FBT FORMULA 122E - Manual (Page 27)

25
TECHNICAL GLOSSARY
ENGLISH
BAND PASS (band pass filter)
BALANCED, Line
BUS
CMRR
ENVIRONMENT EQUALIZER
HIGH PASS FILTER
IMPEDANCE
GROUND
MULTIEFFECT
In a crossover it is a filter that allows the passage of a band or an
interval of frequencies and significantly attenuates or rejects
frequencies out of the same interval.
A cable with two conductors surrounded by a screening, in which
each conductor is found at the same impedance related to the
ground. The conductors are at the same potential related to the
ground but with opposite polarity, the signal flows through both
conductors.
In the audio terminology a Bus is a point of the circuit in which
many signals are incorporated. For example: many electronic
objects have a Ground Bus in which all the ground paths of all the
devices are linked together. In mixers there are Mix Buses, in
which different audio signals are routed simultaneously, and a Aux
Bus, through which the auxiliary-sends of each individual channel
can be conveyed globally to external devices or monitor-sends,
etc. Generally, more Buses has the mixer, more flexible will be its
routing ability.
Common Mode Rejection Ratio. It corresponds to the ability of an
amplifier to annul eventual disturbance signals (for ex.
electromagnetic interferences) present on the balanced inputs. Its
“dB” value expresses the signal attenuation measure on common
mode produced on the balanced input.
Parametric graphic equalizer able to enhance or attenuate the
frequency bands by some slide cursors, which quantity is variable.
The aim of equalizers it to correct the acoustic response defects in
an environment. Usually the way to operate is the following: The
environment equalizer is connected in insert between the mixer
and the power amplifier, a pink noise is sent to the diffusers while a
microphone ( with special linearity characteristics) is connected to
a spectrum analyzer to check which frequencies result penalized
or emphasized from the surrounding environment. At this point the
equalizer has the task to correct these imperfections recreating a
response curve the most linear possible.
A filter that makes the frequencies pass without changing them
beyond a certain frequency and attenuating those under the same
frequency.
Impedance refers to the resistance of a circuit or an AC (alternate
current) device.
Electric reference point for a signal that circulates in a circuit or on
a cable. Generally ground achieves the value of zero volts and is
transported by the audio cables by a metal braid that has also the
function of signal screening, or protection against external
electromagnetic disturbances.
Audio device able to process a digitalized audio signal by
mathematic algorithms of reverberation, echo, chorus, flanger,
gate, etc.
NOISE
FIRST REFLECTIONS
REPLY FREQUENCY
REVERBERATION
UNBALANCED
THD (Total HarmonicDistortion)
It is the quantity of noise generated by a special device or system,
in absence of applied signal, and is measured in decibel. All the
electronic devices generate a particular noise rate, also a simple
piece of cable!
If Noise is minimized, an overall dynamics
increase, cleaner recordings or a truer sound are obtained.
Sound is reflected a number of times before arriving to our ears.
The distance and the frequency with which these reflections occur
depend strongly to the dimensions of the environment in which
they take place.
The frequency reply is the real interval of frequencies that a device
can reproduce, for example from 5Hz to 22kHz. The frequency
reply is the frequency range in relation to the amplitude. In other
words, at 20Hz a certain input signal can produce 100dB in output,
at 1kHz the same signal in input can produce 102dB in output, at
10kHz, 95dB and so on.
Reverberation is the result of a series of audio reflections. The
order and value of each reflection is conditioned by the
environment in which it occurs. There are many factors that
operate inside the same environment, for example the
dimensions of the place where the phenomenon occurs, the
nature of the materials that compose it and the objects that are in
it, the listener position, etc.
Is the condition in which the two branches of a circuit are not equal
and opposed related to the ground, usually because a branch is
maintained to the ground potential. Unbalanced circuits are much
more susceptible to noise problems related to balanced circuits.
For this reason, the unbalanced lines have to be kept the most
possible with a limited length (less than 40cm) to minimize
potential noise problems.
The ratio between the basic frequency power at a device output
related to the overall power of all the harmonics in the frequency
band available at the device output. All the audio devices
introduce a certain distortion to the audio that passes through
them. The most simple form of this distortion is represented by
harmonics added to the output signal. THD represents the sum of
all the harmonics added by an equipment, as percentage of the
signal level that ismeasured.