is very pleasing in many instrumental and vocal applications 

� Large diaphragm mics are often used for “close-up” 

microphones when you want to capture the detail of a specific 

instrument or singer 


Diaphragm Size 

AKG C414 

Large Diaphragm 

3/4” or larger 


Rode NT3 

Medium Diaphragm 

5/8” to 3/4” 

Neumann KM184 

Small Diaphragm 

smaller than 5/8”

Microphone Polar Patterns 

Response 

Curve 

270º 

300º 

240º 


330º 

210º 

Front of Mic 

0º 

180º 

Back of Mic 

30º 

150º 

60º 

120º 

90º 

Diaphragm 

(not usually shown)

Omnidirectional Pattern 


Front of Mic 

Diaphragm Response 

Field 

The Omnidirectional Microphone hears 

in a 360º sphere around the diaphragm

Bidirectional or “Figure-8” Pattern 


Front of Mic 

The Bidirectional or “Figure-8” Microphone 

hears in front of and behind the diaphragm

Cardioid Pattern 


Front of Mic 

The Cardioid Pattern Microphone hears 

predominantly in front of the diaphragm

Supercardioid Pattern 

The Supercardioid Pattern Microphone hears mostly in front 

of the diaphragm, a little less to the side, and a small 

pickup area to the rear 


Front of Mic

Hypercardioid Pattern 

The Hypercardioid Pattern Microphone hears mostly in 

front of the diaphragm, with very little side pickup and a 

slightly larger pickup pattern to the rear 


Front of Mic

Boundary Microphone 

The Boundary Microphone is placed on a flat surface. 

Thus, it hears above and beside the diaphragm in a 

half-spherical pattern 


Top of Mic

Microphone Preamplifier (Preamp, Pre) 

� An amplifier used to boost the very weak (mic level) 

voltage coming from a microphone up to a level 

compatible with other electronic devices (line level) 


Grace M101 Microphone Preamp

Microphone Preamp Controls 

� Trim – turns up/down input signal from microphone 

� Gain – turns up/down output signal from preamp 

� 48V – turns Phantom Power on/off 

� Ribbon – bypasses Phantom Power and adds extra gain 

� For use with ribbon microphones 

� HPF – turns on/off High Pass Filter 

� Used to reduce low frequency sound (rumble, proximity effect) 

� Ø – inverts the phase of the signal 

� Mic/Line/Ins – selects input type 

� Microphone 

� Line (keyboards, electronic components, etc.) 

� Instrument (guitar, bass, acoustic pickups, etc.) 


Phantom Power (48V) 

� Phantom Power applies the same DC charge to both 

audio leads (pins 2 and 3) of the Condenser mic. Thus, it 

has no effect on the audio signal nor on the operation of 

dynamic microphones. 

� Phantom power can damage ribbon microphones 

XLR Pins 


48V DC 

Audio Leads 

6.81kΩ Resistors

Phantom Power 


Some microphones, especially tube mics, 

come with their own power supply

Microphone Frequency Response 

� A microphone’s ability to accurately capture audio 

frequencies is indicated with a “Frequency Response 

Curve” that usually comes with the microphone 

� Presence Peak 

� Certain frequency ranges that are boosted in relation to the 

other frequencies in the Frequency Response Curve 

� Proximity Effect 

� A boost of low frequencies from sound sources located very 

close to the microphone 


Microphone Frequency Response 

Relative Response in dB 

+10 

0 

-10 

2” from 


20 50 100 200 500 1k 2k 5k 10k 20k 


2’ from 


1kHz / 0dB 

Reference Point 

An example of a microphone Frequency Response Curve 

showing Proximity Effect and a Presence Peak around 5kHz

Microphone Terminology 

� Impedance (Z) 

� A microphone’s effective output resistance at 1kHz 

� Low impedance mics (150-600ohms) are generally best 

� Maximum SPL 

� The highest Sound Pressure Level (in dB) a microphone can 

handle without distortion 

� Sensitivity 

� The output voltage a microphone produces at a given SPL 

� A high sensitivity mic produces more voltage than a low 

sensitivity mic for the same SPL, and is usually quieter 


Microphone Terminology 

� Self Noise 

� The amount of electrical noise or hiss a microphone produces 

by itself 

� The lower the Self Noise, the quieter the microphone 

� Signal-to-Noise Ratio (SNR) 

� The difference (in dB) between a mic’s Sensitivity and its Self 

Noise 

� The higher the SNR, the more noise-free the signal 

� Polarity 

� The reference of the polarity of the electrical output signal to 

the acoustic input signal. The standard is “pin 2 hot.” That is, 

the mic produces a positive voltage at pin 2 (with respect to 

pin 3) when the sound pressure pushes the diaphragm in. 


