Behringer Ultracoustic ACX450 User manual

Version 1.1 June 2006
Users Manual
ULTRACOUSTIC ACX450/ACX900/ACX1800

2
ULTRACOUSTIC ACX450/ACX900/ACX1800
IMPORTANT SAFETY PRECAUTIONS
This symbol, wherever it appears, alerts you to
important operating and maintenance instructions
in the accompanying literature. Please read the
manual.
This symbol, wherever it appears, alerts you to the
presence of uninsulated dangerous voltage inside
the enclosurevoltage that may be sufficient to
constitute a risk of shock.
CAUTION: To reduce the risk of electric shock, do not remove
the top cover (or the rear section). No user
serviceable parts inside refer servicing to qualified
personnel.
WARNING: To reduce the risk of fire or electric shock, do not
expose this appliance to rain and moisture. The
apparatus shall not be exposed to dripping or
splashing and no objects filled with liquids, such
as vases, shall be placed on the apparatus.
DETAILED SAFETY INSTRUCTIONS:
1) Read these instructi ns.
2) Keep these instructi ns.
3) Heed all warnings.
4) F ll w all instructi ns.
5) D n t use this apparatus near water.
6) Clean nly with dry cl th.
7) D n t bl ck any ventilati n penings. Install in
acc rdance with the manufacturers instructi ns.
8) D n t install near any heat s urces such as radiat rs,
heat registers, st ves, r ther apparatus (including
amplifiers) that pr duce heat.
9) D n t defeat the safety purp se f the p larized r
gr unding-type plug. A p larized plug has tw blades
with ne wider than the ther. A gr unding type plug
has tw blades and a third gr unding pr ng. The wide
blade r the third pr ng are pr vided f r y ur safety. If
the pr vided plug d es n t fit int y ur utlet, c nsult
an electrician f r replacement f the bs lete utlet.
10) Pr tect the p wer c rd fr m being walked n r
pinched particularly at plugs, c nvenience receptacles,
and the p int where they exit fr m the apparatus.
11) Only use attachments/access ries specified by the
manufacturer.
12) Use nly with the cart, stand, trip d, bracket, r table
specified by the manufacturer, r s ld with the
apparatus. When a cart is used, use cauti n when m ving
the cart/apparatus c mbinati n t av id injury fr m
tip- ver.
13) Unplug this apparatus during lightning st rms r
when unused f r l ng peri ds f time.
14) Refer all servicing t qualified service pers nnel.
Servicing is required when the apparatus has been
damaged in any way, such as p wer supply c rd r plug
is damaged, liquid has been spilled r bjects have fallen
int the apparatus, the apparatus has been exp sed t
rain r m isture, d es n t perate n rmally, r has been
dr pped.
15) CAUTION - These service instructi ns are f r use by
qualified service pers nnel nly. T reduce the risk f
electric sh ck d n t perf rm any servicing ther than
that c ntained in the perati n instructi ns unless y u
are qualified t d s .

