Mackie SRM 450 Guide

SRM450 ACTIVE
SOUND REINFORCEMENT
SPEAKER USER’S MANUAL
AND WARRANTY REGISTRATION

CAUTION AVIS
RISK OF ELECTRIC SHOCK
DO NOT OPEN
RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK
DO NOT REMOVE COVER (OR BACK)
NO USER-SERVICEABLE PARTS INSIDE
REFER SERVICING TO QUALIFIED PERSONNEL
ATTENTION: POUR EVITER LES RISQUES DE CHOC
ELECTRIQUE, NE PAS ENLEVER LE COUVERCLE. AUCUN
ENTRETIEN DE PIECES INTERIEURES PAR L'USAGER. CONFIER
L'ENTRETIEN AU PERSONNEL QUALIFIE.
AVIS: POUR EVITER LES RISQUES D'INCENDIE OU
D'ELECTROCUTION, N'EXPOSEZ PAS CET ARTICLE
A LA PLUIE OU A L'HUMIDITE
The lightning flash with arrowhead symbol within an equilateral
triangle is intended to alert the user to the presence of uninsulated
"dangerous voltage" within the product's enclosure that may be
of sufficient magnitude to constitute a risk of electric shock to persons.
Le symbole éclair avec point de flèche à l'intérieur d'un triangle
équilatéral est utilisé pour alerter l'utilisateur de la présence à
l'intérieur du coffret de "voltage dangereux" non isolé d'ampleur
suffisante pour constituer un risque d'éléctrocution.
The exclamation point within an equilateral triangle is intended to
alert the user of the presence of important operating and maintenance
(servicing) instructions in the literature accompanying the appliance.
Le point d'exclamation à l'intérieur d'un triangle équilatéral est
employé pour alerter les utilisateurs de la présence d'instructions
importantes pour le fonctionnement et l'entretien (service) dans le
livret d'instruction accompagnant l'appareil.
7. Heat — This Mackie product should be situated away from heat
sources such as radiators, or other devices which produce heat.
8. Power Sources — This Mackie product should be connected to a
power supply only of the type described in these operation
instructions or as marked on this Mackie product.
9. Power Cord Protection — Power supply cords should be routed
so that they are not likely to be walked upon or pinched by items
placed upon or against them, paying particular attention to cords at
plugs, convenience receptacles, and the point where they exit this
Mackie product.
10. Object and Liquid Entry — Care should be taken so that
objects do not fall into and liquids are not spilled into this Mackie
product.
11. Damage Requiring Service — This Mackie product should be
serviced only by qualified service personnel when:
A. The power-supply cord or the plug has been
damaged; or
B. Objects have fallen, or liquid has spilled into this
Mackie product; or
C. This Mackie product has been exposed to rain; or
D. This Mackie product does not appear to operate
normally or exhibits a marked change in performance;
or
E. This Mackie product has been dropped, or its chassis
damaged.
12. Servicing — The user should not attempt to service this
Mackie product beyond those means described in this operating
manual. All other servicing should be referred to the Mackie Service
Department.
13. To prevent electric shock, do not use this polarized plug with an
extension cord, receptacle or other outlet unless the blades can be
fully inserted to prevent blade exposure.
Pour prévenir les chocs électriques ne pas utiliser cette fiche
polariseéavec un prolongateur, un prise de courant ou une autre
sortie de courant, sauf si les lames peuvent être insérées àfond
sans laisser aucune pariie àdécouvert.
14 . Grounding or Polarization —Precautions should be taken so
that the grounding or polarization means of this Mackie product is
not defeated.
15 . This apparatus does not exceed the Class A/Class B (whichever
is applicable) limits for radio noise emissions from digital apparatus
as set out in the radio interference regulations of the Canadian
Department of Communications.
ATTENTION —Le présent appareil numérique n’émet pas de bruits
radioélectriques dépassant las limites applicables aux appareils
numériques de class A/de class B (selon le cas) prescrites dans le
règlement sur le brouillage radioélectrique édictépar les ministere
des communications du Canada.
SAFETY INSTRUCTIONS
1. Read Instructions —All the safety and operation instructions
should be read before this Mackie product is operated.
2. Retain Instructions —The safety and operating instructions
should be kept for future reference.
3. Heed Warnings —All warnings on this Mackie product and in
these operating instructions should be followed.
4. Follow Instructions —All operating and other instructions
should be followed.
5. Water and Moisture —This Mackie product should not be used
near water –for example, near a bathtub, washbowl, kitchen sink,
laundry tub, in a wet basement, near a swimming pool, swamp or
salivating St. Bernard dog, etc.
6. Ventilation —This Mackie product should be situated so
that its location or position does not interfere with its proper
ventilation. For example, the Component should not be situated
on a bed, sofa, rug, or similar surface that may block any
ventilation openings, or placed in a built-in installation such as a
bookcase or cabinet that may impede the flow of air through
ventilation openings.
PORTABLE CART WARNING
Carts and stands - The
Component should be used
only with a cart or stand
that is recommended by
the manufacturer.
A Component and cart
combination should be
moved with care. Quick
stops, excessive force, and
uneven surfaces may cause
the Component and cart
combination to overturn.
WARNING —To reduce the risk of fire or electric
shock, do not expose this appliance to rain or moisture.

