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| Frequency = cycles per second |
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| A musical term for frequency or cycles/second |
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| vehicle for sound transmission: compression is an increase over the norm in pressure; rarefaction is a decrease below the normal pressure |
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| complex pattern of nodes (wave crests doubled) and anti-nodes (wave troughs doubled) brought about by acoustical laws of wave reflection, wave absorption, wave refraction and wave diffusion |
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| derived from Periodic Motion also known as “Simple Harmonic Motion” Sine wave=few, if any discernable harmonics: |
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| Wave Length(expressed in feet) |
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| speed of sound in air (1127 ft/sec) divided by Frequency(cycles/sec) |
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| The Time relationship created when sound arrives at your ears: the sine of X expressed in degrees from 0 to 360: Phase is responsible for localization in Binaural hearing |
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| A generally undesirable recording phenomenon, when two or more mics are employed to pickup the same signal, but due to the placement of the mics, the same signal arrives out of phase/time, canceling out selected harmonics and frequency content creating a hollow or non-sonorous element of the original sound; |
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| (ADSR) Attack, Decay, Sustain, Release (note –off) or silence |
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| Musical term describing the character of a sound which is determined by the Harmonic |
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| Musical term; a doubling of frequency or a frequency Ratio of 2:1/ |
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| Sensitivity to Frequency or bandwidth |
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| Sound Pressure Level measured subjectively in decibels/SPL from soft to loud |
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| Addition or subtraction of gain (amplitude) for small selected bands of frequencies |
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| Weaken or rarefy a signal, normally accomplished by increasing impedance |
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| Transmission of power from one form of energy to another |
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| Logarithm or ratio type of Unit for measuring the volume/amplitude/pressure of a |
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| Sudden and abrupt, normally undesirable signal or voltage/ trigger voltage/spike |
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| 1127ft/sec in air @59F; 283, 280 ft/sec in water; 990,000 ft/sec in steel; |
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| Speed of sound (1127 ft./sec.) divided by Frequency (cycles/sec.) = length in feet |
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| Portion of speech that requires high frequency bandwidth; hiss |
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Definition
| All frequencies, at equal levels, averaged over time / Aperiodic Motion |
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Definition
| white noise that has been modified thru a pinking filter providing a 3db/octave roll-off |
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| States that human hearing does not exhibit flat frequency response; Scientists Fletcher-Munson and Robinson-Dodson proved that human hearing is not linear across the range of hearing from 20 Hertz to 20,000 Hertz |
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| In order to recover all Fourier components of a periodic waveform, it is necessary to sample more than twice as fast as the highest waveform frequency. The Nyquist frequency, also called the Nyquist limit, is the highest frequency that can be coded at a given sampling rate in order to be able to fully reconstruct the signal. |
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| An increase in low frequency response when a microphone is very close to the sound source |
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| “0 dB SPL” of a young and undamaged ear |
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| Between 120 and 130 (phons or dB SPL) measured at 1Khz |
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| Digital Signal Processing |
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Definition
| Equalization, Gating, Compression/limiting, Normalize, Filtering |
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| Reverb, Delay, Chorusing, Flanging, Phasing, Doppler |
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Definition
| The intensity of the sound (dB SPL) varies with the distance: For each doubling of distance(in meters) from the source, the SPL with drop by 6 dB |
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Definition
| Impedance (measured in ohms) Note: Adding resistance/impedance attenuates a signal |
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Definition
| A basic phenomenon of electricity; the basis of the electrical transformer where a voltage is passed thru a coil which is interleaved with another coil: Inductance occurs as electrons gravitate toward the “empty wire” or lowest energy state, thus providing isolation from the original source: Inductance via a transformer also provides changes in impedance or resistance depending on the length and number of wrappings of the copper wire: for instance from Hi Z (10K ohms RCA Phono or 1/4 connector types) to Low Z (600ohms XLR, TRS connectors) or vise versa |
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Definition
| The ability to retain or store an electrical charge (measured in farads) |
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| A Form of interference caused by presence of several sounds (with similar Freq content) |
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| Amplitude Modulation (AM); Frequency Modulation (FM); Ring Modulation |
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Definition