3
ULTRACOUSTIC ACX450/ACX900/ACX1800
TABLE OF CONTENTS
1. INTRODUCTION ......................................................... 4
1.1 Before you get started ................................................... 4
1.1.1 Shipment ............................................................... 4
1.1.2 Initial operation ...................................................... 4
1.1.3 Online registration ................................................ 4
2. CONTROL ELEMENTS AND CONNECTIONS ............. 4
2.1 Front panel ...................................................................... 4
2.2 Rear panel ...................................................................... 6
3. APPLICATIONS .......................................................... 7
3.1 Connecting options for the ACX450 .............................. 7
3.2 Extended connecting options (ACX900 and ACX1800) 7
4. SOUND PROCESSING ............................................... 8
4.1 FBQ equalizer ................................................................. 8
4.2 Digital effects processor ................................................ 8
4.3 Compressor (only in ACX1800) ..................................... 9
5. INSTALLATION ........................................................... 9
5.1 Audio connections ......................................................... 9
6. SPECIFICATIONS ..................................................... 10
7. WARRANTY .............................................................. 11
FOREWORD
Dear Customer,
Welcome to the team of
BEHRINGER users, and
thank you very much for
expressing your confi-
dence in us by pur-
chasing the BEHRINGER
ULTRACOUSTIC.
Writing this foreword
for you gives me great
pleasure, because it
represents the cul-
mination of many months
of hard work delivered
by our engineering
team to achieve a very
ambitious goal: to
present you with an
outstanding acoustic
instrument amplifier that
is at the forefront of what is technically possible and that offers
you a vast variety of sound shaping options. The task of designing
our new ULTRACOUSTICs certainly meant a great deal of
responsibility, which we assumed by focusing on you, the
discerning user and musician. Meeting your expectations also
meant a lot o6f work and night shifts. But it was fun, too.
Developing a product usually brings a lot of people together, and
what a great feeling it is when all who participated in such a
project can be proud of what theyve achieved.
It is our philosophy to share our enjoyment with you, because
you are the most important member of the BEHRINGER team.
With your highly competent suggestions for new products youve
made a significant contribution to shaping our company and making
it successful. In return, we guarantee you uncompromising quality
as well as excellent technical and audio properties at an extremely
reasonable price. All of this will enable you to give free rein to
your creativity without being hampered by budget constraints.
We are often asked how we manage to produce such high-
quality devices at such unbelievably low prices. The answer is
quite simple: its you, our customers! Many satisfied customers
mean large sales volumes enabling us to get better purchasing
terms for components, etc. Isnt it only fair to pass this benefit on
to you? Because we know that your success is our success
too!
I would like to thank all of you who have made the ULTRACOUSTIC
Series possible. You have all made your own personal
contributions, from the developers to the many other employees
at this company, and to you, the BEHRINGER user.
My friends, its been worth the effort!
Thank you very much,
Uli Behringer