3
Part No. 820-158-00 Rev. C 10/2000
©2000 Mackie Designs Inc. All Rights Reserved. Printed in the U.S.A.
Lend Me Your Ears
Exposure to extremely
high noise levels may
cause permanent hear-
ing loss. Individuals vary
considerably in susceptibility to noise-in-
duced hearing loss, but nearly everyone will
lose some hearing if exposed to sufficiently
intense noise for a period of time. The U.S.
Government’s Occupational Safety and
Health Administration (OSHA) has speci-
fied the permissible noise level exposures
shown in this chart.
According to OSHA, any exposure in
excess of these permissible limits could
result in some hearing loss. To ensure
against potentially dangerous exposure to
high sound-pressure levels, it is recommend-
ed that all persons exposed to equipment
capable of producing these levels use hearing
protectors while this unit is in operation.
Ear plugs or protectors in the ear canals or
over the ears must be worn when operating
this amplification system in order to prevent
a permanent hearing loss if exposure is in
excess of the limits set forth here.
Duration Per Day Sound Level dBA, Typical
In Hours Slow Response Example
8 90 Duo in small club
692
4 95 Subway Train
397
2 100 Very loud classical music
1.5 102
1 105 Patrice screaming at Ron about deadlines
0.5 110
0.25 or less 115 Loudest parts at a rock concert
CONTENTS
INTRODUCTION ....................................................... 4
HOOKUP DIAGRAMS ............................................... 6
Quick Start ........................................................ 6
REAR PANEL DESCRIPTION .................................... 8
IEC Socket .................................................. 8
POWER Switch ............................................ 8
POWER ON Indicator ................................... 8
TIMED TURNOFF ......................................... 8
THERMAL Indicator ..................................... 8
CONTOUR ................................................... 9
LOW CUT .................................................... 9
LEVEL ......................................................... 9
SIGNAL PRESENT Indicator ........................ 9
PEAK Indicator ............................................ 9
INPUT Connector ........................................ 9
THRU Connector ......................................... 9
ACCESSORY Plate ...................................... 9
CONNECTIONS ...................................................... 10
PLACEMENT .......................................................... 10
RIGGING ................................................................ 11
THERMAL CONSIDERATIONS ................................ 12
AC POWER CONSIDERATIONS .............................. 12
SERVICE INFORMATION ........................................ 14
Warranty Service ............................................. 14
Troubleshooting ............................................... 14
Repair ............................................................. 16
CARE AND MAINTENANCE .................................... 16
SPECIFICATIONS ................................................... 17
BLOCK DIAGRAM .................................................. 18
SRM450 LIMITED WARRANTY ............................... 19
Don’t forget to visit our website at www.mackie.com
for more information about these and other Mackie products.
The SRM450
can produce a
maximum SPL
of 127 dB @ 1m.

4
INTRODUCTION
Thank you for choosing Mackie Designs’
active sound reinforcement speakers.
The SRM450 is an active two-way loud-
speaker capable of extremely high sound
pressure levels, and designed to give you the
best performance of any loudspeaker in its
class and price range.
Our design goal was to build a sound re-
inforcement speaker with the same fidelity
and flat frequency response found in our
reknowned HR824 studio monitors. We
think you’ll agree that the SRM450 sound
quality and accuracy reaches this goal and
more. The result is a sound reinforcement
system equally at home in a concert setting,
in the studio, impromptu concerts on the
studio roof, in the cinema, or in a home the-
ater.
Mackie Designs’ entry into the sound
reinforcement loudspeaker market began
with the acquisition, in June of 1998, of
Radio Cine Forniture (RCF), headquartered
in Reggio Emilia, Italy. RCF has a long tra-
dition in developing speaker technology for
the high-end pro-audio market.
The Transducers
The SRM450 active speakers feature a
12” high-power low-frequency woofer and
a 1.75” titanium diaphragm high-output
precision compression driver. This high
frequency driver is mounted on an acousti-
cally non-resonant exponential waveguide,
providing a wide, controlled dispersion and
precise reproduction of the critical upper
mid-range and high frequencies. The result
is an unbelievably smooth off-axis response
that allows everyone in the audience to
experience the same high-resolution audio
no matter where they are seated.
Each driver has been specifically designed
by our engineers for optimum performance
in the lightweight high-strength cabinet.
FR Series Power Amplifiers
To power these beautiful things, each
SRM450 includes two of our acclaimed FR
Series “Fast Recovery” power amplifiers. Our
exclusive design uses low negative feedback,
yet allows the amplifiers to maintain low dis-
tortion and stability and to quickly recover
when driven into clipping.
The amplifiers include the following
features:
• The low-frequency amplifier produces
up to 540 watts peak (300 continuous)
before clipping.
• The high-frequency amplifier produces
up to 150 watts peak (100 continuous)
before clipping.
• Each amplifier has its own compressor
circuit that acts when the input signal is
large enough to cause clipping, distor-
tion and excessive voice coil heat. The
compressor will automatically decrease
the input signal to a safe level. The
compressor in the low-frequency amp
works independently from that in the
high-frequency amp.
• The low-frequency amp uses a servo
feedback loop which senses the current
flowing in the woofer coil. This controls
the low-frequency response and main-
tains low distortion at high output levels.
• The low-frequency amplifier also has a
sweeping filter. This will automatically
move the low cut-off frequency up or
down depending on the amplifier
output. For example, if the amplifier is
below clipping, the low-frequency cut-
off point is 55Hz. As it approaches
clipping, this shifts up smoothly to
120Hz, providing more power reserves
and less distortion before clipping. This
happens quickly and continuously,
protecting the amplifer and the woofer
and reducing any noticable distortion.
Warning: Although the
amplifiers have these
protection circuits, you
must still make sure the
PEAK light is not blink-
ing continuously. If it is, turn down your
mixer faders, or preamplifier gain, or turn
down the SRM450 LEVEL control.

5
The Crossover
The built-in electronic crossover is a
24 dB/octave Linkwitz-Riley design.
Although more expensive than other cross-
over designs, the benefits provided by the
Linkwitz-Riley design have been well docu-
mented. These benefits include:
• Absolutely flat frequency response
throughout the bandpass, without the
characteristic ripple near the crossover
point exhibited by other designs.
• The sharp 24 dB per octave roll-off of
the filters ensures that the transducers
aren’t reproducing frequencies outside
of their capabilities.
• The acoustic sum of the two driver
responses is unity at the crossover
frequency, resulting in perfect power
response.
• Our heroic engineers have worked
carefully to ensure that the SRM450
also provides perfect phase response.
This diligence has yielded phenomenal
accuracy, even if you are standing 20
feet away.
The Cabinet
The SRM450 cabinet was designed to be
the strongest molded composite cabinet on
the planet. This material is as strong as con-
crete, and rigid enough to prevent
unwanted vibrations in the cabinet. It has
built-in fly points for hanging, and a socket
in the bottom for mounting on a tripod
stand. Although it is an exceptional choice
for installed sound situations, its light
weight and durable finish also make it ideal
for portable sound system use. The asym-
metrical trapezoidal design of the cabinet
makes it easy to use as a floor wedge for
stage monitor applications.
The Active Advantage
There are a number of advantages to us-
ing an active speaker system over a passive
loudspeaker:
• The internal crossover is active, and its
low power circuitry operates on line-
level signals. It does not waste
speaker-level power like a passive
crossover with large coils, caps, and
resistors.
• The input signals are crossed over
before they reach the amplifiers, so each
amplifier only receives the correct
frequency range for its driver.
• The amplifiers are designed specifically
for these speaker load impedances.
There is no guesswork as to what load
each amplifier has to drive, so they can
provide maximum acoustic output from
the speakers, yet minimize the danger of
speaker damage due to overdriving a
lesser amplifier.
• The connecting wires between the
amplifier outputs and the drivers are
kept to a minimum, so the damping
factor of the amplifier isn’t compro-
mised by the resistance of long speaker
cables. In addition, all the power from
the amplifier is transferred directly to
the drivers with no speaker cable losses.
• The acoustic sum of the outputs from
the two drivers is optimized electroni-
cally, as well as physically, so the
amplitude response is flat and there is
no lobing error.
• The presence of active circuits within
the speaker cabinet allow the designer
to add on extra details, such as a high
quality mic/line input section and
optional accessory modules.
In short, all the complex interconnected
components in the system are designed to
work in harmony with each other to pro-
duce the best possible sound. (Even for
Uncle Bert’s star performance on spoons!)