Microphone Cables 


XLR – Balanced Cables

Microphone Shockmount 

Reduces Vibrations Picked Up by the Microphone 


Microphone Windscreen 


Helps Prevent Bursts of Air from Hitting the 

Microphone when Speaking or Singing

Microphone Techniques 


≠

Microphone Techniques 

There is no “ONE” way to use a microphone 

� Use your ears 

� Before placing the mic to find the “sweet spot” 

� After placing the mic to ensure it has the sound you want 

� Never be afraid to reposition a mic 

� Microphone choice considerations 

� Frequency response 

� Accuracy 

� Polar pattern 

� Transient response 

� Loudness Handling 


Microphone Placement 

� Close Mic Placement (“Studio” Sound) 

� Great detail of sound source 

� Noise from sound source 

� Little room sound 

� Proximity effect 

� Distant Mic Placement (“Live” Sound) 

� Unfocused sound from source 

� More ambient sound 

� Room noise 

� Potential for echoes, and phase cancellation 

� Loss of frequencies 


Microphone Placement 

� Position relative to sound source 

� Different sounds from source? 

� On axis/off axis 

� Ratio of source to room 

� Multiple Microphones 

� Stereo 

� Close/Distant 

� Different sounds from source 

� Different sounding microphones 

� Spacing – 3:1 rule 


Stereo Microphone Techniques 

A pair of microphones positioned to simulate 

the acoustic spacing created by our ears 

� Distant placement 

� Usually for recording ensembles and stage sounds 

� Orchestra or band recordings 

� Intermediate placement 

� For capturing the ambient sound around a source 

� Drum overheads, guitar amp room 

� Close placement 

� For creating a wide recording of a sound source 

� Piano, guitar, marimba, etc. 


Interaural Intensity Difference 


Acoustic 

Shadow 

High Frequency 


Sound is louder in 

the right ear than 

in the left ear

Interaural Arrival-Time Difference 


Low Frequency 


Sound reaches the 

right ear before it 

reaches the left ear

Stereo Speaker Placement 

Left 

Speaker 


Equilateral 

Triangle 

Right 

Speaker

Stereophonic Imaging 

A 

Left 

Speaker 


B 

Recorded 

Ensemble 

C 

Desired 

Imaging 

D 

E 

Right 

Speaker


Left 

Speaker 


A 

B 

Recorded 

Ensemble 

C 

Narrow 

Imaging 

D 

E 

Right 

Speaker


A 

Left 

Speaker 

B 


Recorded 

Ensemble 

C 

Exaggerated Width 

Imaging 

D 

E 

Right 

Speaker


Left 

Speaker 


Recorded 

Ensemble 

A B C D E 

Flattened 

Imaging 

Right 

Speaker

Microphone Elevation 

A B C D = A B C D 

A B C D = A B C D 


Low mic elevation creates expanded depth 

High mic elevation creates compressed depth

Phase Cancellation 

Stereo signal summed to mono 

can produce phase cancellations 


Stereo Microphone Pair 

receiving same audio 

at different time intervals 

+ =

Spaced Pair Technique 

D 



1/3-1/2 D 

3:1 Ratio 

C L

Coincident (X-Y) Technique 

X 



90 - 135˚ 

C L 

Y

Coincident (X-Y) Technique 


Rode NT4 Stereo Microphone

Blumlein* (X-Y) Technique 


X 


C L 

90˚ 

*Alan Dower Blumlein (1903-1942) 

Y

Blumlein (X-Y) Technique 


Manley Gold Reference Stereo Microphone

Mid-Side Pair Technique 



S S 

C L 

Stereo: M + S = L and M - S = R Mono: (M + S) + (M - S) = 2M

Mid-Side Pair Technique 

M/S Microphone Pair 

SCHOEPS MK4 Cardioid 

and MK8 Figure-8 


AEA MS38 Mark II 

Dual-Mode Matrix 

M/S Processor

Near-Coincident (ORTF*) Technique 



C L 

110˚ 

6.7” (17 cm) 

*Office de Radiodiffusion-Television Francaise

Near-Coincident (ORTF) Technique 

SCHOEPS MSTC 64g “ORTF Stereo” Microphone 


Binaural Technique 

Sound-Absorbent 

Baffle 



6.7” (17 cm) 

C L

Binaural Technique 


Neumann KU 100 Binaural Microphone

Final Exam Information 

� Review Session 

� Tuesday, May 4 th 4:00 – 6:00pm 

� Final Exam 

� Thursday, May 6 th @ 4:30pm 

� 100 question, multiple-choice 

� Covers the entire semester 

� Approximately 50 questions from this last unit 

� Approximately 50 questions from the previous two units 

MUIN 277 – 27 Intellectual Property & Copyright

Intellectual Property & Copyright 

MUIN 277x • Introduction to Music Technology

Intellectual Property (IP) 