4
ULTRACOUSTIC ACX450/ACX900/ACX1800
1. INTRODUCTION
Thank you for choosing the ULTRACOUSTIC amplifier. You have
purchased a modern 2-channel amplifier that guarantees
excellent sound quality for various applications yet is easy to
operate. The ULTRACOUSTIC comes with a wide range of
features such as two integrated, 24-bit multi-effect processors
or the FBQ Feedback Detection system which help you to
fine-tune your sound. Due to the many possibilities of connecting
external effects units and playback feeds, the ULTRACOUSTIC
is a real all-rounder leaving nothing to be desired.
+Please read this manual t familiarize y urself with
the c ntr l elements f the unit and its functi ns.
After y u have carefully read this manual, keep it
f r future reference.
1.1 Before you get started
1.1.1 Sh pment
The ULTRACOUSTIC was carefully packed at the assembly plant
to ensure secure transport. If the cardboard box is damaged,
please inspect the ULTRACOUSTIC equipment immediately for
physical damage.
+Damaged equipment sh uld NEVER be sent directly
t us. Please inf rm the dealer fr m wh m y u
acquired it immediately as well as the trans-
p rtati n c mpany fr m which y u t k delivery.
Otherwise, all claims f r replacement/repair may
be rendered invalid.
+If the unit needs t be shipped, please always use
the riginal packaging t av id damage.
+Never let unsupervised children play with the
ULTRACOUSTIC r with its packaging.
+Please disp se f all packaging materials in an
envir nmentally-friendly fashi n.
1.1.2 In t al operat on
Please make sure that your ULTRACOUSTIC is provided with
sufficient ventilation, and never place it on other amplifiers or in
the vicinity of a heater to avoid the risk of overheating.
+Bef re plugging y ur ULTRACOUSTIC int a p wer
s cket, please make sure y u have selected the
c rrect v ltage:
The fuse retainer near the power cord connector has three
triangular markings. Two of these triangles point in opposite
directions. Your ULTRACOUSTIC is set up for the voltage
indicated near these markings, and can be altered by turning the
fuse mount by 180 degrees. ATTENTION: This d es n t apply
t exp rt m dels built f r 120 V, f r example!
+If y u use y ur ULTRACOUSTIC unit with a different
v ltage, y u must change the fuses acc rdingly.
The c rrect value f the fuses needed can be f und
in the secti n SPECIFICATIONS.
+Faulty fuses must be replaced with fuses f
appr priate rating, with ut excepti n! The c rrect
value f the fuses needed can be f und in the
secti n SPECIFICATIONS.
Power is delivered via the cable that was delivered with the
ULTRACOUSTIC. All mandatory safety precautions have been
adhered to.
+Please make sure that all f y ur equipment is
gr unded at all times. F r y ur wn pr tecti n, y u
sh uld never tamper with the gr unding f the cable
r the unit itself. The unit shall always be c nnected
t a mains s cket utlet with a pr tective earthing
c nnecti n.
1.1.3 Onl ne reg strat on
Please, do remember to register your new BEHRINGER equipment
right after your purchase by visiting www.behringer.com and
kindly read the terms and conditions of our warranty carefully.
Should your BEHRINGER product malfunction, our goal is to have
it repaired as quickly as possible. To arrange for warranty service,
please contact the retailer from whom the equipment was
purchased. Should your BEHRINGER dealer not be located in
your vicinity, you may directly contact one of our subsidiaries.
Corresponding contact information is included in the original
equipment packaging (Global Contact Information/European
Contact Information). Should your country not be listed, please
contact the distributor nearest you. A list of distributors can be
found in the support area of our website (www.behringer.com).
Registering your purchase and equipment with us helps us
process your repair claims quicker and more efficiently.
Thank you for your cooperation!
2. CONTROL ELEMENTS
AND CONNECTIONS
2.1 Front panel
The ¼" jack connector labeled INSTR(UMENT) is the input
of the instrument channel of your ULTRACOUSTIC to
connect your acoustic guitar. Use a commercially available
mono jack cable. We recommend using a cable with impact
sound insulation so as to avoid unpleasant incidences
during a rehearsal or concert.
The PHASE switch (not included in ACX450) reverses
the instrument channel phase by 180°. Use this function
to eliminate feedback problems or phase errors of dual
pickup systems.
The GAIN controller is used to determine the volume of
the respective channel.
With the TUNER switch (not included in ACX450),
you can mute the channel. There is a permanent signal at
the TUNER connector at the rear of the unit. You
have the option to connect an external tuner to this jack
(e.g. BTR2000, TU100).
When the input signal overdrives the instrument channel,
the CLIP LED located in the TUNER switch is on (only in
ACX1800). Reduce the input gain with the GAIN controller
until the CLIP LED is off. Occasional flashing of the CLIP
LED caused by signal peaks is harmless though, as the
instrument channel has sufficient headroom.
This is the FBQ EQUALIZER. Each sliding controller
controls a specific frequency range. In position 0,
the frequency is not adjusted. To boost a frequency range,
move the respective sliding controller up. To lower its
volume, move the sliding controller down. The maximum
boosting or damping range is 12 dB.
Press the FBQ switch to activate the FBQ function. While
the FBQ is switched off, the controller LEDs are lit with
the same brightness. When the FBQ is on and you play
your instrument, the LEDs brightness varies, depending
on the energy content of the associated frequency range.
This visual feature supports you in adjusting the sound
and eliminating feedback. The equalizer is always
activated, irrespective of whether the FBQ function is on.
2. CONTROL ELEMENTS AND CONNECTIONS

5
ULTRACOUSTIC ACX450/ACX900/ACX1800
The MIC jack is the balanced XLR microphone input of the
microphone/line channel.
The balanced LINE jack (1/4") of the microphone/line
channel can be used for line-level signals, e.g. from
keyboards, drum computers, etc.
The COMPRESSOR controller is used to adjust the
intensity of the compression (only in ACX1800, see
chapter 4.3).
The compressor is switched on/off with the IN/OUT
switch (only in ACX1800).
With the FX SELECT controller, you can select one of
16 effect programs. For a detailed description of the
available effects, see table 4.1 in chapter 4.2.
With the PARAMETER controller (only in ACX1800) you
can edit certain effect parameters. For details on the
parameters that are adjustable for each effect, see
table 4.1.
The IN/OUT switch (not included in ACX450) allows you
to activate the selected effect. If an effect has been
activated, the LED in the switch is on. Alternatively, you
can switch the selected effect on and off with the foot
switch.
The FX LEVEL controller is used to adjust the level (share)
of the selected effect.
With the MASTER controller, you can adjust the overall
volume of the ACX1800.
The PHASE switch reverses the phase of the mix signal
by 180° (only in ACX1800). Use this switch to eliminate
problems with feedback.
The ULTRACOUSTIC is equipped with a CD input at the
rear panel. Use the CD LEVEL controller in the master
section (only in ACX1800) to adjust the volume of the
signal connected to the CD jack. In the ACX900 and
ACX450, this controller is located on the rear panel
(see fig. 2.2).
The CD jack of the ACX1800 can be muted with the MUTE
switch.
Use the POWER switch to switch on the ULTRACOUSTIC.
Before connecting the ULTRACOUSTIC to the power
mains, ensure that the POWER switch is in OFF position.
To disconnect the unit from the mains network, pull the
plug from the socket. When switching on the
ULTRACOUSTIC, ensure that the mains plug is easily
accessible.
+Please n te: The POWER switch d es n t fully
disc nnect the unit fr m the mains p wer c rd plug
r extenti n c rd. T disc nnect the unit fr m the
main p wer s urce, pull ut the main c rd plug r
appliance c upler. When installing the pr duct,
ensure the plug r appliance c upler is readily
perable. Unplug the p wer c rd when the unit is
n t used f r a pr l nged peri d f time.
2. CONTROL ELEMENTS AND CONNECTIONS
ACX450
ACX900
ACX1800
Fig. 2.1: T e front panel control elements