6
HOOKUP DIAGRAMS
Quick Start
1. Start with the following settings on the
back of the SRM450:
Turn the POWER switch off (down).
Set the TIMED TURNOFF, CONTOUR,
and LOW CUT switches out.
WARNING: Turn the
LEVEL control down
(counterclockwise)
before every use. If not,
you could be in for a
startling surprise, especially if the last
time you used it was with a microphone
and now you want to connect a line-
level source.
2. Connect the output from your signal
source (mixing console, microphone,
preamp, or other mic- or line-level
source) directly to the INPUT connector
on the back of the SRM450. It accepts
balanced line-level signals from mixers,
preamplifiers, CD players, tape decks,
etc., and accepts direct connections from
dynamic microphones.
3. Connect the supplied AC power cord to
the IEC socket on the back of the
SRM450. Plug the other end into an AC
outlet properly configured with the
correct voltage for your particular model.
4. Turn on your signal source. Make sure its
Master Volume control (if it has one) is
turned all the way down.
5. Turn on the SRM450 POWER switch.
6. Start the signal source, whether it be
speaking into a microphone or starting a
CD player. Adjust any volume controls on
the signal source for normal operation.
7. Slowly turn up the LEVEL control on
the back of the SRM450 until the
desired volume is reached (and the
PEAK light does not come on). Always
wear hearing protectors if you are close
when it is playing at high levels.
8. If there is no sound, always turn down
the SRM450 LEVEL control before
investigating. There may be a mixer or
preamplifier mute or tape switch
engaged, or a mic switch off.
Mixer or
Preamplifier
Right
Line level
Output
Left
Line level
Output
Thru
Thru
Next
Next
1202-VLZPRO
1202-VLZPRO
SRM450: STEREO OPERATION WITH A MIXER, AND USING THE THRU JACK
Daisy-chaining
SRM450s

7
THRU
Output
Dynamic
Microphone
SRM450: USING A MICROPHONE AND THE THRU JACK
Po w e r
Cord
Po w e r
Cord
Pole
Mount
Pole
Mount
Line-level
Hi-pass
out
Line-level
Hi-pass
out
Full
Range
Full
Range
Po w e r
Cords Po w e r
Cords
SRS1500
plays the low
frequencies
SRS1500
plays the low
frequencies
1202-VLZPRO
SRM450: BIAMPING WITH A POWERED SUBWOOFER
The SRM450 can be
used with a Mackie
SRS1500 Subwoofer to
create an incredibly
powerful system.
The active crossover
inside the SRS1500
splits the full range in-
put signal into two
ranges. The SRS1500
plays the low frequency
range through its 600
watt amplifier and 15-
inch woofer, and sends
the high-pass range to
the SRM450.
The SRM450 can be
pole mounted on top of
the SRS1500 as shown,
saving the cost of a
tripod stand.
For microphone connections, you can
daisy-chain up to two SRM450s using the
THRU jacks as shown.
Take great care to point any micro-
phones away from the SRM450s, otherwise
you may get feedback.

8
REAR PANEL DESCRIPTION
TIMED TURNOFF
When this switch is pushed in, the built-
in amplifiers turn on and off depending on
the presence or absence of an input signal.
An input signal level of –45 dBu (mini-
mum) activates the auto-on function. A
silent period greater than three minutes
activates the auto-off function. The blue
LED on the front of the speaker reflects the
state of the amplifiers.
THERMAL Indicator
This LED lights if the heatsink tempera-
ture exceeds a safe operating temperature
and triggers the thermal safety switch.
When this occurs, the built-in amplifiers
shut down until the heatsink temperature
cools back down. Then the thermal switch
resets itself, the THERMAL indicator turns
off, and normal operation resumes.
If the SRM450 keeps
shutting down, make
sure there is plenty of
ventilation to the rear
panel. Please see “Ther-
mal Considerations” on page 12.
The SRM450 has several connectors,
controls, and indicators that you should
understand.
IEC Socket
This is where you connect the supplied
AC linecord to provide AC power to the
SRM450’s built-in power amplifiers. Plug
the linecord into an AC socket properly
configured for your particular model.
Note: If you happen to lose the AC
linecord, replacements are readily available
at any office or computer supply store. Al-
ways use a three-pin plug with a ground
pin.
POWER Switch
Switch up to turn the SRM450 on, and
switch down to turn it off. Make sure the
level control is down before you turn it on.
POWER ON Indicator
When the POWER switch is turned on,
and the linecord is connected to an active
AC Mains supply, this indicator, located
just above the POWER switch, glows to let
you know that you’re ready to rock and
roll. The cool blue LED on the front of the
speaker works in the same way.

