Owner's Manual
The
Mobile
Tools
Application
Initial
Menu
Page
Select any menu item
to
access
the
following functions
of
the
Mobile
Tools application:
•
RTA
Real
time
analyzer
•
FFT
Fast
Fourier transform analyzer
• Polarity
Speaker polarity analyzer
•
SPL
Sound Pressure Level
Meter
• DQ61
An
analyzer
for
the
AudioControl
DQ61 car audio system
• Information
Helpful
advice
for
Mobile Tools
including General
information and
Microphone
information
The various
Mobile
Tools audio measurement and display functions are
briefly described
below. For more
information
and details
of
the
uses and
usefulness
of
real-time analyzers,
FFT
analyzers, and
SPL
meters, etc.,
please visit your local library, the web,
or
take a
trip
to
your local sound
guy
p~ny-tail
convention.
RTA
Real
Time
Analyzer
Typical
RTA
Page
This graph shows
the
Sound Pressure Level measured by
the
microphone
across
the
audio frequency band
20Hz
to
20kHz.
In
this example, the
measured response starts
to
decrease at
the
higher frequencies.
Menu
items along the
bottom
allow you
to
(from left
to
right)
Change
the
width
of
the
sample in fractions
of
an
octave
Pause/start the measurement
Save
and recall measurements
Setup
the
internal signal generator
to
play audio through
your
sound
system
Setup
the
display, such
as
SPL
range, frequency range
• Choose
the
measurement decay rate
Experiment
with
any
of
the
RTA
controls until you are at one
with
them.
------------------------------------------------7--------------------------------------------------
FFT
Fast
Fourier Transform
Analyzer
Typical
FFT
Graph
This
FFT
graph shows
the
Sound Pressure Level across the audio fre-
quency band
20Hz
to
20kHz, after the
Fast
Fourier Transform
has
been
applied mathematically
to
the microphone measurements.
FFT
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250
500
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FFT
spectrum analysis gives early clues
to
any audio distortion
in
the
system. This distortion may occur through speakers being overloaded,
amplifiers
going
into
clipping, mixer signals overloading, and
so
on.
If
a pure sine wave was playing at a certain frequency, then the micro-
phone
would measure this, and
the
FFT
display would show a peak at
the
fundamental frequency. If however, this pure sinewave was overloading
the
power
amplifiers and causing distortion, then the
FFT
graph would
display
the fundamental frequency peak,
as
well
as
other
(naughtier}
peaks at higher harmonic frequencies.
Note:
If
the
Fast
Fourier Transform seems
to
be
running slowly,
ask
the
band
to
pep
it
up a bit.
Menu items
along
the
bottom
allow you
to
(from left
to
right)
Change the graph smoothing in fractions
of
an
octave
Pause/start the measurement
Save
and recall measurements
Setup the internal signal generator
to
play audio through your sound
system
Setup
the
display, such
as
SPL
range, frequency range
Choose the measurement decay rate
Experiment
with
any
of
the
FFT
controls until you are also at one
with
them.
If
this was Scouts, you
would
then proudly earn
your
FFT
badge.
Polarity
This menu allows you
to
analyze
the
speakers in your system and deter-
mine which
of
them
may
be
wired
out
of
phase compared
to
the others.
For
example, the positive and negative speaker cords may
be
swapped
on one speaker, giving rise
to
an
audio cancellation, most noticeable at
the
lower
frequencies.
SPL
sound
Pressure
Level
Meter
This display shows
the
measured Sound Pressure Level. This
is
very useful
in setting up a system and determining
for
example,
that
the
SPL
does
not
reach unsafe levels
that
may cause hearing damage.
Menu
items allow you to:
Change the measurement weighting (unweighted,
A,
or
C-weighting)
Reset the measurement
Save
and recall measurements
Vary
the
measurement
from
fast, slow, impulse, peak
Set
the
input
Set
the
output
------------------------------------------------8 --------------------------------------------------