� Legal property rights over creations of the mind, both artistic 

and commercial 

� Under intellectual property law, owners are granted certain 

exclusive rights to a variety of intangible assets 

� Musical, literary, and artistic works 

� Ideas, discoveries and inventions 

� Words, phrases, symbols, and designs 

� Includes copyrights, trademarks, patents, industrial design 

rights, and trade secrets 


Copyright © 

� The Congress shall have power to promote the 

progress of science and useful arts, by securing for 

limited times to authors and inventors the exclusive 

right to their respective writings and discoveries 

– U. S. Constitution, Article 1, Section 8, Clause 8 


Copyright © 

� Copyright is a form of protection grounded in the 

U.S. Constitution and granted by law for original 

works of authorship fixed in a tangible medium of 

expression 

� Copyright covers both published and unpublished 

works 

� Copyrights are governed by both national and 

international laws 

� Copyright determines who has the right to make a 

copy of a protected work 


Copyright © 

� The five "pillars" of copyright 

� The owner of copyright has the exclusive right to do and 

to authorize others to do the following five things 

1. To reproduce the work in copies or phonorecords 

2. To prepare derivative works based upon the work 

3. To distribute copies or phonorecords of the work to the 

public by sale or other transfer of ownership, or by rental, 

lease, or lending 

4. To publicly perform the work, in the case of literary, musical, 

dramatic, and choreographic works, pantomimes, and motion 

pictures and other audiovisual works, and sound recordings 

by means of digital audio transmission 

5. To publicly display the work, in the case of literary, musical, 

dramatic, and choreographic works, pantomimes, and 

pictorial, graphic, or sculptural works, including the individual 

images of a motion picture or other audiovisual work 


Copyright © 

� Copyright protects original works of authorship 

including literary, dramatic, musical, and artistic works, 

such as poetry, novels, movies, songs, computer 

software, and architecture 

� Copyright does not protect facts, ideas, systems, or 

methods of operation, although it may protect the 

way these things are expressed 


Copyright © 

� Copyright protection begins the moment the work is 

created and fixed in a tangible form that it is 

perceptible either directly or with the aid of a 

machine or device 

� You do not need to register a work to own the 

copyright 

� Copyright registration may make it easier to claim 

damages in court in the event of an infringement 


Copyright © 

� Individual Copyright (works created after Jan. 1, 1978) 

� Copyright protection lasts for the life of the author plus an additional 70 

years 

� Corporate Copyright (works created after Jan. 1, 

1978) 

� Copyright protection lasts for a term of 95 years from the year of its 

first publication or a term of 120 years from the year of its creation, 

whichever expires first 

� Copyrights are no longer renewed for works created 

after Jan. 1, 1978 


Copyright © 

� © Copyright Symbol for original works of authorship 

� ℗ Copyright Symbol for sound recordings 

� ® Copyright Symbol for registered names and brands 

Copyright © 2010 Brian K. Shepard 


Derivative Work 

� A work that is based on (or derived from) one or 

more already existing works 

� Copyrightable if it includes what the copyright law 

calls an “original work of authorship” 