9
CONTOUR
Pushing in this switch engages a filter
that provides 3 dB of boost to the low and
high frequencies (below 100Hz and above
12kHz). This provides a punchy, crisp
sound for most live music applications. You
can experiment with this switch by leaving
it out for a while, then pushing it in to de-
termine which way sounds best for your
application. It is especially useful when lis-
tening at lower volumes, as it highlights the
bass like a Loudness switch, in addition to
boosting the highs.
LOW CUT
Pushing in this switch engages a low-cut
filter, which rolls off the low frequencies be-
low 75Hz. This is useful for minimizing
stage noise (rumble) and microphone han-
dling noise.
It is highly recommended
that you engage this
switch when using the
SRM450 as a stage moni-
tor. This allows the bass
amplifier to utilize its power for those fre-
quencies useful in stage monitor
applications.
LEVEL
This is used to adjust the signal level, go-
ing into the built-in power amplifiers, from
Off up to 40 dB of gain. Since the SRM450
incorporates Mackie’s world-class low-noise
mic preamp technology, you can connect ei-
ther a line-level or a microphone-level signal
to the input, and use this control to adjust
the level correctly.
There is no phantom
power for a microphone,
so you should use a
dynamic mic, or use a
condensor type if it has
its own battery power.
Follow the Quick Start guide on page 6
for setting the LEVEL control. For most ap-
plications, it will be in the NORMAL
position (12 o’clock) . If you have a particu-
larly high line-level signal connected to the
SRM450, you may need to turn the control
down to the LINE indication (9 o’clock). If
you have a low line-level or mic-level signal
connected, you may need to turn the
LEVEL control up to the MIC indication
(3 o’clock).
SIGNAL PRESENT Indicator
This LED illuminates whenever there is
a signal present at the INPUT connector on
the rear panel. It senses the signal just prior
to the LEVEL control, so even if the LEVEL
control is turned down, the SIGNAL
PRESENT indicator still works.
PEAK Indicator
When the signal levels at the amplifier
outputs approach clipping, a soft compres-
sion circuit is activated that reduces the
input signal. The PEAK LED lights when-
ever the compression circuit is active. At
this time, the SRM450 may reach sound
pressure levels of 120 dB or more.
It’s okay for the PEAK indicator to blink
occasionally, but if it blinks frequently or
continuously, either turn down the signal
level at the mixer or other signal source, or
turn down the SRM450’s LEVEL control.
Wear hearing protection
if you are close to the
SRM450 playing at high
levels.
INPUT Connector
This is a female XLR-type connector that
accepts a balanced or unbalanced mic- or
line-level signal.
THRU Connector
This is a male XLR-type connector that
produces exactly the same signal that is
connected to the INPUT jack. It can be a
balanced or unbalanced mic- or line-level
signal. Use it to daisy-chain several active
speakers together off the same signal
source.
ACCESSORY Plate
This removable plate provides access to
install future accessory modules.

10
PLACEMENT
The SRM450 active speakers are de-
signed to sit on the floor, a tabletop, or to fit
on a standard tripod speaker stand. They
can also be suspended by the rigging points,
shown opposite.
You can lay the cabinet down on its side
and use the SRM450 as a floor monitor. The
asymmetrical trapezoidal shape of the cabinet
provides a perfect angle for aiming up toward
performers from the front of the stage. When
used for monitor applications, we recom-
mend engaging the LOW CUT filter.
As with any powered
components, protect
them from moisture. If
you are setting them up
outdoors, make sure they
are under cover if you expect rain.
The SRM450 generates
magnetic fields. Do not
place them closer than 2
or 3 feet (60-100 cm)
from TV or computer
monitors. Check the screen for any change
in color or distortion. Do not place any
magnetic audio or video tapes or computer
discs near the SRM450s.
Room Acoustics
The SRM450 active speakers are de-
signed to sound as neutral as possible; that
is, to reproduce the input signal as accu-
rately as possible, monitoring the sound
rather than changing it.
Room acoustics play a crucial role in the
overall performance of a sound system.
However, the wide high-frequency disper-
sion of the SRM450 helps to minimize the
problems that typically arise.
Balanced XLR Connectors
CONNECTIONS
The SRM450 has a female XLR input
that accepts a balanced or unbalanced mic-
or line-level signal. When connecting a bal-
anced signal, be sure it’s wired per AES
(Audio Engineering Society) standards:
XLR
Hot (+) Pin 2
Cold (–) Pin 3
Shield (Ground) Pin 1
There is also a male XLR connector la-
beled THRU. This allows you to connect
more than one SRM450 to the output of
your mixing console. Simply plug the signal
source output into the first INPUT jack,
and patch that speaker’s THRU jack to the
next INPUT jack, and so on, daisy-chaining
multiple speakers (see diagram on page 6).
There is a limit to how
many you can daisy-chain
together. A general rule is
to maintain a load imped-
ance 10 times or more
than the source impedance to prevent ex-
cessive loading on the source. For example,
if your mixer has an output impedance of
120 ohms, then you can daisy chain up to
sixteen SRM450s. This is a load of 1250
ohms (SRM450 input impedance=20k
ohms; 16 of these in parallel=1250 ohms).
Since microphones typically have a
higher output impedance, you should limit
daisy-chaining from a mic source to two
SRM450s (see the diagram on page 7).
The THRU jack is wired straight from
the INPUT connector — there is no elec-
tronic circuitry between — so the signal
coming out of the THRU jack is exactly the
same as the signal going in.
Top
900 Dispersion
up to 18kHz
90
0

