This manual describes the
basic operation of the ACOustical
InterfaceTM System.
Installation, system
controls and the actual
operation of the ACOustical
InterfaceTM system
are included. The ACOustical
InterfaceTM system
has four major components: a
measurement microphone;
(1/4, 1/2 and 1 Inch
versions are available), the
companion microphone
preamplifier; the power
supply; windscreen, and
optional PS9
(110VAC). or PS29
(220VAC) AC
adapters. Use of the SPL
Calibrator may be found in
the 511E manual.
INSTALLATION
The microphone system has
three main components: the
microphone capsule; the
preamplifier/ cable and
microphone adaptor (where
applicable).
Preamplifier -
The 4012 preamplifier
has two components. The
preamplifier body with
end-cap (EC2),
and the companion cable with
mating connectors (XLR or
Lemo). The CA4012-5 is
terminated in a 5 pin Male
XLR. This is mates with the
standard PS9200 family of
power supplies. The CA4012-7L is
terminated in a 7 pin Male
Lemotm connector.
The CA4012-L7 pinout is
compatible with the PS9200L7
(2 channel) and PS9204L7
channel) power supplies. It
is also compatible with
Hewlett Packard, Norsonic
and Bruel and Kjaer
instruments equipped with
the mating connector.
4016 - 1/4
Inch preamplifier consists
of the 4012 and
companion cable and the AD0016 1/4
to 1/2 Inch adaptor.
4022 - 1
Inch preamplifier consists
of the 4012 and
companion cable and the AD0122 1
Inch to 1/2 Inch adaptor.
Prepolarized (Electret)
Microphones
CAUTION:
ELECTRET (Prepolarized) MIC
CAPSULES e.g. ACO
Pacific's MK224, 7052H,
7051S or
B&K 4155
require the special CA4012-5E
(CA4012L7E) cable
- designated by yellow or black marking
on the XLR/Lemo end. This
cable has the 200
Vdc polarization connection
removed and
is the polarization
connection at the preamp is
grounded.
Never place
an Electret Capsule on a
standard preamp/cable. This
will cause temporary and
possibly permanent loss of
sensitivity.
The preamplifier body is
detachable from the CA4012XX
cable. This makes for easier
installation of cables and
allows the preamp cable to
be permanently installed.
The preamplifier body may be
detached for safe storage,
testing, or replacement.
Longer CA4012 cables or
CE4012 extension cables are
available on special order.
ATTACH THE CA4012-XX TO
THE PREAMP.
Microphone Installation
The microphone is supplied in a
reusable storage box. 1 inch and
1/2 inch condenser microphones
are supplied with a plastic
protective cap. 1/4 inch
microphones may have a storage
stand. Save
these accessories.
All ACO Pacific measurement
microphones have an
individual "Birth
Certificate". The
certificate provides actual
measured sensitivity data
and frequency response
curves for the specific
capsule. RETAIN
THIS CHART.
The plastic cap provided on
some capsules protects the
stored microphone from
accumulation of dust and
dirt on the diaphragm. The
cap should be stored in the
microphone box as may the
1/4 inch mic stand for the
7016 or 7017.
INSTALLING THE MICROPHONE
CAPSULE -
The microphone end of the 4012 preamplifier
is protected by a machined
metal cap (EC2). This
cap protects the
preamplifier input from
dust, oil and physical
damage when the microphone
is not installed.
To remove - simply unscrew
the cap from the preamp
body.
Save the preamp cap. The cap
may be stored in the
microphone box with the
microphone cap.
1/2 INCH MICROPHONES
Carefully install the
selected microphone capsule
on the face of the
preamplifier - DO
NOT OVERTIGHTEN -
YOU MAY PERMANENTLY DAMAGE
ANY PRECISION MIC BY
EXCESSIVE FORCE - FINGER
TIGHT IS ADEQUATE!
1/4 INCH MICROPHONES
An AD0016 1/4
to 1/2 inch adaptor is
required. Place the AD0016 preamp
adaptor on the face of the
preamp. The ACO
Pacific 4016 Preamp
is this combination.