� Derivative works, also known as “new versions,” include 

such works as translations, musical arrangements, 

dramatizations, fictionalizations, art reproductions, and 

condensations 

� Any work in which the editorial revisions, annotations, 

elaborations, or other modifications represent, as a whole, 

an original work of authorship is a derivative work or new 

version 


Fair Use 

� Under the fair use doctrine of the U.S. copyright 

statute, it is permissible to use limited portions of a 

work including quotes, for purposes such as 

commentary, criticism, news reporting, and scholarly 

reports 

� There are no legal rules permitting the use of a 

specific number of words, a certain number of musical 

notes, or percentage of a work. Whether a particular 

use qualifies as fair use depends on all the 

circumstances 


Fair Use 

� Elements of Consideration 

� The purpose and character of the use, including whether such use is of 

commercial nature or is for nonprofit educational purposes 

� The nature of the copyrighted work 

� The amount and substantiality of the portion used in relation to the 

copyrighted work as a whole 

� The effect of the use upon the potential market for or value of the 

copyrighted work 


Fair Use Consideration 

� Quotation of excerpts in a review or criticism for 

purposes of illustration or comment 

� Quotation of short passages in a scholarly or 

technical work, for illustration or clarification of the 

author's observations 

� Use in a parody of some of the content of the work 

parodied 

� Summary of an address or article, with brief 

quotations, in a news report 


Fair Use Consideration 

� Reproduction by a library of a portion of a work to 

replace part of a damaged copy 

� Reproduction by a teacher or student of a small part 

of a work to illustrate a lesson 

� Reproduction of a work in legislative or judicial 

proceedings or reports 

� Incidental and fortuitous reproduction, in a newsreel 

or broadcast, of a work located in the scene of an 

event being reported 


Copy Protection 

� Until very recently, copyrighted items were protected 

as much by the difficulty of copying as by any 

copyright laws 

� Copying items was labor-intensive and timeconsuming 

� Errors often crept into the copies 

� Quality of copies was frequently, obviously inferior to 

the original 



� When copying was done 

by hand, the sheer effort of 

making a copy prevented 

most unauthorized copying 

� No method for copying 

sound existed 



� Even with the printing press, 

the quality of copies varied 

greatly and the amount of 

effort to set the type proved 

prohibitive for most people 

� No method for copying 

sound existed 



� The tape recorder finally 

allowed people to record 

—and re-record—music, 

although it’s cost and 

impracticality tended to 

limit the number of music 

recordings that were 

copied 



� The cassette tape changed 

everything 

� For the first time, average 

consumers could copy music 

inexpensively and with 

relative ease 

� Although the quality of the 

recording is not great, it was 

sufficient for the time 

MUIN 277 – 27 Intellectual Property & Copyright 

Introduced 1963


� The CD had been around 

since 1979, but it was the 

introduction of the CD- 

Recordable Disk and CD-R 

Drives in 1988 that allowed 

the average consumer to 

make an exact digital 

replication of a song or file 

both quickly and 

inexpensively 

MUIN 277 – 27 Intellectual Property & Copyright 

CD-R Introduced 1988


� The Internet has enabled the 

instantaneous access to, and 

distribution of, music and 

software on an 

unprecedented level 

� Both legal and illegal copying 

and distribution are 

flourishing on the Internet 


CD Recordings (Example Warnings) 

� Unauthorized duplication and use prohibited. 

� All rights preserved. Unauthorized copying, 

reproduction, hiring, renting, public performance and 

broadcasting prohibited. 

� All rights of the owner of the work reproduced 

reserved. Unauthorized copying, lending, public 

performance and broadcasting of this work 

prohibited. 


Software License Agreement 

Cycling '74 Max/MSP License Agreement 

This License Agreement governs use of Max/MSP software. 

IMPORTANT: PLEASE READ THIS SOFTWARE LICENSE AGREEMENT CAREFULLY BEFORE USING THE SOFTWARE. BY USING THE SOFTWARE, YOU ARE AGREEING TO BE BOUND BY THE TERMS AND CONDITIONS STATED BELOW. IF YOU DO NOT AGREE WITH THE TERMS OF THIS LICENSE, DO NOT INSTALL THE SOFTWARE. 

1. License. Cycling '74, a California corporation ("CYCLING74") grants to the Licensee purchasing this copy of Max/MSP a nonexclusive, nontransferable license to use such Max/MSP software and the Max/MSP Software Development Kit supplied herewith (the "Software") and the associated documentation solely in accordance with this License. CYCLING74 and CYCLING74's Licensors 

retain title to the Software and related documentation although the Licensee owns the media on which the Software and documentation are recorded, if any. Only the number of Users for which Licensee has paid the applicable license fees may use the Software and documentation. "User(s)" means Licensee, if Licensee is an individual purchasing the Software for use at office or home (in 

which case Licensee's immediate family members residing in the same household shall not be considered additional Users), or, if Licensee is a corporation or similar business or commercial entity or government agency, its current employees. For qualifying educational institutions, "Users" also means faculty and staff teaching for or employed by Licensee and registered students enrolled at a 

single campus operated by Licensee. Subject to the limitations of this License, each authorized User may only use the Software on (i) any central processing unit ("CPU"), workstation or portable computer that is owned or controlled by Licensee, and (ii) any User-owned CPU, workstation or portable. This license does not grant Licensee the right to sell, resell, or license Max/MSPcompatible 

objects, or Max/MSP-derived plug-ins or standalone software applications to multiple customers. Commercial distribution of objects, plug-ins, or standalone software applications, or any other use not expressly granted herein, is prohibited without an express grant of rights by CYCLING74 in its sole discretion subject to the terms and conditions of a separate written 

Commercial License Agreement, which can be obtained by contacting CYCLING74 business office, or by e-mail at admin@cycling74.com. 

2. Runtime License. The Max/MSP/Jitter Runtime software may be copied and/or re-distributed in conjunction with User’s Max/MSP/Jitter-derived software application(s). It may not be sold, either by itself, or in conjunction with User’s application, without written permission from CYCLING74 in the form the Commercial License Agreement referenced above. 

3. Restrictions. This License sets forth the terms and conditions governing the use of the Software and documentation. Licensee may not use, reproduce in copies, adapt, distribute, perform, or display the Software other than as expressly stated in this License. Licensee may not rent, lease or otherwise transfer the Software or its documentation. Licensee may make only that number of 

copies of the Software equal to the number of licensed Users and two (2) back-up or archival copies. The Software contains copyrighted works of authorship, trade secrets and other proprietary information of CYCLING74. Licensee shall not make copies of the copyrighted Software documentation without the prior written permission of CYCLING74 provided that for electronic 

transactions, Licensee may make one (1) printed copy of such documentation for each User. 

4. Technical Support. If the Licensee purchases an authorization for unlimited use of the Software directly from CYCLING74, Licensee is automatically registered and may receive technical support via electronic mail for a period of one (1) year from date of purchase, provided that Licensee sends inquiries from the electronic mail address specified on the original order form, or provides a 

Customer Serial Number or other identifying information. Upon the expiration of the above-described one (1) year period, Licensee may extend technical support on a per-incident or annual fee basis in accordance with CYCLING74's then-current pricing and terms. Upgrades to the Software and its documentation, if any, are not included and may be sold separately. For copies of the 

Software sold through suppliers other than Cycling '74, Licensee is entitled to one (1) year of technical support after registering with Cycling '74 by sending an electronic mail message to support@cycling74.com containing Licensee's name, electronic mail address and Customer Serial Number or by using the web-based registration form at http://www.cycling74.com. 

