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Glossary and Terms N Thru S
N
Nano - A
prefix meaning one-billionth.
Nano-Webers
Per Meter - The standard unit in measuring the amount of
magnetic energy. Near Field -
The area up to one foot from the sound source. Negative
Feedback - A portion of the output signal that is feed
to the input (of an amplifier), out of phase. Something we just
don't ever get here at www.oregondv.com (Brass
& Granite Audio). Neodymium - A
very strong rare earth magnet used in speaker motors magnets that
allows high sensitivity performance from very small drivers. Noise Filter
- A filter used which passes only signals with the intended audio
frequencies thus eliminating noise signals at other
frequencies.
Noise Floor -
The level of the noise, in dB, below the signal.
Noise Gate
- A gate used to turn off an audio channel when noise but not signal
is present.
Noise
Reduction - Any device to remove noise in a device or
system.
Non-Linear
- The condition of obtaining a change at the output of the device
which is not proportional to the change occurring at the input,
causing distortion.
Normals -
Switches on the patch jacks that connect certain jacks together
until a patch cord is inserted.
Normalizing
Jacks - Switches on the patch jacks that connect certain
jacks together until a patch cord is inserted.
Notch - A
narrow band of audio frequencies.
Notch Filter
- A device that rejects signals that have frequencies within
a narrow band of audio frequencies and passes all other
signals.
Null - A point in
any electronic system where two out-of-phase signals cancel each
other In speaker acoustics, a null is a point in space where a
speakers multiple drivers outputs overlap at crossover
frequencies, but are different enough in phase to decrease the
overall sound level. At the center of nulls, signals interfere
strongly enough to entirely cancel, producing a sound level of 0 db.
The opposite effect occurs in a lobe (see above).
Nyquest
Frequency - The highest frequency that can be recorded
and reproduced properly by a particular sampling rate (a frequency
that is one-half the sampling rate).
O
Ohm's Law - the
scientific law, in electrical matters, that says that the power in a
closed electric or electronic system is a constant relationship
between voltage, amperage and resistance such that V (Voltage)
= I (Amperage) multiplied by R (Resistance). Given any two of
these elements, the third element can be derived by simple
multiplication or division. For example, if a circuit has 28 V
of voltage running through it, and 8 ohms of resistance opposing the
flow, we can calculate the current for that circuit:
28=I multiplied by 8; I=28/8; 28 divided by 8 =3.5
Amperes. So for a circuit carrying 28 volts and offering 8
ohms of resistance, 3.5 amps of current will flow. We can use
this same law to calculate voltage knowing only amperage and
resistance, or resistance knowing only voltage and amperage.
Omni- - A
prefix meaning All.
Omni-Directional
- In speakers, sending out evenly in all directions.
Open -
Short for the term Open Circuit.
Open Circuit
- 1) Having a break in a conductor or, for another reason,
not having a complete path for electrons to flow. 2) Said of an
amplifier, having nothing feeding the input.
Out Of Phase - 1) Being
similar to another signal in amplitude, frequency and wave shape but
being offset in time by part of a cycle. 2) 180 degrees out of phase
or having opposite polarity.
Output -
1) The jack or physical location of where a device sends out a
signal. 2) The signal put out by a device.
Output
Impedance - The opposition to current flow by the output
circuits of an amplifier (or other device).
Output Level -
The signal level at the output of a device.
P
Panpot (Pan
Pot) - An electrical device that distributes one audio
signal to two (or more) channels or speakers.
Parallel
- 1) A circuit interconnection in that the source feeds
several branch circuit components and interruption of current flow
in one component does not stop current flow in another. 2) A method
of sending data where each digit of a digital word is sent at the
same time over separate wires/connections.
Parallel
Jacks - Several jacks that are wired so that each
connection is wired to the corresponding connection of other
jacks.
Parallel Port
- A jack that sends out or receives digital data where
several bits are being sent/received at the same time though
different pins.
Parameter -
Each adjustment that is possible to change in a device.
Parametric EQ
- An equalizer in which all of the parameters of equalization can be
adjusted to any amount including: a) center frequency; b) the amount
of boost or cut in gain; and c) the bandwidth.
Pass Band
- The frequency range of signals that will be passed, not reduced,
by a filter.
Passive
Device - A piece of signal processing gear or other
device that does not use an amplifier as part of its design.
