33
H
U
I R E F E R E N C E G U I D E
GLOSSARY
The following is an admittedly short glos-
sary of audio terms used in this owner’s
manual. The more basic terms can be found in
a variety of places; we’d be foolish to forget to
mention our web site. Go to
www.mackie.com
to find a more thorough audio glossary. Addi-
tionally, we recommend the following books:
The Audio Dictionary
, by Glenn White;
Tech
Terms
, by Peterson & Oppenheimer;
Handbook
for Sound Engineers
, by Glen Ballou; and
Sound
Reinforcement Handbook
, by Gary Davis.
active sensing
MIDI message echoing that occurs between
HUI and the host DAW to confirm that commu-
nication is occuring. The right-hand decimal
point in the Time Code Display blinks once per
second to indicate that MIDI communication is
established.
DAW
See
digital audio workstation
.
DSP
Abbreviation for
digital signal processing
.
DSP can accomplish the same functions found
in analog signal processors, but performs them
mathematically in the digital domain, with more
precision and accuracy than its analog counter-
part. Since DSP is a software-based process,
parameters and processing functions are easily
changed and updated by revising the software,
rather than redesigning the hardware. DSP can
be found in an outboard effects device, such as
a reverb or delay unit, or it can be integrated
into a DAW or digital mixing console.
discrete channel
Used in reference to surround-sound appli-
cations, a discrete channel is separate or
isolated from the stereo pair of channels it is
normally associated with.
digital audio workstation (DAW)
A dedicated recording/editing software (appli-
cation) and hardware system, used for hard
disk (non-linear) random access playback and
recording. Many DAWs are used with personal
computers using Windows
®
95 or Macintosh
®
operating systems, though some use their own
proprietary computers.
effects devices
External signal processors used to add re-
verb, delay, spatial, or psychoacoustic effects
to an audio signal. An effects processor may be
used as an insert processor (serial) on a par-
ticular input or subgroup, or it may be used via
the aux send/return system (parallel). See also
echo, reverb.
FMS
Short for
FreeMIDI System
. FMS allows your
computer to decipher information coming from
the MIDI interface, which is connected to both
your computer and HUI.
gain stage
An amplification point in a signal path,
either within a system or a single device. Over-
all system gain is distributed between the
various gain stages.
linear, non-linear
Linear audio recording and playback is
sound that has been recorded to tape and
played back in the same linear fashion. Non-lin-
ear recording and playback uses audio sound
files that have been “recorded” to the hard
disk of a computer. Though the sound file in-
formation may be stored in a random fashion
on the hard disk, it is played back in the same
linear way it was recorded.
line level
A signal whose level falls between –10dBu
and +30dBu.
MIDI
Acronym for
musical instrument digital inter-
face
. MIDI is the music industry’s standard
serial communication protocol. HUI uses MIDI
to bidirectionally communicate with the DAW
software. (Refer to the DAW controller docu-
mentation for specific MIDI routing and
channel information prior to hookup.)
OMS
Short for
Open Music System
. OMS allows
your computer to decipher information com-
ing from the MIDI interface, which is
connected to both your computer and HUI.
phantom power
A system of providing electrical power for
condenser microphones (and some electronic
pickup devices) from the sound mixer. The sys-
tem is called phantom because the power is
carried on standard microphone audio wiring in
a way that is “invisible” to ordinary dynamic
microphones. Mackie mixers use st48
volt DC power, switchable on or off. Most qual-
ity condenser microphones are designed to use
+48 VDC phantom power. Check the
manufacturer’s recommendations.
Generally, phantom power is safe to use
with non-condenser microphones as well, es-
pecially dynamic microphones. However,
unbalanced microphones, and some electronic
equipment (such as some wireless microphone
receivers), can short out the phantom power and
be severely damaged. Check the manufacturer’s
recommendations and be careful!
GLOSSARY