11
Here are some other placement tips:
• Avoid placing loudspeakers in the corners
of a room. This increases the low-fre-
quency output and can cause the sound to
be muddy and indistinct.
• Avoid placing loudspeakers against a wall.
This, too, increases the low frequency output,
though not as much as corner placement.
However, if you do need to reinforce the low
frequencies, this is a good way to do it.
• Avoid placing the active speakers directly on
a hollow stage floor. A hollow stage can
resonate at certain frequencies, causing peaks
and dips in the frequency response of the
room. It’s better to place the active speakers
on a sturdy table or tripod stands.
• Position the active speakers so the high-
frequency drivers are 2 to 4 feet above ear
level for the audience (make allowances for a
standing/dancing in the aisles audience).
High frequencies are highly directional and
tend to be absorbed much easier than lower
frequencies. By providing direct line-of-sight
from the active speakers to the audience, you
increase the overall brightness and intelligibil-
ity of the sound system.
• Highly reverberant rooms, like many gymna-
siums and auditoriums, are a nightmare for
sound system intelligibility. Multiple reflec-
tions off the hard walls, ceiling, and floor play
havoc with the sound. Depending on the
situation, you may be able to take some steps
to minimize the reflections, such as putting
carpeting on the floors, closing draperies to
cover large glass windows, or hanging
tapestries or other materials on the walls to
absorb some of the sound.
However, in most cases, these remedies are
not possible or practical. So what do you do?
Making the sound system louder generally
doesn’t work because the reflections become
louder, too. The best approach is to provide as
much direct sound coverage to the audience
as possible. The farther away you are from
the speaker, the more prominent will be the
reflected sound.
Use more speakers strategically placed so
they are closer to the back of the audience. If
the distance between the front and back
speakers is more than about 100 feet, you
should use a delay processor to time-align the
sound. (Since sound travels about 1 foot per
millisecond, it takes about 1/10 of a second to
travel 100 feet).
SRM450
Rigging Points
Both SidesBack
BottoTop
Pole
Mount
RIGGING
The SRM450 cabinets are fitted with rig-
ging points shown in the diagram below.
WARNING: Never at-
tempt to suspend the
SRM450 active speakers
by their handles. If you
want to suspend them,
use the rigging points only.
Full details concerning rigging the
SRM450s can be found with Mackie’s
Certified Rigging Accessories, including
hardware and information on safe working
loads. Contact your Mackie dealer or see
our website for details.
If you are hanging them
in an inaccessable place,
such as over a lion’s cage,
make sure that you first
complete the sound check
and set the SRM450 LEVEL correctly. Also
set the TIMED TURNOFF switch if you
want the SRM450 to turn on when there is
a signal present. It will also turn off after
three or more minutes of silence.

12
HEATSINK
THERMAL
TRANSFORMER
120V
120V
240V
HIGH VOLTAGE POWER LINE
EARTH
GROUND
(NEUTRAL)
PRIMARY
WINDING
SECONDARY
WINDING
240V CENTER-TAPPED SECONDARY
PEAK
LOW CUT
AC POWER
CONSIDERATIONS
Be sure the SRM450 is plugged into an
outlet that is able to supply the correct volt-
age specified for your model. If the voltage
should drop below 97% of the specified line
voltage, the built-in amplifiers will no
longer be able to supply rated power. (They
will continue to operate down to 75% of
the rated line voltage, but won’t reach full
power, resulting in lower headroom).
Under maximum S.P.L. conditions,
where musical peaks are clipping, the
SRM450 120V model draws 2.5 amps on
average (1.3 amps for the 240V model). Un-
der normal conditions, the current draw is
below 1 amp.
We recommend that a stiff (robust) sup-
ply of AC power be used because the
amplifiers place high current demands on
the AC line. The more power that is avail-
able on the line, the louder the speakers will
play and the more peak output power will
be available for cleaner, punchier bass. A
suspected problem of “poor bass perfor-
mance” is often caused by a weak AC
supply to the amplifiers.
AC Power Distribution
A 240VAC center-tapped service en-
trance transformer serves the majority of
AC outlets encountered in homes and clubs
(in the U.S.). This provides two phases of
AC power on either side of the center tap,
at 120V each.
If lighting is used in a show, it is prefer-
able to power the lights from one leg of the
service, and power the audio equipment
from the other leg. This will help minimize
noise from the lights coupling into the au-
dio (particularly if SCRs, or light-dimmer
switches, are used).
THERMAL
CONSIDERATIONS
The amplifiers inside
the SRM450 are con-
vection cooled by a
large heatsink. For ef-
ficient cooling, it is
important to allow at least six inches of
free space behind the SRM450.
If you use the SRM450
on its side for stage
monitor applications,
we highly recom-
mended that you engage
the rear panel LOW CUT switch. This will
allow more power for useful monitor fre-
quencies, while reducing the possibility of
overheating.
If the ambient temperature in the
room is high, it could cause the amplifi-
ers to overheat. In this case, you should try
aiming a fan at the heatsink to increase the
air flow through the fins.
During a performance, don’t have it
cranked so high that the rear panel PEAK
LED is blinking frequently or lighting con-
tinuously. You should turn down the
LEVEL control a notch or two to avoid
overheating the amplifiers or your neigh-
bors.
If the amplifiers do overheat, a built-in
thermal switch will activate, placing the
amplifiers into standby. When the amplifi-
ers have cooled down to a safe operating
temperature, the thermal switch will reset
and the SRM450 will resume normal opera-
tion.

13
Wherever possible, connect all of your
equipment to the same electrical circuit.
This will help reduce the possibility of a
ground loop problem causing an annoying
hum in your speakers.
Low power components such as tape
decks, mixers, effects processors and CD
players should be connected to the same
outlet as the SRM450s. Use fused power
strips as shown in the diagram below. Make
sure that the total current draw of your
components does not exceed the capability
of the outlets and power strips.
For the US 120 V model:
A maximum of five SRM450s can be
connected per 15A service.
This allows each SRM450 to be safely
operated at its maximum level.
When turning your system on, turn on
the SRM450s last. This will stop any turn-
on thumps and bangs from your source
equipment being amplified.
When turning off your system, turn off
the SRM450s first. This will prevent any
turn-off thumps and bangs from your
source equipment being amplified.
SRM450 SRM450
When setting up for a
show, often you are plug-
ging into an AC power
distribution system you
know nothing about. You
may even be faced with 2-wire outlets that
are missing the third safety ground pin. It’s
a good idea to have a three-wire AC outlet
tester in your toolbox so you can check the
outlets yourself to make sure they are wired
correctly. These testers will tell you if the
polarity of the hot and neutral wires is re-
versed and if the safety ground is
disconnected.
Don’t use an outlet if it is
wired improperly! This
is to protect yourself as
well as your equipment.
Never remove the
ground pin on the power
cord of the SRM450 or
any other component.
This is very dangerous.
SRM450: AC CONNECTIONS