6
ULTRACOUSTIC ACX450/ACX900/ACX1800
2. CONTROL ELEMENTS AND CONNECTIONS
2.2 Rear panel
ACX450
ACX900
ACX1800
Fig. 2.2: Rear panel connectors
Use the balanced LINE outputs (XLR connections) to
connect your ULTRACOUSTIC to the inputs of a mixing
desk (only in ACX1800 and ACX900).
With the GND LIFT (ground lift) switch you can
disconnect the ground connection between the amplifier
and the mixing desk (switch pressed). This is done to
eliminate buzz or ground loop hum.
You also have the option to take up the audio signal from
the instrument channel at the TUNER output and to feed
it to the tuner. There is a continuous signal at this jack.
Connect the supplied double foot switch to the
FOOT SW(ITCH) jack. The foot switch enables you to
switch the effects of both channels on and off
(corresponds to the function of the IN/OUT switch ).
The CD IN input (RCA) allows for the connection of an
external stereo source. You can for example play your
favourite tune while being accompanied with music from
a CD, MD or a drum machine.
+ MIC INSERT: The microphone channel is equipped
with a serial loop connection for external effects units.
To do this, connect the SEND jack with the input of
your effects unit. Connect the output of the external effects
unit to the RETURN jack of the ULTRACOUSTIC.
+ INST(RUMENT) INSERT: The instrument channel is
also equipped with a serial loop connection for external
effects units. is the respective SEND connector
(output) and is the respective RETURN connector
(input).
+The INSERT SEND c nnect r can als be used as
parallel utputs, e.g. t individually feed the signal
f ne channel. As l ng as the RETURN c nnect r
is n t used, the internal signal fl w is n t
interrupted.
Fig. 2.3: Standard IEC power receptacle,
fuse older and serial number (rear panel)
Power is supplied via an IEC connector. The matching
cable is provided with the unit.
FUSE RETAINER/VOLTAGE SELECTOR: Please make
sure that the voltage indicated by the voltage selector
matches the local voltage before you connect the unit to
the main power supply. Always replace blown fuses with
fuses of the same type and rating. Some units feature a
fuse retainer in which a selection between 230 V and
120 V is possible. Please be aware: When using your unit
outside of Europe with 120 V, a fuse with a higher rating is
required.
SERIAL NUMBER.

