PT-9A Polarity Test Instrument
The PT-9A is an essential tool for mobile electronics installation. With proper use, it should aid you in achieving optimum
performance from any multi-speaker mobile audio system. Please read the user manual carefully and follow the instruc
-
tions provided.
What is the Overall Goal?
The goal of any audio system with multiple speakers is to reproduce sound energy so that the phase between all speakers
is complimentary (rather than destructive). This means all speakers in the system need to be working together. The PT-9A
allows the install technician to verify the absolute phase of each speaker in the system, both individually and as a group
using a combination of internally generated pulses and pulses from the test CD.
Simple
GREEN
or
RED
light pulses on the front of the instrument indicate the overall condition of the speaker(s) being
evaluated in real time while installed in their final position(s) in the vehicle. It can’t get much more accurate than that!
About the Internal Pulse Generator
The PT-9A features an internal pulse generator output that simultaneously processes speaker pulses through the built-in
microphone located on the front of the instrument. This allows the unit to be entirely self contained. The internal generator
provides evenly spaced, positive (pressure) pulses to both the line level jack and speaker level outputs for the duration of
time the unit is on. The
LINE LEVEL
signal is sufficient to drive signal processor and amplifier inputs. The
SPEAKER LEVEL
signal
is sufficient to drive a speaker directly. To use the internal pulse generator, be sure the signal switch is in the
LINE
position.
Alternatively, the PT-9A can use only the built-in microphone to “hear” pulses generated by an external source, such as the
test CD provided. The test CD uses a sequence of 3 positive pulses followed by one negative pulse. Whenever the CD plays
the pulse track (Track 3), the speakers in the system will follow this pulsing sequence. To use only the built in microphone
and pulses from an external source, be sure the signal switch is in the
CD
position.
LINE OUT
SPEAKER
- +
PT-9A
PO
POLARITY -
LOW BATTERY
CD
LINE
SIGNAL
ON
OFF
POWER
Built-in Microphone (Front of Instrument)
Polarity Indicators
Green = Positive (Pressure)
Red = Negative (Vacuum)
Signal Switch
Power Switch
Low Battery Indicator
(Illuminates Yellow when
9.6v battery requires
replacement)
Line Level Pulse Generator
(Active when the Signal Switch
is in the LINE position)
Speaker Level Pulse Generator
(Active when the Signal Switch is
in the LINE position)
Front Panel Layout