14
SERVICE INFORMATION
Warranty Service
Details concerning Warranty Service are
spelled out on page 19 of this manual.
If you think your loudspeaker has a
problem, please do everything you can to
confirm it before calling for service, includ-
ing reading through the following
troubleshooting section. Doing so might
save you from being deprived of your
Mackie loudspeaker.
If you do find the prob-
lem, make sure that you
turn down the LEVEL
controls and turn off the
SRM450 before correct-
ing it or changing any connections.
Of all Mackie products returned for ser-
vice (which is hardly any at all), many are
coded “CND” — Could Not Duplicate—
which usually means the problem lay some-
where else in the system. The following
troubleshooting tips may sound obvious,
but here are some things you can check:
Troubleshooting
No power!
• Our favorite question: Is it plugged in?
Make sure the AC outlet is live (check
with a tester or lamp).
• Our next favorite question: Is the
POWER switch on? If not, try turning
it on.
• Is the blue light on the front panel
illuminated? If not, make sure the AC
outlet is live. If so, refer to “No sound”
below.
• The AC line fuse inside the chassis is
blown. This is not a user-serviceable
part. Refer to “Repair” on page 16 to
find out how to proceed.
No sound!
• Is the input LEVEL control turned all
the way down? Follow the procedures
in the “Quick Start” section on page 6
to verify that all the volume controls in
the system are properly adjusted.
• Is the signal source working (and making
union scale)? Make sure the connecting
cables are in good repair and securely
connected at both ends. Make sure the
output volume (gain) control on the
mixing console or preamp is turned up
sufficiently to drive the inputs of the
speaker. You should be able to see the
SIGNAL PRESENT LED blink on the
rear panel.
• Make sure the preamp or mixer does
not have a Mute on, or a Tape or
Processor loop engaged. If you find
something like this, make sure the
volume/gain is turned down before
disengaging the offending switch.
• Is the
THERMAL LED lit? Make sure there
is at least six inches of free space behind
the heatsinks. Allow the SRM450 to cool
off and it will turn back on.
One side is way louder than the other!
• Are the LEVEL controls set the same on
both active speakers?
• Check the PAN control or balance on
the signal source. It may be turned too
far to one side. If you’re using a stereo
signal source, it may be delivering an
out-of-balance stereo signal.
• Try swapping sides: Turn off the active
speakers, swap the input cables coming
from the mixing console, turn the active
speakers back on. If the same side is still
louder, the problem may be with your
active speakers or cables between the
mixer and the active speaker. If the
other side is louder now, the problem is
with the mixer or the signal source.
Poor bass performance
• Check the polarity of the connections
between the mixer/preamp and the
active speakers. You may have your
positive and negative connections
reversed at one end of one cable, causing
one SRM450 to be out-of-phase.
As soon as the music gets loud, the
SRM450 shuts down!
• Be sure that the PEAK LED on the rear
panel is not lighting up frequently or
continuously.
Remember to wear ear
protectors if you get close
to an SRM450 playing at
high levels. When the
PEAK LED comes on,
the SPL is in a region above 120 dB!!!

15
• Make sure there is room behind the rear
panel to provide sufficient ventilation to
the heatsink.
Bad sound!
• Is it loud and distorted? Follow the
procedures described in the “Quick
Start” section to verify that the levels
are set properly.
• Is the input connector plugged com-
pletely into the jack? Be sure all
connections are secure. It’s a good idea
to periodically clean all electrical
connections with a non-lubricating
electrical contact cleaner.
Noise
• Make sure all connections to the active
speakers are good.
• Make sure none of the signal cables are
routed near AC cables, power trans-
formers, or other EMI-inducing devices.
• Is there a light dimmer or other SCR-
based device on the same AC circuit as
the SRM450? Use an AC line filter or
plug the SRM450 into a different AC
circuit.
Hum
• Turn the LEVEL control all the way
down. If the noise disappears, it’s
coming from the signal source. If not,
try disconnecting the cable connected to
the INPUT jack. If the noise disappears,
it could be a “ground loop,” rather than
a problem with the SRM450. Try some
of the following troubleshooting ideas:
• Use balanced connections throughout
your system for the best noise rejection.
• Whenever possible, plug all the audio
equipment’s linecords into outlets which
share a common ground (see the dia-
gram on page 13). The distance between
the outlets and the common ground
should be as short as possible.
Never remove the
ground pin on the power
cord of the SRM450 or
any other component.
This is very dangerous.
• The hum may appear when using an
unbalanced source (consumer preamp,
CD player, VCR, etc.). This is caused by
the unbalanced-to-balanced interface
shield
12
3
XLRRCA 3-Conductor Cable
between the devices (and exacerbated
by the fact that most consumer audio
equipment have a two-wire linecord,
without the third-pin safety ground).
Use an interconnect cable wired as
shown below. The important point is
that the shield and the wire from the
XLR pin 3 are joined at the RCA
(source) end.
• Disconnect any cables which come in
from outside, such as cable TV, satellite
TV or roof top antennas. They must be
disconnected from every part of your
system, such as the TV, VCR and
preamp. If the hum goes away, you can
add a “ground loop isolator” in your
cable line. This is an inexpensive device
available from video or TV dealers, or
you can make your own from two TV
baluns (standard TV 75/300 ohm
adaptors):
The baluns are threaded at one end
(75 ohm) to fit TV coax cable and have
two wires at the other end (300 ohm).
They will not affect the video quality.
• If the hum persists, try removing compo-
nents one at a time from the back of the
mixer or preamplifier, and check for hum
each time (turn off your equipment
before you undo any connections). It is
fairly common to find more than one
problem.
• If your preamp or mixer are the only
things connected to the SRM450s and
the hum is still there, try different
connection cables, or move the preamp/
mixer to another location.
• Pressing the LOW CUT FILTER may
help reduce the hum if you have trouble
finding the cause of the problem. Do this
anyway if you do not need to reproduce
the lower frequency range.
join (+insulate) Balun
Balun