7
ULTRACOUSTIC ACX450/ACX900/ACX1800
3. A LICATIONS
3. APPLICATIONS
3.1 Connecting options for the ACX450
Fig. 3.1: Cabling options of t e ACX450
The above cabling is suitable for sessions in the rehearsal room
or for practicing at home. Connect your guitar to the instrument
input jack of channel 1. If desired, connect another instrument or
a dynamic microphone to channel 2.
Connect the supplied FS112 foot switch to the foot switch input
at the rear panel. With the foot switch, you can switch the
effects units of both channels on and off, which is particularly
useful during live performances.
To play along with a playback, connect a CD player to the
CD input. Of course, a MD player or a computer can be used as
playback device as well.
3.2 xtended connecting options
(ACX900 and ACX1800)
Fig. 3.2: Extended connecting options
(ACX900 and ACX1800)
Models ACX900 and ACX1800 offer a wide range of additional
connecting options. The above figure shows only one of many
possible installations:
The instruments, microphones, the foot switch as well as the
CD player are connected as shown in figure 3.1. The tuner is
connected to the tuner output where there is a constant
instrument signal. If you wish to integrate external effects units,
you can do this separately for each of the two channels. Connect
the input of the effects unit to the INSERT SEND of one of the
respective channels, and connect the effect output at the unit to
the INSERT RETURN jack of the same channel. Instead of the two
stage effects units shown here connected in series in the signal
path, you can establish a parallel effects loop, e.g. by means of
a 19" studio effects unit. In this case, connect the input of the
effects unit to the MIC INSERT SEND or the INSTRUMENT INSERT
SEND output, and feed the stereo output signal of the effects
unit through the CD INPUT jacks. You can then use the CD LEVEL
controller to mix the effects signal and your guitar signal. With
this option, please note that the effects unit only returns the
effects signal (100%Wet) and not the original signal.
Musicians who wish to play their instrument through a PA system
during a live session normally need a DI box. A DI box prepares
the signal for transfer through long cable lines, so that a higher
output level for the mixing desk can be achieved. You will be
delighted to know that your ULTRACOUSTIC comes with a built-
in DI box! Connect the balanced LINE outputs directly to the mixing
desk input or to the multi-core feeding to the mixing desk.
Use a microphone cable (two-core shielded cable with
XLR connectors).

8
ULTRACOUSTIC ACX450/ACX900/ACX1800
4. SOUND ROCESSING
4. SOUND PROCESSING
The ULTRACOUSTIC offers many options for sound processing.
The ACX1800 includes, for example, an FBQ equalizer, a multi-
effects unit and a compressor. The various processing options
are explained in this chapter.
4.1 FBQ equalizer
A graphic equalizer with FBQ spectrum analyzer is available
for sound adjustment and correction. If the sliding controllers
are in neutral position (0), the signal is not modified.
sTo boost the frequency range, move the respective sliding
controller up.
sTo dampen the range, move the sliding controller down.
sPress the FBQ switch to activate the FBQ display.
FBQ function: Each controller is equipped with a LED indicating
the level of the associated frequency range of the controller by
means of its brightness. This assists you in identifying the
controller that must be used to edit the sound. If the sound is for
example too dull or too droning, one of the LEDs is probably very
bright, indicating the sliding controller that should be moved down
to reduce the bass level. On the other hand, you can quickly
identify frequency ranges whose level is too low (LED barely lit)
to increase it.
+T emphasize certain frequency ranges, it might
n t be necessary t raise these, but t l wer the
levels f the ther frequencies by m ving the
respective sliding c ntr llers d wn. This appr ach
prevents excessively high internal signal levels,
thus retaining valuable dynamic reserves
(headr m).
4.2 Digital effects processor
One of the key features of your ULTRACOUSTIC are the two
built-in multi-effects processors that operate independently of
each other in both channels. Each effects module offers a total
of 16 different programs that are grouped in four categories.
sTo switch effects on or off, press the IN/OUT switch
at the ULTRACOUSTIC or at the foot switch.
sTurn the FX SELECT controller to select a program.
The effects are described in the following overview:
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Chamber Decay