| Patterns of radiation in the case of a speaker, or patterns of sensitivity, in the case of a mic: Omnidirectional, Uni-Directional, Cardiod, Hyper-cardiod, Super Cardiod, Bi-directional, and Ellipsoidal to name a few |
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Definition
| Basic, high impedance, signal inducing transducer: bi-directional; use as a pickup, responds to transients; use as a signal emitter as in fire alarms. 126 dB SPL fire code spec. |
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Definition
| older microphone elements used in early telephone technology and phonograph |
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Definition
| Uses inductance as a vehicle to pickup waves of compression/rarefaction |
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Term
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Definition
| Uses capacitance to bias the backplate/diaphragm producing wide range and high freq sensitivity : Power/phantom power is necessary; dual diaphragm = Bidirectional polar pattern |
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Term
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Definition
| A light, thin, corrugated piece of metal foil is used to produce a warm, rich and full freq response; does not normally like phantom power |
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Term
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Definition
| While both microphones are considered boundary or surface-mounted microphones, they are quite different in application and use. The Pressure Zone Microphone (PZM) has an omnidirectional capsule that "looks down" at the boundary, while the Phase Coherent Cardioid (PCC) microphone has a supercardioid capsule that "looks across" the boundary. |
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Term
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Definition
| Called Phantom because it is unseen and uses the mic cable to send 9 to 48 volts DC up to the condenser mic; this voltage polarizes the backplate/gold diaphragm providing electrical bias. In professional microphones, a provision is made to supply this voltage directly through the microphone cable. This procedure is called phantom powering, and the most common phantom supply voltage available in mixing consoles is 48 VDC, although other supplies of between 18-24 VDC are widely used. How does it work? In a balanced microphone cable are two inner wires surrounded by a shield. It is on these two signal lines that the polarizing voltage is placed, with the same regulated positive voltage on each line. With the positive voltage on the two inner wires, the shield wire is used as the negative return to ground. The audio signal uses the same cable on its way to the mixer, and is not affected by the phantom DC voltage since the signal is AC. |
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Term
| Inline Matching Transformer |
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Definition
| A transformer that changes impedance from hi to low Z via: inductance also provides electrical isolation; sometimes called an isolation transformer |
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Term
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Definition
| Often called a DI box, it allows for a parallel hi Z (unbalanced)input/output while outputs only balanced low Z signal (XLR); an audio (pin 1) ground lift is provided and often can input speaker (8 Ohms) or instrument level (2k-7K Ohms) |
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Term
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Definition
| A noise canceling method of signal transmission employing XLR or Tip-Ring-Sleeve (TRS) connector using three conductor wiring, shield or ground pin 1: program signal pin2: inverted polarity pin3; (XLR- X refers to “trans” or “across” - the LR refers to low(L) and high(R) portions of the phase of the signal. The program signal is first divided into its two major phase components, in-phase and out of phase 0 degrees and 180 degrees; When the signal is re-combined, the noise induced (in and out of phase) is cancelled, leaving only the original program signal. An XLR cable can extend hundreds of feet in length before noticeable signal deterioration. |
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Term
| Professional Mic/Line Level Signal |
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Definition
| A balanced, low impedance 1.23 volts @ 600 ohms Signal. A volt-ohm meter will indicate = +4dB Vu |
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Term
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Definition
| two conductor wiring RCA phono or Tip-Sleeve (TS) connectivity: program(+) and ground shield(-); can only extend about 30-40 feet before signal deterioration |
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Term
| Consumer Line Level Signal |
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Definition
| An unbalanced, high impedance signal employing RCA phono or Tip-Sleeve (TS) connectivity -10dBVu (volt/ohms as in a VU meter) .77 volts @ 10K ohms |
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Term
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Definition
| (on a mic preamplifier) sometimes referred to as “gain = an Attenuator which adds resistance or impedance to cut down signal strength |
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Term
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Definition
-Professional Mic Line Level
-Consumer Line Level
-Speaker |
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Term
| Profesional Mic Line Level(+4dBu): |
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Definition
3 Wire Conductor
Balanced
1.23 Volts
600 ohms
XLR/TRS(Tip Ring Sleeve)
200-300 feet |
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Term
| Consuer Line Level(-10dbU): |
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Definition
.77 volts
10,000 ohms of impedance
RCA Phono, 1/4" Tip Sleeve
Two Wire Conductors
Unbalanced 20-3 feet |
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Term
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Definition
| inherently has a 3dB rise of energy per octave(+3dB/Octave) |
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