16
REPAIR
Service for the SRM450 is available only
from one of our authorized domestic ser-
vice stations or at the factory, located in
sunny Woodinville, Washington. Service
outside the United States can be obtained
through local dealers or distributors.
If your SRM450 needs service, please fol-
low these instructions:
1. Review the preceding troubleshooting
suggestions. Please.
2. Call Tech Support at 1-800-258-6883,
8am to 5pm PST, to explain the problem
in detail. They will ask you all sorts of
impertinent questions in the hope of
sorting out the problem. If it appears
that the SRM450 needs repair, request
an RA (Return Authorization) number.
Have your speaker’s serial number
ready. You must have an RA number
before you can obtain service at the
factory or an authorized service center.
3. Keep this owner’s manual. We don’t
need it to repair the active speaker.
4. Pack the loud-
speaker in its original
package, including
protective wrap, endcaps,
and box. This is very
important. When you call for the RA
number, please let Tech Support know
if you need new packaging. Mackie is
not responsible for any damage that
occurs due to non-factory packaging.
5. Include a legible note stating your name,
shipping address (no P.O. boxes),
daytime phone number, RA number,
and a detailed description of the prob-
lem, including how we can duplicate it.
6. Write the RA number in
BIG PRINT
on top of the box.
7. Ship the active speaker to us. We
recommend United Parcel Service
(UPS). We suggest insurance for all
forms of cartage. Ship to this address:
Mackie Designs
SERVICE DEPARTMENT
16140 Wood-Red Rd. NE, Ste 5
Woodinville, WA 98072
8. We’ll try to fix the speaker within three
business days. Ask Tech Support for the
latest turnaround times when you call
for your RA number. We normally send
everything back prepaid using UPS
BLUE (Second Day Air). However, if
you rush your speaker to us by Next
Day Air, we’ll treat it in kind by ship-
ping it back to you UPS RED (Next Day
Air). This paragraph does not necessar-
ily apply to non-warranty service.
CARE AND
MAINTENANCE
Your Mackie active speakers will provide
many years of reliable service if you follow
these guidelines:
Avoid exposing the
active speakers to
moisture. If they are set
up outdoors, be sure they
are under cover if you
expect rain or you live in Washington.
• Avoid exposure to extreme cold (below
freezing temperatures). If you must
operate the active speakers in a cold
environment, warm up the voice coils
slowly by sending a low-level signal
through them for about 15 minutes
prior to high-power operation.
• Use a slighty damp cloth with a mild
soap solution to clean the cabinets. Only
do this when the power is turned off.
Avoid getting moisture into any of the
openings of the cabinet, particularly
where the drivers are located.

17
SPECIFICATIONS
Transducer Specifications
Low-Frequency Transducer
Diameter 300mm (12”)
Voice Coil Diameter 63.5mm (2.5”)
Sensitivity (1W@1m) 98 dB
Nominal Impedance 8 ohms
Power Handling 450 watts, program
Frequency Range 45Hz – 3kHz
High-Frequency Driver and Horn
Diaphragm Diameter 44.5mm (1.75˝)
Exit Throat Diameter 25.4mm (1˝)
Diaphragm Material Titanium
Sensitivity (1W@1m) 106 dB
Nominal Impedance 8 ohms
Power Handling 150 watts, program
Frequency Range 1kHz – 20kHz
Horn Type
Composite: Conical/Exponential
Mouth Size
304.8mm (12˝) W x 177.8mm (7˝) H
Horizontal Coverage
90º ±10º (1kHz – 20kHz)
Vertical Coverage
45º ±10º (2.8kHz – 20kHz)
Power Amplifier and System
Specifications
Low-Frequency Power Amplifier
Rated Power 300 watts
Rated THD < 0.1%
Cooling Convection Extrusion
Design Class G, Parametric Servo Feedback
High-Frequency Power Amplifier
Rated Power 100 watts
Rated THD < 0.1%
Cooling Convection Extrusion
Design Conventional Class AB
System Specifications
Input Type Balanced Differential
Input Impedance
Line: 20k ohms
Input Protection RFI and level protected
Sensitivity
Line: +4 dBu (center detent)
Mic: –36 dBu
Maximum Input Level
Line: +22 dBu
Low-Cut Frequency
75Hz, Second-order filter
Acoustic Contour Equalization
Peaking: +3 dB @ 100Hz,
+3 dB @ 12kHz
Enclosure Alignment Sixth-Order
Over-Excursion Protection
Second-Order High-Pass Filter
Thermal Protection Amplifier shutdown,
auto-reset
Low-Line Voltage Shut Down
60% Nominal line
Acoustic Frequency Response
48Hz – 20kHz
Low-Freq –3 dB Point 55Hz
Max Peak SPL @ 1m 127 dB
Low-Freq Crossover 24 dB/octave,
time offset corrected
High-Freq Crossover 24 dB/octave
Crossover Frequency 1.6 kHz
Driver Protection Independent LF and
HF compressors
Low-Freq Roll-Off Dynamic-signal level
dependent
Accessory Interface ±15V DC,
normalized signal I/O
Operating Temperature Range
–10ºC - 45ºC
(14ºF - 113ºF)
Line Input Power
US 120V, 60Hz
Europe 230V, 50Hz
Japan 100V, 50/60Hz
Physical Properties
Height 660mm (25.98”)
Width 390mm (15.35”)
Depth 376mm (14.8”)
Weight 23.2kg (51 lbs.)
Enclosure Geometry
Asymmetrical Trapezoidal
Mounting Methods
Integrated mounting
points, M10
Two each located on each
side, top, bottom, and rear
of enclosure
Disclaimer
Since we are always striving to
make our products better by incor-
porating new and improved
materials, components, and manu-
facturing methods, we reserve the
right to change these specifications
at any time without notice.
“Mackie,” the “Running Man” figure, and
“FR Series” are trademarks or registered trademarks
of Mackie Designs Inc.
All other brand names mentioned are trade-
marks or registered trademarks of their respective
holders, and are hereby acknowledged.
©2000 Mackie Designs Inc.
All Rights Reserved.
Printed in the U.S.A.
14.8"-376mm
25.98"-660mm
14.8"-376mm
15.35"-390mm
15.35"-390mm

18
SRM450 BLOCK DIAGRAM
INPUT
THRU
2
3
1
2
J15
3
1
HI-PASS
LOW CUT CONTOUR
COMPRESSOR
THRESHOLD
COMPRESSOR
SWEEPING
FILTER
LO-PASSDELAY
176uS
HI-FREQ
40-120 Hz
LO-FREQUENCY
DRIVER
TWEET
LO-FREQ
AMP
HI-FREQ
AMP
SENSE
RESISTOR
BASS CONTROL SERVO LOOP
WOOF
PEAK
LIGHT
PEAK
DETECTION
MACKIE DESIGNS
SRM450
BLOCK DIAGRAM
(#071699SE)
THRESHOLD
LPF
THRESHOLD
+
–
MID VDC
+
–LO VDC
+
–
HI VDC
TOROIDAL POWER
TRANSFORMER
FUSE
POWER
SWITCH
ON
OFF
+15VDC
SIGNAL
SENSE
SIGNAL
SENSE MUTE
ON/OFF
CONTROL
MUTE MUTE
POWER
LEDS
THERMAL
LED
THERMAL
SWITCH
LOW AC
VOLTS SENSE
TIMED
TURNOFF
SIGNAL
LED