Room Decay

Hall Decay

Concert Decay

Chorus Depth

Flanger Depth

Phaser Speed

Tremolo Speed

Chorus / Delay 400 ms Delay Level

Flanger / Delay 400 ms Delay Level

Chorus / Delay 300 ms Delay Level

Flanger / Delay 300 ms Delay Level

Delay 80 ms Feedback

Delay 300 ms Feedback

Delay 400 ms Feedback

Delay 500 ms Feedback
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Table 4.1: Effects programs
sUse the FX LEVEL controller to make the effect
audible.
sEdit the effect using the PARAMETER controller
(only in ACX1800).
The reverb presets are effects that imitate the reverberation of
various large rooms. Use the PARAMETER controller to adjust
the reverberation time (decay).
1CHAMBER simulates the typical characteristics of a studio.
This effect is useful in cases where you need unobtrusive
reverb to liven up the signal.
2ROOM: Reverberation typical for rooms of medium size,
with clearly audible reverb from walls.
3HALL: Simulation of a lively large hall with considerable
echo.
4CONCERT simulates the prolonged reverb in a large concert
hall.
This group includes four modulation effects that are generated
in different ways. For each effect, you can adjust the depth and
speed of the modulation.
5CHORUS give guitar signals more depth and width.
This is achieved by means of a modulated delay of the
input signal.
6FLANGER: Popular guitar effect achieved by constant
modulation of the tone pitch.
7PHASER: The phase effect is similar to the flange, but
somewhat subtler. It is achieved by superimposing a
phase-shifted effects signal on the input signal.
8TREMOLO: Intensive variation of the volume at a preset
rate.
This group includes a number of dual effects where for example
a chorus or flanger effect is combined with a delay. In the
ACX1800, you can adjust the volume of the delay effect.
9 CHORUS/DELAY with a delay of 400 ms.
10 FLANGER/DELAY with a long delay (400 ms)
11 CHORUS/DELAY with a short delay (300 ms).
12 FLANGER/DELAY with a delay of 300 ms.
In this group you find delay effects with different delay times.
The Feedback parameter determines the number of repeats.
13 Short DELAY of 80 milliseconds (ms).
14 Medium DELAY of 300 ms.
15 DELAY of 400 ms.
16 Long DELAY of 500 ms.

9
ULTRACOUSTIC ACX450/ACX900/ACX1800
4.3 Compressor (only in ACX1800)
The compressor reduces the dynamic range of a signal. Volume
peaks are lowered, and low signals are boosted, so that the
difference between the loudest and the lowest tone of an
instrument or voice is reduced. This results in a more expressive
and homogeneous sound, and the sustain of long tones is
prolonged.
sSwitch on the compressor (ON switch ).
sTurn the COMPRESSOR controller slowly in clockwise
direction to increase the compression intensity.
sCompare the compressed and the original signal by
switching the compression ON and OFF (at the ON
switch).
If the input signal to the compressor is high, it operates at its
optimum range. If the signal is low, the effect becomes only
audible when the compressor controller is set to a very high
position. If a compressor is switched on in this position, there is
a risk of sudden level changes. If GAIN is set to a high value,
the same compressor effect is achievable without having to
set the controller to a high value. In this case, the COMPRESSOR
controller does not have to be turned to a position near the stop
in order to achieve any effect. We recommend that you try this
out until you have found the best settings!
5. INSTALLATION
5. INSTALLATION
5.1 Audio connections
With the exception of the balanced LINE jack mono input, all
inputs and outputs of the BEHRINGER ULTRACOUSTIC are
unbalanced mono jack sockets. The LINE OUT connections are
designed as balanced XLR outputs. The CD inputs are designed
as RCA connectors.
+Please ensure that nly qualified pers ns install
and perate the ULTRACOUSTIC. During installati n
and perati n, pers ns handling and using the
equipment must be sufficiently earthed, as
electr static discharge might affect the perati n
f the ULTRACOUSTIC!
Fig. 5.1: XLR connectors
Fig. 5.2: ¼" stereo TRS connector
Fig. 5.3: ¼" TS connector