Patch - 1)
To route or reroute the signal in an audio system (such as a
console) by using short cables with plugs inserted into jacks. 2)The
routing or rerouting of the signal accomplished by #1.
Patch Bay -
A Series of jacks with connections for most of the inputs and
outputs of the console, console sections, tape machines and other
pieces of equipment.
Patch Cord
- A cable with two plugs on it to interconnect two patch jacks in
the patch bay.
Patch Field
- A series of jacks which has connections for most of the inputs and
outputs of the console, console sections, tape machines and other
pieces of equipment.
Patch Panel
- A series of jacks which has connections for most of the inputs and
outputs of the console, console sections, tape machines and other
pieces of equipment.
Patch Point
- One jack in a patch bay.
Path -
Short for Signal Path, the way in which current does or may travel
in a circuit or through a device.
Peak - 1)
The highest point in the audio waveform. 2) Short for Peak Detecting
(responding to the peak) or Peak Indicating (showing the peak). 3)
Having a frequency response that would draw something similar to a
mountain peak on a frequency response graph.
Peak
Detecting - Recognizing and responding to peak values of
a waveform rather than average values.
Peak
Indicating Meter - A meter which reads the absolute peak
level of the waveform.
Peak Level -
A term with the same meaning as Peak Value (the maximum positive or
negative instantaneous value of a waveform).
Peak
Responding - Recognizing and responding to (or
indicating) the peak value rather than the average or effective
value.
Peak Response
- 1) A term with the same meaning as Peak 2) Raising or lowering of
the amplitude of signals at the center frequency more than signals
at any other frequency.
Peak Value
- The maximum positive or negative instantaneous value of a
waveform.
Peaking
Filter - An EQ circuit which has a peak response
(raising or lowering of the amplitude of signals at the center
frequency more than signals at any other frequency).
Peak-to-Peak
Value - The difference in amplitude between positive and
negative peaks. Equal to twice the peak value for a sine wave.
Phase - A
measurement (expressed in degrees) of the time difference between
two similar waveforms.
Phase
Addition - The energy of one waveform increasing the
energy of another waveform because the two waveforms have similar
phase relationships.
Phase
Cancellation - The energy of one waveform decreasing the
energy of another waveform because of phase relationships at or
close to 180 degrees.
Phase
Distortion - A change in the sound because of a phase
shift in the signal.
Phase Shift
- A delay introduced into an audio signal measured in degrees
delayed.
Phon – 1)
A unit of equal loudness for all audio frequencies. 2) The phon is
numerically equal to dBspl at 1000 Hz but varies at other
frequencies according to ear sensitivity to frequency.
Pin Plug –
1) A term with the same meaning as RCA Plug. 2) The common audio
connector found on most stereo systems with a center pin as one
connection and an outer shell as the second connection. www.oregondv.com
Plug
- A connector, usually on a cable, that mates with a jack.
Polypropylene - a
versatile form of polymer used for speaker cones because of its low
mass and high damping.
Potentiometer
- A device that outputs pan of the input voltage according to the
position of the control's knob.
Power- 1)
The measurement of the ability of an electrical current to produce
light, produce heat or do other work. 2) A similar measurement of
another energy form to do work. 3) The name of the switch which
turns on a device.
Power
Amplifier - A device that takes a line level signal and
amplifies it to be able to drive a speaker.
Power Supply
- An electrical circuit which supplies voltage and current
for devices to operate.
Pre-Amp
- A low-noise amplifier designed to take a low-level signal and
bring it up to normal line level.
Pre/Post
Switch - A switch on the input module, which determines
whether the echo send control comes before or after the main channel
fader.
Pre Emphasis
- A boosting of high frequencies during the recording process to
keep the signal above the noise at high frequencies.
Pre Fader
- A placement of a send control (or other control) before the main
channel fader.
Pre Fader
Listen - A solo circuit that allows a channel signal to
be heard (and often metered) before the channel fader.
Presence
Frequencies - The range of audio frequencies between 4
kHz and 6 kHz that often, when boosted, increases the sense of
presence, especially on voices.
Preset -
1) A program of a sound done at the factory by the manufacturer. 2)
A set of factory set parameters to give one effect on a signal
processing device.
Protocol
- A system of digital data where the positioning of the data, and
what each bit in the data stream signifies, is according to a
standardized format so all devices can properly interpret the
data.