5. Termination. This License is effective until terminated by either CYCLING74 or Licensee. Licensee may terminate this License at any time by destroying all copies of the Software and its documentation. This License will terminate immediately without notice from CYCLING74 if Licensee fails to comply with any provision of this License. Upon termination, Licensee must destroy all copies 

of the Software and its documentation. 

6. Disclaimer of Warranty. Licensee makes no warranties of any kind with respect to any effect that use of Software may have on third party software or applications with which Software is used. Licensee expressly acknowledges and agrees that the use of the Software and its documentation is at Licensee's sole risk. The Software, documentation, and technical support are provided "AS IS" 

and without warranty of any kind. TO THE MAXIMUM EXTENT PERMITTED UNDER APPLICABLE LAWS, CYCLING74 AND CYCLING74'S LICENSOR(S) (FOR THE PURPOSES OF SECTIONS 5 AND 6, CYCLING74 AND CYCLING74'S LICENSOR(S) SHALL BE COLLECTIVELY REFERRED TO AS CYCLING74) EXPRESSLY DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 

INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NONINFRINGEMENT. CYCLING74 DOES NOT WARRANT THAT THE FUNCTIONS CONTAINED IN THE SOFTWARE WILL MEET LICENSEE'S REQUIREMENTS, OR THAT THE OPERATION OF THE SOFTWARE WILL BE 

UNINTERRUPTED OR ERROR-FREE, OR THAT DEFECTS IN THE SOFTWARE WILL BE CORRECTED. FURTHERMORE, CYCLING74 DOES NOT WARRANT OR MAKE ANY REPRESENTATIONS REGARDING THE USE OR THE RESULTS OF THE USE OF THE SOFTWARE OR ITS DOCUMENTATION IN TERMS OF THEIR CORRECTNESS, ACCURACY, RELIABILITY, OR 

OTHERWISE. NO ORAL OR WRITTEN INFORMATION OR ADVICE GIVEN BY CYCLING74 OR ITS AUTHORIZED REPRESENTATIVE SHALL CREATE A WARRANTY OR IN ANY WAY INCREASE THE SCOPE OF THIS WARRANTY. SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES, SO THE ABOVE EXCLUSION MAY NOT APPLY. 

7. Limitation of Liability. TO THE MAXIMUM EXTENT PERMITTED UNDER APPLICABLE LAWS, UNDER NO CIRCUMSTANCES, INCLUDING NEGLIGENCE, SHALL CYCLING74 BE LIABLE FOR ANY INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES (INCLUDING DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS 

INFORMATION AND THE LIKE) ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE OR ITS DOCUMENTATION, EVEN IF CYCLING74 OR ITS AUTHORIZED REPRESENTATIVE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME JURISDICTIONS DO NOT ALLOW THE LIMITATION OR EXCLUSION OF LIABILITY FOR INCIDENTAL 

OR CONSEQUENTIAL DAMAGES SO THE ABOVE LIMITATION OR EXCLUSION MAY NOT APPLY. In no event shall CYCLING74's total liability to Licensee for all damages, losses, and causes of action (whether in contract, tort, including negligence, or otherwise) exceed the amount paid by Licensee for the Software and its documentation. 

8. No Waiver or Assignment. No delay or failure to take action under this License will constitute a waiver unless expressly waived in writing, signed by a duly authorized representative of CYCLING74, and no single waiver will constitute a continuing or subsequent waiver. This License may not be assigned, sublicensed or otherwise transferred by Licensee, by operation of law or otherwise, 

without CYCLING74's prior written consent, provided that Licensee may assign this License upon written notice to CYCLING74 in instances in which such assignment is to an entity which acquires all or substantially all of the business of Licensee, whether by merger, consolidation, or acquisition of assets. 

9. Controlling Law and Severability. This License shall be governed by and construed in accordance with the laws of the United States and the State of California, as applied to agreements entered into and to be performed entirely within California between California residents. If for any reason a court of competent jurisdiction finds any provision of this License, or portion thereof, to be 

unenforceable, that provision of the License shall be enforced to the maximum extent permissible so as to effect the intent of the parties, and the remainder of this License shall continue in full force and effect. 

10. Entire Agreement. This License constitutes the entire agreement between the parties with respect to the use of the Software and its documentation, and supersedes all prior or contemporaneous understandings or agreements, written or oral, regarding such subject matter. There shall be no contract for purchase or sale of the Software except upon the terms and conditions specified 

herein. Any additional or different terms or conditions proposed by Licensee or contained in any purchase order are hereby rejected and shall be of no force and effect unless expressly agreed to in writing by CYCLING74. No amendment to or modification of this License will be binding unless in writing and signed by a duly authorized representative of CYCLING74. 