10
ULTRACOUSTIC ACX450/ACX900/ACX1800
6. S ECIFICATIONS
6. SPECIFICATIONS
$&; $&; $&;
INSTRUMENT IN
Input Impedance
MIC IN
Input Impedance
LINE IN
Input Impedance
INST INSERT RETURN -
Input Impedance -
MIC INSERT RETURN -
Input Impedance -
CD input
Input Impedance
LINE OUT -
Output Impedance -
Max. output level -
INST INSERT SEND -
Output Impedance -
Max. output level -
MIC INSERT SEND -
Output Impedance -
Max. output level -
TUNER OUT -
Output impedance -
Max. output level -
Power rating 1 x 45 W / 4
: 2 x 45 W / 2 x 4 : 2 x 90 / 2 x 4 :
Converters
Sampling rate
Type 1 x 8" 2 x 8" 2 x 8"
Model
Impedance 4 Ohm 4 Ohm 4 Ohm
Power handling 40 W 60 W 60 W
Power consumption max. 90 W max. 135 W max. 265 W
Fuses 100 - 120 V~
7$+ 250 V 7$+ 250 V 7$+ 250 V
Fuses 200 - 240 V~
7$+ 250 V 7$+ 250 V 7$+ 250 V
Mains connection
413 x455 x 212 mm 423 x 526 x 232 mm 427 x 526 x 242 mm
16.3 x 17.9 x 8.3" 16.7 x 20.7 x 9.1" 16.8 x 20.7 x 9.5"
Weight 29.1 lbs (13.2 kg) 37 lbs (16.8 kg) 40.6 lbs (18.4 kg)
',0(16,216$1':(,*+7
$8',2,13876
$8',22873876
6<67(063(&,),&$7,216
',*,7$/352&(66,1*
Standard IEC receptacle
>18 dBu
¼" TS unbalanced
33 kOhm
>6 dBu
Dimensions
(H x W x D)
24-bit sigma-delta, 64/128-times oversampling
40 kHz
BUGERA™ dual cone speakers
Mains voltage
USA/Canada 120 V~, 60 Hz
Europe/U.K./Australia 230 V~, 50 Hz
Japan 100 V~, 50 - 60 Hz
China/Korea 220 V~, 50 Hz
General Export model 120/230 V~, 50 - 60 Hz
/28'63($.(56
32:(56833/<
100 Ohm
>18 dBu
¼" TS unbalanced
100 Ohm
XLR balanced
4.3 kOhm
>24 dBu
¼" TS unbalanced
¼" TS unbalanced
220 kOhm
RCA
>10 kOhm
¼" TRS balanced
40 kOhm
¼" TS unbalanced
220 kOhm
¼" TS unbalanced
10 MOhm
XLR balanced
4 kOhm
BEHRINGER is constantly striving to maintain the highest professional standards. As a result of these efforts, modifications may be made
from time to time to e isting products without prior notice. Specifications and appearance may differ from those listed or illustrated.

