Atmospheric Pressure
The force exerted against an object by the weight of the air above it to the top of the Earth’s atmosphere.
Cycles per second
The number of occurrences of a repeating event per unit of time (measured in hertz)
The distance travelled to complete one cycle of a wavelength
The magnitude of change in the oscillation of a sound wave (how high and low the wave goes.) This translated to how loud we hear the sound.
The comparison of where in a wave cycle two sine waves of the same frequence are at the same point in time. It is measured in 360 degrees.
Specular Reflection
Mirror like reflection. The angle that the sound wave first strikes the surface is the same angle with which it reflects back.
The breaking up of sound by reflection back in many directions
The ability of sound to move around physical barriers and through small opening in barriers with little to no effect on the wave energy
The lowest frequency in a complex tone
Any sine waves that make up a complex tone
Partials that are whole integer multiples of the fundamental
Acoustic Envelope
The amplitude change over time of a complex sound. Broken down into 3 parts– attack, internal dynamics, decay
Any device that converts one form of energy to another
A ratio measured against a constant reference point– in sound, the reference could be voltage, SPL, of full-scale digital clipping for example.
Sound Pressure Level. The pressure of sound vibration measured at a specific distance.
Threshold of Hearing
The quietest sound a human could hear
Threshold of Pain
The point at which sound pressure causes pain in the human hearing mechanism
Reverberation TIme (RT)
The time it takes for the reverberation to decrease by 60 dB from its original level
Transmission Loss (TL)
THe reduction of SPL of a sound source as it passes through a physical barrier.
Electrical Insulators
Materials that can’t conduct electricity very well
Electrical Conductors
Materials that conduct electricity very well
The difference in charge (electrons) between two points. The greater the difference, the more the charge wants to move (more potential energy).
How well charged particles (electrons) can move through a given material.
A measurement of total opposition to the flow of current in a circuit
Electromagnetic Induction
A changing magnetic field will induce a current in a circuit.
Electromagnetic Interference
EMI- electromagnetic induction that occurs accidentally or creates a current that we don’t want (or corrupts the signal that we do want)
Dynamic Range
The difference between the noise floor and the maximum volume before the distortion of the signal is considered too much. The total potential useable range.
Signal-to-Noise (SNR)-
This is an active measurement of how much difference there is between a signal as it is moving through an amp and the noise floor. The actual range as it is happening.
Any device that changes (usually increases) the amplitude of a signal. An amplifier circuit is usually created using one of the 3 following components: tubes, transistors, op-amps
Composed of two piece and is the language used to represent digital data of any kind.
Fourier Transform
Every complex sound is made up of a bunch of sine waves (single frequencies). ANY complex sound can be broken down into these individual frequencies and then reconstructed.
Nyquist-Shannon Sampling Theorem
If you know the highest frequency present in a complex sound, as long as you have any two evenly spaced samples charted along that wave, you can reconstruct the complex wave perfectly.
The process of mapping a large set of input values to a smaller set. In digital audio, this is the technique used to represent dynamic range.
Sampling rate
How many ‘snapshots’ are taken of an analog signal over time. Ex: (44.1khz (CD), 48.kHz (DVD and vid)…)
Bit Depth
a Measurement of dynamic range in digital audio where one bit equals roughly 6db increments. Ex: 16bit (CD), 24bit (DVD Blu Ray), 32bit (used for extra headroom when changing volume digitally)