Proximity
Effect - In directional microphones, the boost in the
microphone's output for bass frequencies as the mic is moved closer
to the sound source.
Psychoacoustics
- The study of how things sound to individuals because of mental or
emotional factors.
Puck - Any
circular piece of metal, fiber, rubber, etc., which drives something
from a rotating power source.
Pulse - A
rise and then fall in amplitude, similar to a square wave but
staying up for less time than staying down.
Q
Q
- The sharpness of the peak response in an equalization
circuit.
Quad
(Quadraphonic) - A system of four channel sound where
the channels are designated as left front, left back, right front,
and right back.
Quality
Factor - Quality Factor, (the ratio of reactance to
resistance in a coil) which affects Q.
Quantize
- The conversion of the values of an analog wave or random
occurrence into steps.
Quantization
- A quantizing (see above).
R
Rack Mount -
To mount in an equipment rack.
Rack Space
- A standardized size of the front mounting plate in outboard gear
equal to approximately 1 3/4" tall by 19" wide.
Radio
Frequencies - Frequencies higher than 20,000 Hz (usually
above 100 kHz).
Ramp Wave
- A waveform that is similar to a sawtooth waveform but different in
that it starts at zero level and gradually rises to its peak level
and then instantly drops back to zero level to form one cycle.
Rarefaction
- The air particles being spread apart in the formation of a
sound pressure wave.
Rated
Load Impedance - The input impedance (opposition to
current flow by an input of a device) that a piece of equipment is
designed to feed.
RCA Plug
(jack) - The common audio connector found on most stereo
systems.
Reactance
- Opposition to the flow of electrical current which changes with
the frequency of the current.
Reference
Level - 1) A standard value used to describe how much
level is present in dB above or below this reference. 2) A term with
the same meaning as the term Operating Level (the maximum average
level that should not be exceeded in normal operation).
Reference
Tones - A term with the same meaning as the term Test
Tones (a recording of several single-frequency tones at the
beginning of a tape reel at the magnetic reference level that will
be used to record the program).
Regulated
Power Supply - A device to supply power to electronic
equipment whose output voltage will not fluctuate when more
equipment is turned on, or if there is a change in voltage of the
power line.
Relay - An
electric switch, when a control voltage is applied to the device,
two terminals are connected (or disconnected).
Relay Rack -
An older term for the term Equipment Rack, a cabinet with rails (or
free standing rails) that have holes to accept screws at standard
spaces and used to house outboard gear.
Resistance (Ohms, or R)
- the opposition that a material offers to the flow of electricity
in a circuit. As every material (including wire and
connectors) offers some level of resistance, using components of
differing resistance can direct or divert voltage and
amperage. When occurring in a direct current circuit, this
opposition to current flow is referred to as resistance; in an
alternating current circuit, as impedance. Resistance can be
compared to an upward angle in a pipe carrying water.
Resistor
- A device which opposes the flow of electrical current and does so
evenly at all frequencies.
Resonance
- The prolonging of the sound at a certain frequency and the
tendency of something to vibrate at a particular frequency after the
source of energy is removed.
Resonant
- 1) Tending to pass signals of a certain frequency or narrow range
of frequencies more than signals of other frequencies. 2) Physical
properties that tend to reinforce the energy at certain frequencies
of vibration.
Resonant
Frequency - The frequency at which a physical item tends
to vibrate after the source of energy (causing the vibration) is
removed.
Resonate -
1) To vibrate at the resonant frequency. 2) To linger on, as in
reverberation, said of sound in a room or used to describe a
room/area that has reverberation with a long reverb
time.
RF
Interference - The induction
(generation of current by magnetic lines of force cutting a
conductor) of RF signals (usually broadcast by television and radio
stations) into audio lines causing noise, buzz and static.
Ringing -
An undesirable resonance at the cut off frequency of a filter that
has a high rate of cut-off.
Rise Time
- How fast an audio waveform makes a sudden increase to a higher
level.
Roll-Off - The
reduction of signal level as the frequency of the signal moves away
from the cut-off frequency, especially when the cut-off rate is
mild.
Room Sound - The
ambience of a room including the reverberation and background
noise.
Room Tone -
The background noise in a room without people speaking or music
playing.
Root Mean
Square - The effective
average value of an AC waveform, abbreviated: RMS.
