Smart SYSTEM 2000 Instruction Manual

Instructions for System 2000 Polarity Chec ker

with Auto-Off Circuitry

Description: The Polarity Checker is a small hand-held

audio testing tool. It is powered by a 9-volt battery and
designed to determine the direction of cone movement
of a dynamic loudspeaker. The device features an inter­nal microphone, a red LED, a green LED and a push-on
switch. A very low current circuit automatically turns
the Polarity Checker off after approximately five min­utes of non-use.

Specialized Polarity pulses are provided on a test CD
that accompanies this device. The recorded pulses and
the hand-held detector feature a unique method of
self-authentication whereby the system actually checks
itself to insure proper readings. No other polarity checker
has this feature. This means that the Polarity Checker is
highly accurate, extremely reliable and very suitable
for hobbyists, audiophiles, car audio dealers, home au­dio listeners, studio and recording system engineers, and
pro-audio contractors

Background: When more than one speaker is used in a
system, it is important that the direction of cone move­ment of each and every speaker be the same. Any
speaker moving opposite to the rest will detract from
the effect in a manner not at all unlike a single boat
rower pulling opposite of the majority. Next, consider
the boat as a system with two rowers pulling when ten
rowers are pushing It is obvious that the boat will func­tion much better with all twelve rowers pulling and push­ing together.

Natural sound travels in chain-reaction type waves made
up of high-pressure and low-pressure fronts. In nature,
all sound waves emanating from a free radiating source
travel in the same direction - out and away from that
source.

INSTRUCTION MANUAL

electrical polarity. In most cases, a red dot or a + sign is
placed on or near the terminal of the voice coil known
as the positive terminal. By default, the other terminal
is known as the negative terminal. When a DC poten­tial is applied to the voice coil so that the positive voice
coil terminal is connected to the + potential and the
negative voice coil terminal is connected to the poten­tial, the cone of the speaker usually moves out and away
from the basket and magnet structure. However, this is
not always the case because some speaker manufactur­ers choose to label their terminals otherwise.

Another problem is that, due to phase shift the output of
a Passive crossover is delayed with respect to the input
at certain frequencies. The amount of delay depends on
the order of the filter network. For instance, the output
of a second order crossover (12 dB/octave) is shifted by
180 degrees near the crossover frequency. Some cross­over manufacturers and some enclosed speaker manu­facturers choose to reverse the electrical polarity of the
crossover’s output to minimize this effect Other manu­facturers choose not to reverse the output. This means
that the end user of pre-assembled or “home-brew” pas­sive crossovers cannot be sure of the final polarity with­out actually testing the system.

Many cars and homes are pre-wired for sound systems.
Making sure of the wire polarity can be a tedious task.
With car audio, removing factory door panels or lifting
a dashboard can be a difficult task. For these reasons,
we have seen many car audio systems with two or more
speakers working against the rest of the system. With
woofers, this problem manifests itself as a tremendous
lack of bass. With midrange and higher frequency speak­ers, the problem leads to flaws in the staging and over­all poor performance.

A dynamic loudspeaker is a two terminal device that
features a voice coil of wire placed in a permanent
magnetic hole. The voice coil is fastened to a rigid
speaker cone that is capable of moving in only two di­rections, forwards and backwards. Basic physics tells us
that when an electric current flows in the voice coil, the
coil will either be pulled into the magnet or pushed away
from the magnet. The determining factor for the direc­tion of coil (and cone) movement is the polarity of the
electric current flowing in the windings. T his means that
simply reversing the direction of current (polarity) will
reverse the direction of cone movement.

The Problem: When speakers are manufactured the voice
coil terminals are usually marked with respect to their

Contemporary car audio Often features OEM upgrades
and that typically leads to the use of devices known as
Line Output Converters, Floating Ground Adapters, and
Ground Loop Isolators. The problem here is that man y of
these inexpensive devices invert the audio signal. This
means that a positive signal entering the device becomes
a negative signal at the output. Likewise, there are many
active electronic components that invert the signal.

Although not necessarily a problem for that individual
component as soon as that component is added to a
system, the amplifiers and speakers fed by this compo­nent will be out of polarity with the rest of the system.