Copyright © 2002 Cycling ’74. All rights reserved. Cycling ’74, Max, MSP, and Jitter are trademarks of Cycling ’74. 



Cycling '74 Max/MSP License Agreement 

This License Agreement governs use of Max/MSP software. 

IMPORTANT: PLEASE READ THIS SOFTWARE LICENSE 

AGREEMENT CAREFULLY BEFORE USING THE SOFTWARE. 

BY USING THE SOFTWARE, YOU ARE AGREEING TO BE 

BOUND BY THE TERMS AND CONDITIONS STATED 

BELOW. IF YOU DO NOT AGREE WITH THE TERMS OF THIS 

LICENSE, DO NOT INSTALL THE SOFTWARE. 



1. License. Cycling '74, a California corporation ("CYCLING74") grants to the Licensee purchasing this copy of 

Max/MSP a nonexclusive, nontransferable license to use such Max/MSP software and the Max/MSP Software 

Development Kit supplied herewith (the "Software") and the associated documentation solely in accordance 

with this License. CYCLING74 and CYCLING74's Licensors retain title to the Software and related 

documentation although the Licensee owns the media on which the Software and documentation are recorded, 

if any. Only the number of Users for which Licensee has paid the applicable license fees may use the Software 

and documentation. "User(s)" means Licensee, if Licensee is an individual purchasing the Software for use at 

office or home (in which case Licensee's immediate family members residing in the same household shall not be 

considered additional Users), or, if Licensee is a corporation or similar business or commercial entity or 

government agency, its current employees. For qualifying educational institutions, "Users" also means faculty and 

staff teaching for or employed by Licensee and registered students enrolled at a single campus operated by 

Licensee. Subject to the limitations of this License, each authorized User may only use the Software on (i) any 

central processing unit ("CPU"), workstation or portable computer that is owned or controlled by Licensee, 

and (ii) any User-owned CPU, workstation or portable. This license does not grant Licensee the right to sell, 

resell, or license Max/MSP-compatible objects, or Max/MSP-derived plug-ins or standalone software applications 

to multiple customers. Commercial distribution of objects, plug-ins, or standalone software applications, or any 

other use not expressly granted herein, is prohibited without an express grant of rights by CYCLING74 in its 

sole discretion subject to the terms and conditions of a separate written Commercial License Agreement, 

which can be obtained by contacting CYCLING74 business office, or by e-mail at admin@cycling74.com. 


Gamestation License Agreement 

� By placing an order via this Web site on the first day of 

the fourth month of the year 2010 Anno Domini, you 

agree to grant Us a non transferable option to claim, for 

now and for ever more, your immortal soul. Should We 

wish to exercise this option, you agree to surrender your 

immortal soul, and any claim you may have on it, within 5 

(five) working days of receiving written notification from 

gamesation.co.uk or one of its duly authorized minions. 

� The clause even contained an option to opt out, and 

Gamestation rewarded attentive customers with an $8 gift 

certificate for catching it. Gamestation says about 88-percent 

of the people who purchased from the site on April 1st 'lost 

their souls.' 


Digital Rights Management (DRM) 

� Usually some sort of software hidden code that attempts to 

restrict the ability to copy and/or distribute protected IP 

� FairPlay (iTunes) 

� Adobe Protected Streaming (Flash Media Server) 

� 3-play (Microsoft Zune) 

� Open Mobile Alliance (Cell Phone Ring Tones) 

� DRM-X (All Types of Media Formats for MS Windows) 

� Many, many more! 

� Nearly all have been hacked! 


Digital Rights Management (DRM) 

� Digital Millennium Copyright Act (DMCA) of 1998 

� The American implementation of the World Intellectual Property 

Organization (WIPO) Copyright Treaty 

� An extension to US Copyright law 

� Prohibits defeating and/or reverse engineering of DRM for the purpose 

of violating the rights of copyright holders 

� IP owners are frequently targeting large-scale violators of the 

DMCA with lawsuits that often reach the hundreds of 

thousands of dollars in fines and penalties 


DMCA Compliance at USC 

� Institutions that allow DMCA violations to occur are also 

being held liable for damages 

� Under the Digital Millennium Copyright Act (DMCA), The University of 

Southern California reserves the right to terminate computing services 

of users who repeatedly infringe upon the rights of copyright owners. 

For questions or concerns related to copyright compliance contact Ilee 

Rhimes, Chief Information Officer and Vice Provost for Information 

Technology Services, who is the designated agent to receive notification 

of copyright infringement claims. 

—http://www.usc.edu/its/policies/dmca/ 


Questions? 

� Remember, I’m not an lawyer 

� I don’t even get to play one on TV! 