Round Sound -
A pleasingly balanced sound (having a pleasing mixture of high
frequency to low-frequency content).
RMS - The
effective average value of an AC waveform.
RMS detecting
- A control circuit that recognizes and responds to the effective
average, the RMS level (see preceding entry) rather than to the peak
level.
Rumble -
A low-frequency noise, especially that caused by earth/floor
vibration or by uneven surfaces in the drive mechanism of a recorder
or playback unit.
S
Sample Rate
- In digital recording, the number of times per second that samples
are taken.
Sampling
Frequency - Same as Sample Rate (the number samples
taken per second).
Satellite - when
used with a larger subwoofer, smaller front left and right main
speakers (either physically smaller or set to "small" in
multi channel speaker setups) are sometimes referred to as
"satellites." In common use, the term can
apply to physically or electronically small rear or surround
speakers as well.
Sawtooth
Waveform - A waveform that jumps from a zero value to a
peak value and then gradually diminishes to a zero value for each
cycle.
Schematic
Diagram (Schematic) - A diagram that shows the signal
paths and electronic components of a device.
Sensitivity - The
ratio of output power to input power in a speaker system, defined as
either as power sensitivity or voltage sensitivity. Power
sensitivity is determined by inputting one watt into a speaker and
measuring what comes out; the ratio is the power sensitivity
rating. The current/voltage relationship depends on the
speakers impedance.
Most manufacturers quote voltage
sensitivity for their speaker products. Voltage sensitivity is the
ratio of output power to input power when 2.83V is applied across
the speaker terminals. The resulting sound output is
measured at a distance of one meter and the result expressed
in decibels (dB).
Shield
- 1) The outer conductive wrapping around an inner wire or
inner wires in a cable. 2)To protect the inner wire or inner wires
in a cable from pick up of energy given off by such things as
florescent lights.
Shielded
Cable - Cable that has a shield around an inner
conductor or inner conductors.
Shortest
Digital Path - The routing of the digital audio signal
so that there is a minimum amount of D/A conversion, A/D conversion
or Sample Rate conversion.
Signal -
1) In audio, an alternating current (or voltage) matching the
waveform of, or being originally obtained from a sound pressure
wave. 2) Also in audio, an alternating current (or voltage) between
20 Hz and 20,000 Hz. 3) A digital audio bit stream.
Signal Flow
- The path that a signal moves through an audio system such as a
console.
Signal to Noise Ratio (SNR or
S/N) - The ratio of maximum signal level to the residual
noise level, or noise floor, of an electronic component.
Usually measured on a logarithmic scale in dB, this also indicates a
components dynamic range.
In room acoustics, SNR is measured
by first establishing the rooms noise floor (background noise from
vents, mechanical equipment and leakage from outside sources) and
then comparing that to the maximum acoustic output of the
rooms speaker system. www.oregondv.com
The ratio will be the signal to noise ratio of the room.
Signal to Quantization Noise Ratio
(SQNR) - A measure of the quality at which analog signals are
converted (ie, quantized) to digital signals, expressed in
decibels. The ratio is approximately equal to 6 times the
number of bits accommodated by the analog to digital converter, or
ADC. For example, the maximum achievable SQNR for
quantizing at 16-bit detail is around 96 dB, which is known as CD
quality. SACD, at the equivalent 20 bits, achieves an SQNR of
120 dB, and DVD-A, at 24 bits, of 144 dB.
Sine Wave
- The waveform that would be obtained from a vibrating
source that was vibrating at just one frequency (making a pure
tone).
Solder -
A soft mixture of metals used to make a bond between two metal
surfaces by melting. In audio work the mixture is usually tin and
lead which is used in permanently connecting wires to terminals.
Soldering
- The action of making connections with solder (a soft
mixture of metals used to make a bond between two metal surfaces by
melting).
Solid State
- In electronics, using transistors and semiconductor devices rather
than tubes.
Sound
Absorption - Same as Acoustical Absorption
(the action or quality of a surface or substance to absorb sound
rather than reflect it).
Sound Blanket
- A thick blanket that can be put on floors or hung to help
prevent sound reflections.
Sound Level
- A shortening of the term Sound Pressure Level (a measure
of the sound pressure created by a sound).
Sound
Level Meter - A device that measures the
sound pressure levels.
