Mackie glossary Manual Do Utilizador

Página de 18
 
5
 
DAW
 
Digital Audio Workstation is a dedicated 
recording/editing software application and 
hardware system, used for hard disk (non-lin-
ear) random access recording and playback. 
Many DAWs are used with personal computers 
using Windows® or Macintosh® operating 
systems, though some use their own proprietary 
computers.
 
dB
 
See decibel.
 
dBA
 
Sound Pressure Level (SPL) measured with an 
"A" weighting filter.
 
dBm
 
A unit of measurement of power in an electrical 
circuit, expressed in decibels referenced to 1 
milliwatt. The “m” in dBm stands for “milli-
watt.” In a circuit with an impedance of 600 
ohms, this reference (0 dBm) corresponds to a 
signal voltage of 0.775 VRMS (because 0.775 V 
across 600 ohms equals 1 mw).
 
dBu
 
A unit of measurement of audio signal voltage 
in an electrical circuit, expressed in decibels ref-
erenced to 0.775 VRMS into any impedance. 
Commonly used to describe signal levels within 
a modern audio system. Nobody is really sure if 
“u” stands for anything. 
 
dBv
 
A unit of measurement equal to the dBu no 
longer in use in the US, but sometimes still in 
Great Britain. It was too easy to confuse a dBv 
with a dBV, to which it is not equivalent.
 
dBV
 
A unit of measurement of audio signal voltage 
in an electrical circuit, expressed in decibels ref-
erenced to 1 VRMS across any impedance. 
Commonly used to describe signal levels in 
consumer equipment. To convert dBV to dBu, 
add 2.2 dB.
 
decibel (dB)
 
The dB is a ratio of quantities measured in sim-
ilar terms using a logarithmic scale. Many audio 
system parameters measure over such a large 
range of values that the dB is used to simplify 
the numbers. A ratio of 1000:1=60 dB. Since 
dB is a unitless quantity, it doesn’t matter if it’s 
volts or dollars. (just try asking the chief engi-
neer for a 3 dB raise) When one of the terms in 
the ratio is an agreed upon standard value such 
as 1.23 V, 1 V or 1 mw, the ratio becomes an 
absolute value, i.e., +4 dBu, -10 dBV or 0 dBm.
 
delay
 
In sound work, delay usually refers to an elec-
tronic circuit or effects unit whose purpose it is 
to delay the audio signal for some short period 
of time. Delay can refer to one short repeat, a 
series of repeats or the complex interactions of 
delay used in chorusing or reverb. When 
delayed signals are mixed back with the original 
sound, a great number of audio effects can be 
generated, including phasing and flanging, dou-
bling, Haas precedence-effect panning, slap or 
slapback, echo, regenerative echo, chorusing 
and hall-like reverberation. Signal time delay is 
central to many audio effects units.
 
detent
 
A point of slight physical resistance (a click-
stop) in the travel of a knob or slide control. 
Most knobs on Mackie mixers are detented to 
indicate their unity gain or centered position. 
It’s handy in the dark.
 
diffraction
 
The bending of sound waves around an obsta-
cle (Huygens Principle). The longer the wave-
length in comparison to the obstacle, the more 
the wave will diffract around it.