Sound & Hearing Flashcards
Control Room
Where majority of engineer’s tools are kept
e.g. console, control surface, outboard gear, power amps, computer systems, multitrack machines, etc1
How is the Control Room built?
To be acoustically isolated from other parts of the studio (tracking rooms), including outside surroundings
What is the Control Room for?
Critical listening
What are the Two Recording Processes?
Real-time & Multitracking
What is Real-time recording?
With 1 or 2 mics, the musicians & artists would be positioned and play all together, recording live on one track - mixing is done at the same time
What is Multi-track recording?
All artists & musicians can be recorded on their own track, either at the same time or separate times, or even both - this allows endless mixing possibilities
What are the steps of pre-production?
- budget
- type of artist
- how many songs
- how many tracks for each song
- what format being recorded to
- how much studio time has been booked
- what is the goal of the project
3 Main steps to Recording
- Recording (tracking, basic tracks)
- Overdubbing - basic tracks are played over headphones and additional tracks are recorded to either fix, add, re-record an entire take
- Mixing (mixdown) - panning, balancing levels, eq, dynamic processing, time-based effects, etc
What is the definition of engineering?
The application of scientific & mathematical principles to achieve an end result
Transducer
Any device that changes one form of energy into another CORRESPONDING form of energy
Examples of Transducer
Microphones, speakers, guitar pick-ups, OUR EARS
3 Electrical levels & their measurements
- Mic level - millivolts
- Line level - 1.23 volts
- Speaker level - 1-50 volts
Subjective sound v. Objective sound
Subjective sound implies that a brain is required for sound
- Objective sound asserts that just because a brain may not be present, sound waves were still made, therefore, there is sound
Subjective sound
Brain’s perception & interpretation of vibration of a physical stimulus causing sound pressure waves to propagate through air
Objective sound
Repetitive vibrations of a physical object will produce variations in barometric/atmospheric pressure, aka sound pressure waves
What causes sound pressure waves?
Compression and rarefaction
Compression
Greater than normal atmospheric pressure
Rarefaction
Less than normal atmospheric pressure
List the 7 waveform characteristics
- Wavelength
- Amplitude
- Velocity
- Envelope
- Frequency
- Phase
- Harmonic Content
What direction do low frequencies travel in?
Omnidirectional
What direction do high frequencies travel in?
Unidirectional
Wavelength
The actual physical distance between the beginning and end of a cycle
Complex
Waves that are not necessarily symmetrical and don’t necessarily repeat
Waveform
A graphic representation of a signal’s sound pressure level or voltage level over time
Phase Shift
The difference in time between two waveforms
Amplitude
The distance above or below the centerline of a waveform
Producer
The person who helps the artist and/or record label create the best possible recorded performance and final product, and is also in charge of the entire session
Propagation
The process of sound pressure waves “travelling” through the air
Phase
A time relationship between two or more waveforms
Engineer
This person’s job is to interpret and capture the sonic and creative vision of the producer, artist, and record label through a recording and/or mix
Decibel (dB)
The unit of measurement for sound pressure level (SPL), voltage level, etc.
Fundamental
The note being played
Assistant Engineer
This person’s job is to run the tape machine, Pro Tools, setup and tear down session, document the session, and make sure the session runs smoothly
Peak-to-peak value
Distance from max positive value to max negative value
Peak-Amplitude value
Distance from centerline to max positive, or centerline to max negative
RMS (root-mean-square)
Average of all peak-amp values
Frequency
The measurement of the number of cycles that occur in one second of time/ cycles per second; unit is Hz
Variations in atmospheric pressure
Sound pressure waves
Sine wave
Simple wave; pure tone
Omnidirectional frequencies
Low frequencies
Unidirectional frequencies
High frequencies
Average range of human hearing
20Hz - 20kHz
Range of frequencies humans hear best
1kHz - 4kHz
Formula for Wavelength
W=Velocity / Frequency
Wavelength is measured in __________
Feet per cycle
What is the velocity of a sound wave at room temperature (70°F)?
1130 feet per second
1.1 feet per second
Velocity increases by this much for each degree increase, or decreases by this much for each degree decrease
Amplify
Increase in amplitude
Attenuate
Decrease in amplitude
Cycle
The completion of a wave 360°
Amplitude measurement
Decibels (dB)
Period
The time it takes to complete one cycle
The absolute positive and negative values in a wave form
Polarity
Envelope
The attack, decay, sustain, and release of a waveform
Fundamental
The frequency of the note being played
Harmonics
Whole-number multiples of the fundamental
When the frequency is doubled, that harmonic is called:
An octave
Sound reflects off a surface boundary at an angle _____ & ______ to its original angle of incidence
Equal and opposite
Diffraction
Sound pressure wave’s ability to “bend” around an object
Floating scale (dB)
Designed to measure one value against another
The best dB SPL for listening?
85dBSPL
Masking
When loud sounds cover up softer sounds, so we can’t hear them
Bell Labs engineers who established the Equal Loudness Contours of the human ear
Fletcher and Munson
How would you find the 3rd harmonic of 250Hz?
Multiply 750Hz by 3