Carefully place the 1/4 inch
mic capsule on the end of
the 1/4 inch adaptor. DO
NOT OVERTIGHTEN!
1 INCH MICROPHONES
An AD0122 1
inch to 1/2 inch adaptor is
required. Slide the AD0122 1
Inch Mic to 1/2 inch preamp
adaptor over the
preamplifier from the
microphone end and thread in
place. This is the ACO
Pacific 4022 Preamp
combination. Mount the mic
capsule on the
adaptor/preamp combination. DO
NOT OVERTIGHTEN!
The dust cap must be removed
when making measurements.
MICROPHONE GRIDS - DO
NOT REMOVE - It
Is Not Necessary
The grids of most ACO
Pacific microphones are
removable. This
is not necessary for most
measurements. The
microphone is designed for
use with the grid. Removal
will not give you better or
higher or lower readings.
The FREE
FIELD response
curve supplied with Free
Field capsules
assumes the grid is on the
microphone capsule. Removing
the grid does change the
high frequency response.
If you must remove the grid do
so with care. It is very
easy to crease the 2u
thick diaphragm or
even tear it.
In ALL cases DO
NOT OVERTIGHTEN the
grid or the microphone. The
fine threads of both make
over tightening very easy.
PS9200 OPERATION
The PS9200 utilizes a
standard L1604 - 9 Vdc
Alkaline Transistor Radio
Battery. The Battery
Compartment is located on
the bottom of the case below
the BNC cable connectors.
The Power
Switch is
located on the bottom front
of the unit below the Preamp
input connectors. The
Power Switch is a "LOCKING
TOGGLE" TO Turn
ON or to Turn OFF- GENTLY
PULL OUT ON
THE HANDLE BEFORE TOGGLING
THE SWITCH. Up is "ON" and
Down is "OFF".
INSTALLING BATTERY - Not
required for AC operation
First TURN
OFF the PS9200.
Turn over the unit. Slide
open the compartment door
and connect the battery to
the polarized connector in
the compartment. Use caution
- DO NOT
Reverse the Battery
Connections. If
you have accidentally left
the unit turned on - you
will blow the 250 mA fast
blow fuse inside
the PS9200.
Replace the door. BATTERY
LIFE FOR A SINGLE PREAMP
OPERATION IS 50 HOURS -
TYPICAL. As
with all battery powered
devices temperature, type of
battery, and age of the
battery effect operational
battery life. Battery life
with the 4012HP (higher
current version) is much
less - about 10 - 12 hours.
Battery life for the PS9250 is
similarly reduced.
AC OPERATION - 110 Vac
(PS9), 220 Vac (PS29) -
Plugging your PS9 or PS29
into the external power
connection on the side of
the PS9200 disconnects the
battery (removal of the
battery is not necessary).
The PS9200 automatically
disconnects the battery when
external DC is supplied. You
do not need to install a
battery for AC Only
operation.
OPERATION
With a 9 Vdc battery
installed or an AC Adaptor (PS9
or PS29) connected you
are now ready to connect the
microphone preamplifier and
output BNC cables.
ATTACHING THE 4012 or
similar Preamp - Your BNC
signal cable should then be
attached to the BNC
connector directly inline
with the preamp cable. The
label designates these
channels "A" and "B".( Note
the PS9204L7 has only A&B
markings. Designate the
remaining two channels "C"
and "D" as you wish.
The Power
Switch is
located on the bottom front
of the unit - below the
Preamp input connectors. The
Power Switch has a "LOCKING
TOGGLE" TO Turn
On - GENTLY
PULL OUT ON
THE HANDLE BEFORE TOGGLING
THE SWITCH UPWARDS ("ON").
A "LED" indicates
power is applied. also
indicates the battery or
supply voltage is above 6.2
Vdc. A STEADY LED
indicates the battery
voltage is low. You will
have about 1 -2 hours (with
1 preamp) of useful battery
life left when the LED is on
"STEADY". Replace the
battery as soon as possible.