11
ULTRACOUSTIC ACX450/ACX900/ACX1800
7. WARRANTY
7. WARRANTY
§ 1 OTHER WARRANTY RIGHTS AND NATIONAL LAW
1. This warranty does not exclude or limit the buyers statutory
rights provided by national law, in particular, any such rights against
the seller that arise from a legally effective purchase contract.
2. The warranty regulations mentioned herein are applicable
unless they constitute an infringement of national warranty law.
§ 2 ONLINE REGISTRATION
Please do remember to register your new BEHRINGER equipment
right after your purchase by visiting www.behringer.com
(alternatively www.behringer.de) and kindly read the terms and
conditions of our warranty carefully. Registering your purchase
and equipment with us helps us process your repair claims
quicker and more efficiently. Thank you for your cooperation!
§ 3 WARRANTY
1. BEHRINGER (BEHRINGER International GmbH including all
BEHRINGER subsidiaries listed on the enclosed page, except
BEHRINGER Japan) warrants the mechanical and electronic
components of this product to be free of defects in material and
workmanship for a period of one (1) year* from the original date
of purchase, in accordance with the warranty regulations
described below. If the product shows any defects within the
specified warranty period that are not excluded from this
warranty as described under § 5, BEHRINGER shall, at its
discretion, either replace or repair the product using suitable new
or reconditioned parts. In the case that other parts are used which
constitute an improvement, BEHRINGER may, at its discretion,
charge the customer for the additional cost of these parts.
2. If the warranty claim proves to be justified, the product will be
returned to the user freight prepaid.
3. Warranty claims other than those indicated above are expressly
excluded.
§ 4 RETURN AUTHORIZATION NUMBER
1. To obtain warranty service, the buyer (or his authorized dealer)
must call BEHRINGER (see enclosed list) during normal business
hours BEFORE returning the product. All inquiries must be
accompanied by a description of the problem. BEHRINGER will
then issue a return authorization number.
2. Subsequently, the product must be returned in its original
shipping carton, together with the return authorization number to
the address indicated by BEHRINGER.
3. Shipments without freight prepaid will not be accepted.
§ 5 WARRANTY REGULATIONS
1. Warranty services will be furnished only if the product is
accompanied by a copy of the original retail dealers invoice.
Any product deemed eligible for repair or replacement under the
terms of this warranty will be repaired or replaced.
2. If the product needs to be modified or adapted in order to
comply with applicable technical or safety standards on a national
or local level, in any country which is not the country for which
the product was originally developed and manufactured, this
modification/adaptation shall not be considered a defect in
materials or workmanship. The warranty does not cover any
such modification/adaptation, irrespective of whether it was
carried out properly or not. Under the terms of this warranty,
BEHRINGER shall not be held responsible for any cost resulting
from such a modification/adaptation.
3. Free inspections and maintenance/repair work are expressly
excluded from this warranty, in particular, if caused by improper
handling of the product by the user. This also applies to defects
caused by normal wear and tear, in particular, of faders,
crossfaders, potentiometers, keys/buttons, tubes, guitar strings,
illuminants and similar parts.
4. Damages/defects caused by the following conditions are not
covered by this warranty:
simproper handling, neglect or failure to operate the unit in
compliance with the instructions given in BEHRINGER user
or service manuals.
sconnection or operation of the unit in any way that does
not comply with the technical or safety regulations applicable
in the country where the product is used.
sdamages/defects caused by force majeure or any other
condition that is beyond the control of BEHRINGER.
5. Any repair or opening of the unit carried out by unauthorized
personnel (user included) will void the warranty.
6. If an inspection of the product by BEHRINGER shows that the
defect in question is not covered by the warranty, the inspection
costs are payable by the customer.
7. Products which do not meet the terms of this warranty will be
repaired exclusively at the buyers expense. BEHRINGER will
inform the buyer of any such circumstance. If the buyer fails to
submit a written repair order within 6 weeks after notification,
BEHRINGER will return the unit C.O.D. with a separate invoice
for freight and packing. Such costs will also be invoiced
separately when the buyer has sent in a written repair order.
§ 6 WARRANTY TRANSFERABILITY
This warranty is extended exclusively to the original buyer
(customer of retail dealer) and is not transferable to anyone
who may subsequently purchase this product. No other person
(retail dealer, etc.) shall be entitled to give any warranty promise
on behalf of BEHRINGER.
§ 7 CLAIM FOR DAMAGES
Failure of BEHRINGER to provide proper warranty service shall
not entitle the buyer to claim (consequential) damages. In no
event shall the liability of BEHRINGER exceed the invoiced value
of the product.
* Customers in the European Union please contact BEHRINGER
Germany Support for further details.
Technical specifications and appearance subject to change without notice. The information contained herein is correct at the time of
printing. The names of companies, institutions or publications pictured or mentioned and their respective logos are registered
trademarks of their respective owners. Their use neither constitutes a claim of the trademarks by BEHRINGER nor affiliation of the
trademark owners with BEHRINGER. BEHRINGER accepts no liability for any loss which may be suffered by any person who relies
either wholly or in part upon any description, photograph or statement contained herein. Colours and specification may vary slightly
from product. Products are sold through our authorised dealers only. Distributors and dealers are not agents of BEHRINGER and have
absolutely no authority to bind BEHRINGER by any express or implied undertaking or representation. No part of this manual may be
reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording of any kind,
for any purpose, without the express written permission of BEHRINGER Spezielle Studiotechnik GmbH. BEHRINGER® is a registered
trademark.
ALL RIGHTS RESERVED. © 2006 BEHRINGER Spezielle Studiotechnik GmbH,
Hanns-Martin-Schleyer-Str. 36-38, 47877 Willich-Muenchheide II, Germany.
Tel. [phone], Fax [phone]

FEDERAL COMMUNICATIONS
COMMISSION COMPLIANCE
INFORMATION
Responsible party name: MUSIC Group Services USA, Inc.
Address: 18912 North Creek Parkway,
Suite 200 Bothell, WA 98011,
USA
Phone/Fax No.: Phone: [phone]
Fax: [phone]
ULTRACOUSTIC ACX450/ACX900/ACX1800
complies with the FCC rules as mentioned in the following paragraph:
This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to part 15 of the FCC Rules. These limits are designed
to provide reasonable protection against harmful interference in a residential
installation. This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the instructions, may cause
harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause
harmful interference to radio or television reception, which can be determined
by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
Reorient or relocate the receiving antenna.•
Increase the separation between the equipment and receiver.•
Connect the equipment into an outlet on a circuit different from that to which the•
receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.•
This device complies with Part 15 of the FCC rules. Operation is subject to the
following two conditions:
(1) this device may not cause harmful interference, and
(2) this device must accept any interference received, including interference that may
cause undesired operation.
Important information:
Changes or modifications to the equipment not expressly approved by MUSIC Group
can void the user’s authority to use the equipment.
ULTRACOUSTIC
ACX450/ACX900/ACX1800
behringer.com