Sound Patch
- Full name of the term Patch
Sound Pressure Level (SPL) -
The ratio of the pressure of a sound wave to standard, normative air
pressure level, expressed in decibels, or dB. Everyday sound
pressure level differences can be extreme: a whisper is 20 dB,
normal speech 70 dB, a passing subway train 100 dB, large jet }
{plane, 120 dB. www.oregondv.com
Sound pressure levels are measured upward from the point just below
audibility, that is, right above the standard noise level created by
random thermal currents in a room. Humans perceive a change in
SPL of 10 times as a doubling of loudness; that is, a change in SPL
of 10 dB is perceived as twice as loud, not 10 times as loud.
Sound
Pressure Wave - Alternate compressions (compacting
together) and rarefactions (spreading apart) of air particles moving
away from something that is vibrating between 20 and 20,000 times a
second or a similar occurrence in another substance (such as water).
Sound Quality
- A microphone characteristic of how well the diaphragm movement
matches the pressure changes of a sound pressure wave reaching it,
especially sudden changes.
Sound Source
- Something that vibrates between 20 times a second and
20,000 times a second and therefore makes a sound pressure
wave.
Sound Wave
- Short for Sound Pressure Wave (a wave of pressure changes
moving away from something that is vibrating between 20 times a
second and 20,000 times a second).
Source -
Input mode on a tape machine where the meters and the output of the
machine's electronics will be the signal arriving at the input
connector.
Speaker
- A device that changes electrical signals to sound which
can be heard; a transducer changing the electrical audio signal into
a sound pressure wave.
Speed of
Sound - The wave velocity (the time it takes for one
point of the waveform to travel a certain distance) of a sound
pressure wave, 1130 feet per second at 70 degrees Fahrenheit.
Spin Control
- A British term for Feedback Control (a control that
determines the amount of delayed signal sent back to the input of a
delay line, used in repeat echo effects).
SPL - An
abbreviation of Sound Pressure Level, referring to a pressure of
.0002 microbar, considered to be the Threshold of Hearing (lowest
level where people begin hearing sound).
Stereo -
A recording or reproduction of at least two channels where
positioning of instrument sounds left to right can be perceived.
Stereo Image
- The perception of the different sound sources being far left, far
right or any place in between.
Stylus -
The needle part of the phonograph cartridge that is in contact with
the grooves of the disc.
Subcode
- Control information bits that are recorded along with digital
audio and can be used for control of the playback deck (functions as
program number, start ID's, skip ID's etc.).
Subframe
- A unit smaller than one frame in SMPTE time code.
Subwoofer - A speaker
driver designed to operate over the low bass portion of the audio
range, generally considered to be below 50 Hz. Also, a system
consisting of such a woofer and its enclosure which are physically
separate from the main loudspeakers. Subwoofers designs are
usually either ported (ie, have open bass vents), which offer higher
output but less accuracy, or sealed, which offer lower output but
more accurate musical reproduction.
Two-way, three-way, four-way
speakers - different types of speaker designs intended for
varying purposes.
Two-way speaker - a
speaker system with two individual drivers covering the audio
frequency spectrum in two bands. Two-way systems represent a
good compromise between size, cost, complexity and bass
extension. The function as a general purpose design, can
serve well in wide variety of roles, but for the most part lack
the ability to produce deep bass at higher output levels.
Three way speaker - a
speaker system with three individual drivers to cover the audio
frequency spectrum. Three-way systems generally have more
bass extension and more dynamic range; ie, will play louder, than
two-way systems, but are more complex to design and build and are
usually larger and more expensive.
Four-way speaker - a
speaker system with four individual drivers to cover the audio
frequency spectrum. Larger and more complex than the others
above, they usually offer yet greater bass extension and dynamic
range. Four-way systems are generally the most complex
systems built using conventional passive crossovers. Restricting
the bandwidth of each driver by using four drivers as
opposed to two or three to cover the entire audible frequency
spectrum, gives the designer the opportunity to extract the
maximum performance from each driver.
Sum
- A signal that is the mix of the two stereo channels at equal level
and in phase.
Sum
and Difference Signals - When the two stereo channels
are mixed at equal levels and in phase, the sum signal is
created.
Surround
Sound - A technique of recording and
playback of sound used in film where the sound has a front to back
quality as well as side to side perspective.
Brass
& Granite Audio
www.Oregondv.com
Salem, OR 97303
See our our other sites:
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www.speakerfeet.net
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