You should not see a steady
LED during normal AC Adaptor
(PS9 or PS29) operation
"TURN ON" TIME - 2-4
minutes -
The extended low frequency
response of the microphones
and the preamplifier result
in long turn on times for
the ACOustical
InterfaceTM System.
Typically this will be about
2 - 4 minutes.
IMPORTANT - THE
PS9200 HAS BEEN DESIGNED TO
REDUCE THE 200
Vdc POLARIZATION
VOLTAGE WHEN NO PREAMPS ARE
PLUGGED IN TO THE SUPPLY. IT WILL
TAKE AT LEAST 1
- 2 MINUTES TO STABILIZE
AFTER THE PREAMP IS
INSTALLED.
YOU WILL NOT READ 200
Vdc ON PIN
3 OF THE SPARE XLR
CONNECTOR. THE OUTPUT
RESISTANCE OF THE CIRCUIT IS 11
MEGOHMS. THIS
IS TO
PROTECT YOU - THE USER.The
typical DVM (Digital
Voltmeter) has 10 MegOhms of
input resistance, creating a
voltage divider. You may
read about 60 to 100 Vdc.
This is not an accurate
reading
CAUTION -
While the input to the 4012 Preamp
is protected against
electrical discharge - use
care when installing and
removing the microphone. If
you accidentally touch the
center pin of the preamp to
the shield or ground the 200
Vdc polarization charge will
be removed and take about 2
minutes to restabilize. A
slow increase in the
sensitivity will be noticed
as the voltage returns.
The ACOustical
InterfaceTM and
microphones are precision
measurement equipment. Designed
for the rigors of field use
they will last for many
years of accurate stable
measurements if properly
treated and maintained.
Acoustic Signal Polarity - A
Reminder
In some measurement
applications, such as
loudspeaker testing, knowing
the absolute polarity of the
acoustic wave is important.
The traditional polarized
measurement microphone has
a positive polarization
voltage on the back plate.
This is an artifact of the
positive plate (anode)
voltage found in tube
(valve) designs. The output
of the traditional
measurement microphone
preamplifier both tube and
solid-state is
non-inverting. These designs
are usually a cathode
(tubes) or JFET source
followers.
As a result of the positive
polarization voltage - positive
going acoustical waves
result in a negative
going electrical signals
from the microphone and
preamplifier. This does not
affect the accuracy of the
measurements but does need
to be taken into account in
some applications
On the other hand - Electret
(prepolarized) microphones
have a negative
polarization voltage (electrons
stored in the electret
material). Positive
going acoustic waves
result in the electron
charge being reduced on the
backplate - thus a positive
going output voltage
is seen. Again, the
measurement accuracy is not
affected.
It is convention for POLARIZED
MEASUREMENT MICROPHONES on
Non-Inverting Preamps to
output:
NEGATIVE GOING SIGNALS FOR
POSITIVE GOING SOUND PRESSURE
For ELECTRET
MICROPHONES on
Non-Inverting Preamps:
POSITIVE GOING SOUND PRESSURE
RESULTS IN POSITIVE GOING
SIGNALS
The preamps of ACO Pacific,
Bruel and Kjaer and others are
Non-Inverting
Optional Equipment
WS1 - 3" Windscreen
The WS1 windscreen
is designed to reduce wind
noise in outdoor
applications. The material
was selected to minimize
attenuation of sound to
beyond 20 kHz. The WS1 may
also be used additional
mechanical protection for
the microphone. It will
protect the microphone
diaphragm from stray
particles, oils and other
materials and act as a
bumber in the case of a
mishap. WS7
- 7" Windscreen
The WS7 windscreen
was designed for higher
velocity wind environments,
like those found in the
desert of the Southwest US.
The WS1 is
adequate for most
applications.
-80T
options- 80ppi Treated for
OUTDOOR USE UV resistant
MATT-XX Microphone
Attenuators
DM2 Series of Dummy
Microphones
The DM2
Series of
dummy microphones permits
the connection of electrical
signals to the input of the 4012 preamplifier.
The DM2-22 dummy
microphone has a 22 pF
coupling capacitor to
simulate a typical 1/2 inch
mic capsule. For more
information read the Dummy
Microphone Users Manual.
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