19
A. Mackie warrants all materials, workmanship and
proper operation of this SRM450 for a period of one
year from the original date of purchase. If you
complete the optional questionnaire portion of the
Product Registration Card, the warranty will be
extended for an additional FOUR years with the
following exception: warranty on all its loudspeaker
components including woofers and compression
drivers are only warranted for an additional one year
(for a total of two years). If any defects are found in
the materials or workmanship or if the product fails
to function properly during the applicable warranty
period, Mackie, at its option, will repair or replace
the product. This warranty applies only to equip-
ment sold and delivered within the U.S. by Mackie
or its authorized dealers.
B. Failure to return the card will not void the 1-year
warranty.
C. Service and repairs of Mackie products are to be
performed only at the factory (see D below) OR at an
Authorized Mackie Service Center (see E below).
Unauthorized service, repairs, or modification will
void this warranty.
D. To obtain factory service:
1. Call Mackie at 800/258-6883, 8AM to 5PM
Monday through Friday (Pacific Time) to get a
Return Authorization (RA). Products returned
without an RA number will be refused.
2. Pack the SRM450 in its original shipping
carton. If you do not have the carton, just ask for
one when you get your RA number, and we’ll
send a shipping carton out promptly. More
information on packing can be found in the
Service section of this manual. Also include a
note explaining exactly how to duplicate the
problem, a copy of the sales receipt with price
and date showing, and your return street address
(no P.O. boxes or route numbers, please!). If we
cannot duplicate the problem at the Mackie
Factory or establish the starting date of your
Limited Warranty, we may, at our option, charge
for service time.
3. Ship the product in its original shipping
carton, freight prepaid to:
Mackie Designs Inc.
SERVICE DEPARTMENT
16140 Wood-Red Road NE, Ste 5
Woodinville, WA, 98072, USA
IMPORTANT: Make sure that the RA number is
plainly written on the shipping carton.
E. To obtain service from an Authorized Mackie Service
Center:
1. Call Mackie at 800/258-6883, 8AM to 5PM
Monday through Friday (Pacific Time) to get:
1) The name and address of your nearest Mackie
Authorized Service Center and 2) A return
authorization (RA). You must have an RA number
before taking your unit to a service center.
2. Make sure that you have a copy of your active
speaker’s sales receipt from the store where you
bought the product. It is necessary to establish
purchase date and thus determine whether or not
your active speaker is still under warranty. If you
can't find it, the Authorized Service Center may
charge you for repairs even if your active speaker is
still covered by Mackie's 1-Year Limited Warranty.
3. Make sure that the problem can be dupli-
cated. If you bring your active speaker to an
Authorized Service Center and they can't find
anything wrong with it, you may be charged a
service fee.
4. If the Mackie Authorized Service Center is
located in another city, pack the active speaker
in its original shipping carton. More information
on packing can be found in the Service section of
this manual.
5. Contact the Mackie Authorized Service Center to
arrange service or bring the active speaker to them.
F. Mackie and Mackie Authorized Service Centers
reserve the right to inspect any products that may
be the subject of any warranty claims before repair
or replacement is carried out. Mackie and Mackie
Authorized Service Centers may, at their option,
require proof of the original date of purchase in the
form of a dated copy of the original dealer’s invoice
or sales receipt. Final determination of warranty
coverage lies solely with Mackie Designs Inc. or its
Authorized Service Centers.
G. Mackie active speakers returned to Mackie and
deemed eligible for repair or replacement under the
terms of this warranty will be repaired or replaced
within thirty days of receipt by Mackie at our
rainforest factory complex. Products returned to
Mackie that do not meet the terms of this Warranty
will be repaired and returned C.O.D. with billing
for labor, materials, return freight, and insurance.
Products repaired under warranty at Mackie's
factory will be returned freight prepaid by Mackie
to any location within the boundaries of the USA.
H. Mackie assumes no responsibility for the quality
or timeliness of repairs performed by Mackie
Authorized Service Centers.
I. This warranty is extended to the original
purchaser and to anyone who may subsequently
purchase this product within the applicable
warranty period.
J. This is your sole warranty. Mackie does not
authorize any third party, including any dealer or
sales representative, to assume any liability on
behalf of Mackie Designs or to make any warranty
for Mackie Designs.
K. THE WARRANTY GIVEN ON THIS PAGE IS THE
SOLE WARRANTY GIVEN BY MACKIE AND IS IN
LIEU OF ALL OTHER WARRANTIES, EXPRESS
AND IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE. THE WARRANTY GIVEN
ON THIS PAGE SHALL BE STRICTLY LIMITED IN
DURATION TO ONE YEAR FROM THE DATE OF
ORIGINAL PURCHASE FROM AN AUTHORIZED
MACKIE DEALER. UPON EXPIRATION OF THE
APPLICABLE WARRANTY PERIOD, MACKIE
SHALL HAVE NO FURTHER WARRANTY OBLIGA-
TION OF ANY KIND. MACKIE SHALL NOT BE
LIABLE FOR ANY INCIDENTAL, SPECIAL, OR
CONSEQUENTIAL DAMAGES THAT MAY RESULT
FROM ANY DEFECT IN THE MACKIE PRODUCT
OR ANY WARRANTY CLAIM. Some states do not
allow exclusion or limitation of incidental, special,
or consequential damages or a limitation on how
long warranties last, so some of the above limita-
tions and exclusions may not apply to you. This
warranty provides specific legal rights and you may
have other rights which vary from state to state.
Please keep your sales receipt in a safe place.
SRM450 LIMITED WARRANTY

®
®
®
™
Mackie Designs Inc.
Mackie Designs Inc.
16220 Wood-Red Rd. NE • Woodinville, WA 98072 • USA
US & Canada: 800/898-3211
Europe, Asia, Central & South America: 425/487-4333
Middle East & Africa: 31-20-654-4000
Fax: [phone] • www.mackie.com
E-mail: [email protected]
Some of the
people at our
factory who helped
design, build, sell,
and support your
product.
Some of the
people at our
factory who helped
design, build, sell,
and support your
product.