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SYSTEM 2000 POLARITY CHECKER

Many components cause a polarity inversion in the sig­nal Power amplifiers are r arely specified for this attribute,
yet it can cause difficulty in multiple amplifier systems.
Large commercial systems that use hundreds of speak­ers and complex wiring schema can be easily checked
in minutes instead of hours aging the Polarity Checker.

Visibly checking speaker polarity with a small flash­light battery accomplishes little except verifying the
factory labels on the voice coil terminals. Proper polar ­ity verification requires checking the speaker wires, the
amplifier, the equalizer all the way to the deck.

Familiarization: T he operator should be familiar with the
Checker before testing systems. First you’ll need to place
a 9-volt battery inside your Polarity Checker and then
you’ll need a quiet room to make some tests. To under­stand the concept of speaker polarity, place the Polarity
Checker on a table or counter top with the Polarity
Checker’s microphone end slightly protruding over one
edge. Press the centered “on” button and notice that the
green and/or red LEDs may blink. If the LEDs are blink­ing, it means that the microphone is picking up too much
ambient noise to make valid measurements. Find a qui­eter location.

that the sound energy is insufficient to measure polarity .
Although you can slam the book harder to force the LEDs
to light, reflections from the floor , walls, tables and y our
body will begin to affect the measurements. It is best to
keep the microphone very close to the flat object and/or
the speaker’s cone.

Set the Polarity Checker do wn or the table and sing into
the microphone until the LEDs stop blinking. Notice
that approximately 5 minutes time has elapsed. This is
how the auto-off circuitry works.

Checking Polarity: Place the test software into a CD
player, set the repeat track and then use the balance
and fader controls so that only one speaker is playing at
a time. It is always best to test one speaker at a time.
The polarity pulses on the test softw are are recorded with
two consecutive positive pulses immediately followed
by a single, equal but opposite negative pulse. The soft­ware actually creates the electrical equivalent of the
book’s positive and negative directions of travel. The
timing and duration of the specially recorded pulses
makes it possible for the Polarity Checker to actually
checks itself so as to accurately verify its readings. Fol­lowing is the order of the recorded software pulses:

Obtain a small flat object such as a book, magazine,
CD case, or a plate. Using one hand, hold the book
about 1 foot away from, and directly in front of, the
Polarity Checker’s microphone. Make sure that the Po­larity checker’s microphone is the closest thing to the
book so that reflections will not be entering into this
test. With your other hand, sharply tap the book towards
the Polarity Checker’s microphone. T he green LED should
light. When the flat surface moves towards the micro­phone, we call it a positive direction of travel. Try this
experiment again and notice that each time you tap the
book toward the microphone the green LED lights, indi­cating that the Polarity Checker recei ved a positive pulse
from the book.

Now, tap the book away from the microphone, notice
that the red LED lights each time the book is tapped
away from the Polarity Checker’s microphone. When
the book moves away from the Polarity Checker’s mi­crophone, we call it a negative direction of travel. Re­peat the experiment and notice that each time the book
is tapped away from the microphone, the red LED lights,
indicating that the Polarity Checker received a nega­tive pulse from the book.

Green Green Red
Green Green Red etc.

With that single speaker playing the test software, posi­tion the microphone of your activated Polarity Checker
directly in front of the speaker’s cone. Be sure to stay
away from ports, passive radiators, and reflective sur­faces. Adjust the volume of the speaker until the LEDs
on the Polarity Checker synchronously blink with the
sound of the pulses- Notice that you cannot easily hear
the difference in polarity, but the Polarity Checker’s cir­cuitry measures the difference. Watch the pattern re­peat over and over.

Let’s say that your Polarity Checker’s LED’s are blinking
Red Red Green. Well, from your familiarization session,
the reason for the reversed pattern is that your sound
system is reproducing the exact opposite of the worded
pulses. Actually your system is creating a mirror image
reproduction of all software not just our test CD. We’ll
talk more about this later. The important aspect of this
test is the repeatable pattern of either Green Green Red,
indicating a faithful reproduction of the software or Red
Red Green, indicating a mirror image reproduction

Move the book out farther aw ay from the P olarity Checker
and repeat the experiment. Notice that as you get four
or more feet awa y, the LEDs no longer light. T his means

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If the LEDs are blinking randomly or all Red or all Green,
then something is wrong with either the sound system,
the Polarity Checker, or the way in which you are per-