� Always consult an attorney for real legal advice 

� Ignorance of the law is not a legitimate legal defense—you’ll 

lose 

� Just because you haven’t been caught doesn’t mean it’s legal 

� When in doubt, don’t copy and/or distribute 


Please, 

Don’t Steal Music 

and Software* 

*Or anything else, for that matter

Digital Audio 

MUSC 310 • Computer Recording for the Performing Musician

Analog 

A continuous, and often graphical representation (analogy) 

of a thing or concept 

Analog Speedometer Analog Clock 

MUSC 310 – 02 Digital Audio

Digital 

A momentary, periodic, and often numerical, representation 

of a thing or concept 

Digital Speedometer Digital Clock 


Acoustical to Electrical Conversion 

Recording equipment converts acoustical energy to 

electrical energy 

� Positive air pressure (compression) becomes positive voltage 

� Negative air pressure (rarefaction) becomes negative voltage 

Positive 

(Compression) 

Air Pressure 

(Rarefaction) 

Negative 

MUSC 310 – 02 Digital Audio 

Positive 

Voltage 

Negative

Analog Audio 

In Analog recording, voltage changes are stored in a 

continuous and physical medium; most frequently as 

� Grooves on a record 

� Dispersion of iron-oxide particles on magnetic tape 

Magnified Grooves on a Vinyl LP Illustration of Magnetic Tape Particles 


Digital Audio 

In Digital recording, voltage changes are stored as individual 

measurements, called samples, taken thousands of times per 

second. Each sample is then stored in a time-stamped 

memory location in binary format (0s & 1s) 

Sample # Sample Value 

1 

2 

3 

4 

5 

6 

7 

8 

Sequence of 16-bit samples in 

Binary Notation 


1001001101100101 

1001001101100110 

1001001101100011 

1001001101100101 

1001001101100111 

1001001101100110 

1001001101100101 

1001001101100011 

Magnified Pits and Lands on a CD 

Representing 0s and 1s

Nyquist Theorem 

In order to digitally capture an analog sound wave, you must 

take, at least, two samples of every wave period 

� That way, you measure both the compression and the rarefaction 

phase of each wave 

� The sampling rate frequency must be at least twice as high as the 

frequency of the highest sound wave to be recorded 


Sampling Rate 

� In the Digital Audio world, a Sample is a single 

measurement of a transduced soundwave’s voltage at a 

specific point in time 

� The Sampling Rate is the number of measurements 

taken per second 

� Since we can hear up to about 20kHz, we use a sampling 

rate that is at least 40kHz (Nyquist Theorem) 

� 44.1kHz (CD Audio) 

� 48kHz (Video and DVD Audio) 

� High-Definition Rates 

� 88.2kHz and 96kHz (2 X 44.1 and 48) 

� 176.4kHz and 192kHz (4 X 44.1 and 48) 


Sampling Rate 

Sampling is more accurate at low frequencies than at high 

frequencies 

� 44.1 kHz Sampling Rate 

� 100Hz wave = 441 samples per period 

� 1000Hz wave = 44.1 samples per period 

� 10,000Hz wave = 4.41 samples per period 


� 192 kHz Sampling Rate 






Bit Depth 

� The measurement of the voltage at a sample point is 

stored in Bits (short for “Binary Digits”) 

� Bits are the 1s and 0s that a computer uses for all 

calculations 

� Bits are usually strung together into larger groups called 

Digital Words or “Bytes” 

� Bit Depth refers to the number of Bits in each Byte 

� In Digital Audio, the most common Bit Depth is 16 bits 

� 16 1s and 0s (ex. 1101001010110100) 


Bit Depth 

� The more bits used for the measurement, the greater the 

accuracy of the measurement 

� 8 bit = 256 measurement units (0-255) 

� 16 bit = 65,536 measurement units (0-65,535) 

� 24 bit = 16,277,216 measurement units (0-16,277,215) 

� Each added bit doubles the dynamic range of the audio 

recording (adds 6dB) 

� 8 bit = 48dB 

� 16bit = 96db 

� 24bit = 144dB 


…but first, a little binary math refresher

Decimal (base 10) math 

� Counting system based on ten numerals 

� 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 

� Each “column” in a large number represents a 10 x power 

� 10 0 – ones 

� 10 1 – tens 

� 10 2 – hundreds (10 x 10) 

� 10 3 – thousands (10 x 10 x 10) 

� 10 4 – ten-thousands (10 x 10 x 10 x 10), etc. 

� 12,257 

� (1 X 10 4 ) + (2 X 10 3 ) + (2 X 10 2 ) + (5 X 10 1 ) + (7 X 10 0 ) 


10 4 10 3 10 2 10 1 10 0 

1 2 2 5 7

Binary (base 2) math 

� Counting system based on two numerals 

� 0, 1 (represented by negative and positive voltage) 

� Each “column” in a large number represents a 2 x power 

� 2 0 – ones 

� 2 1 – twos 

� 2 2 – fours (2 x 2) 

� 2 3 – eights (2 x 2 x 2) 

� 2 4 – sixteens (2 x 2 x 2 x 2), etc. 

� 12,257 = 0010111111100001 (16 bit) 

2 15 2 14 2 13 2 12 2 11 2 10 2 9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 

32768 16384 8192 4096 2048 1024 512 256 128 64 32 16 8 4 2 1 

0 0 1 0 1 1 1 1 1 1 1 0 0 0 0 1 


Counting in Binary 

Counting in binary is similar in many ways to counting in 

the base-10 system. Notice that instead of having the 1’s 

place, 10’s place, and so on, we have powers of 2’s instead 

(i.e. 2 0 ’s place is the right most digit, etc.) 

� 0 = 0000 0000 

� 1 = 0000 0001 = 2 0 

� 2 = 0000 0010 = 2 1 

� 3 = 0000 0011 

� 4 = 0000 0100 = 2 2 

� 5 = 0000 0101 

� 6 = 0000 0110 

� 7 = 0000 0111 

� 8 = 0000 1000 = 2 3 


� 9 = 0000 1001 

� 10 = 0000 1010 

� 11 = 0000 1011 

� 12 = 0000 1100 

� 13 = 0000 1101 

� 14 = 0000 1110 

� 15 = 0000 1111 

� 16 = 0001 0000 = 2 4 

� And so on…

Digitization 

Electrical analog wave enters the Analog-to-Digital Converter (ADC) where a 

clock pulsing thousands of times a second triggers a sampling device that 

measures the wave’s amplitude at each point in time rounded to the nearest 

amplitude increment. 


Digitization 





Clock Pulses 


Digitization 





Clock Pulses 

Amplitude 

Measurements 


Digitization 





Clock Pulses 

Amplitude 

Measurements 


Digitization 






Digitization 






Digitization 






Quantization Error 

The difference between the digitized sound wave and the original analog 

sound wave as a result of the sampling rate and rounding to the nearest 



Higher Resolution 

Increasing the Sampling Rate, the Bit Depth, or both, dramatically reduces 

quantization error. 

Amplitude 

Measurements 


Clock Pulses

Common Sample Rates & Bit Depths 

� 44.1kHz and 48kHz • Standard Digital Sampling Rates 

� 88.2kHz, 96kHz, 176.4kHz, and 192kHz • High Definition Rates 

� 8-bit • “Grunge” or “Retro” Resolution 

� 16-bit • Standard Resolution 

� 20-bit and 24-bit • High Resolution 

� 44.1kHz / 16-bit • “CD Quality” 

� 48kHz / 16-bit • “DAT or DV Quality” 

� 96kHz / 24-bit • “DVD-Audio 5.1 Quality” 

� 192kHz / 24-bit • “DVD-Audio Stereo Quality” 


Aliasing 

If the sampling rate is too low for the frequencies being recorded (below the 

Nyquist Theorem requirements), aliasing can occur. Aliasing is the creation of 

much lower–artificial–frequencies during the digital-to-analog or playback 

phase as a result of improperly sampled high frequencies. 


Aliasing 






Aliasing 






Digital Levels 

� Levels in Digital Audio are measured in dBfs (full scale) 

� The highest level Digital Audio can record is 0 dBfs 

� Digital Over (Digital Clipping) is when 2 or more 

consecutive samples are recorded at 0 dBfs 

� Since VU meters don’t move fast enough and only 

measure averages, they don’t report Digital Overs 

� Digital Peak Program Meters (PPM) are used to watch for 

clipping 

� On many devices, 0VU = -18 dBfs, but can frequently be 

changed 


Clipping 

When the incoming audio signal exceeds the bit 

resolution of the ADC, the measurements drop out 

temporarily creating a nasty, and harsh sound 


Normalizing 

Normalizing increases the digital signal so that the 

loudest sample is brought up to 0dBfs 


Original Audio File Normalized Audio File

Dither 

� Dither is a small amount of random noise added to the 

audio signal to lessen the effect of the Distortion caused 

by Quantization Error 

� Quantization Distortion is especially noticeable at low 

(quiet) signal levels 

� Reduces the “graininess” of Digital Audio during quiet 

passages, fades, and reverberation tails 

� In theory, increasing from 16 bit to 24 bit eliminates need 

for Dither 

� Currently, all consumer Digital Audio devices are 16 bit 

� Most professional recordings are now done at 24 bit and 

“Dithered Down” to 16 bit for distribution 


Word Clock 

In order to work correctly, all devices in the Digital 

Audio chain must have their sampling rate coordinated. 

Word Clock is a timing message shared between digital 

devices that keeps them synchronized. 

Jitter 

Errors or deviations in clock timing are called Jitter. 

Although Jitter can be caused by a variety of 

components, it is often a result of defective digital audio 

cables. 


Digital Cables for Multi-Channel 

� ADAT (Alesis Digital Audio Tape) Lightpipe 

� Toslink: fiber-optic 

� Carries 8 channels of digital audio 

� TDIF (Tascam Digital Interface Format) 

� Looks like a 25-pin computer cable, but pins are in different order 

� Carries 8 channels of digital audio in both directions (in/out)

dB SPL Sound Source (with distance) - Brian K. Shepard

Create successful ePaper yourself

Delete template?

Save as template?