Acoustic Energy Loudspeaker Linear Subwoofer User Manual

							O W N E R ’ S   M A N U A L 
						

							Page Section
 1 Introduction
 2 Handling
1 3 Installation
1 4 Positioning
2 5 Connecting
3 6 Controls and System Setup
4 7 Specification
5 8 The Linear Range
5 9 Warranty
5 10 Contact Acoustic Energy
3 .   I n s t a l l a t i o n
Welcome to the Linear Sub. Perhaps more than 
any other hi-fi product, speakers are sensitive to 
installation so please take a little time to read 
this manual and to follow, as far as practical, 
the installation guidelines it contains. Careful 
installation will help ensure that your Linear Sub 
performs optimally. Should you have any questions 
not covered here we are happy to try and answer 
them either by telephone or email. Contact 
information can be found in Section 11.
Following this introduction, the Manual is divided 
into sections covering handling, installation, 
positioning, connecting, controls and system setup, 
specifications, matching products, warranty and 
contact information. We recommend that you read 
at least the first six of these sections carefully before 
installing and using your Linear Sub. We would 
also draw your attention to the Important Safety 
Instructions on this page.
Finally, please enjoy your Linear Sub, but remember 
it is capable of generating high volume levels of 
low frequency sound, so please also be considerate 
of your neighbours.
The Linear Sub is a relatively delicate precision 
engineered product that can be damaged by 
inappropriate handling. It is also large and heavy. 
Please take great care therefore when unpacking 
or moving it. Plan any handling in advance of 
carrying it out - ideally with a second person to 
help. Please take care when unpacking or moving 
the subwoofer not to touch any of the drivers. 
Damage to a driver will at best degrade the 
Linear Sub’s performance and at worst result in its 
complete failure.
The enclosure surfaces should also be handled 
sympathetically. Any cleaning should only require a 
soft cloth, slightly dampened if necessary. Be wary 
of using any polishes or solvent based cleaning 
agents.
The packaging should be retained for future use.
C o n t e n t s
Important Safety Instructions
Ensure that your Linear Sub is set to the appropriate mains input voltage before it is connected to a mains socket. The warranty does not cover damage caused by incorrect mains voltage.
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with dry cloth.
7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
9. Do not defeat the safety purpose of the grounding-type plug. A grounding type plug has two blades and a third grounding prong. The third prong is provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.
10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus. When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
13. Unplug this apparatus during lightning storms or when unused for long periods of time.
14. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
15. The apparatus shall not be exposed to dripping or splashing and that no objects filled with liquids, such as vases, shall be placed on the apparatus.
16. The MAINS plug is used as the disconnect device, the disconnect device shall remain readily operable.
17. To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture.
1 .   I n t r o d u c t i o n
2 .   H a n d l i n g 
						

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3 .   I n s t a l l a t i o n
The Linear Sub is intended to be used in either 
stereo audio music systems or multi-channel 
audio-visual (home theatre) systems. Although it is 
intended primarily to partner other products in the 
Linear range it may also be used successfully with 
alternative loudspeakers.
Linear Sub must be fitted with either floor spikes or 
rubber feet. Floor spikes offer the highest potential 
performance and should be fitted if the subwoofer 
is to be placed on a carpeted floor. If spikes are 
inappropriate for your floor covering, metal 
protection pads, coins for example, maybe used 
between the spike and the floor.
Note: Damage to the drive unit may result if Linear 
Sub is placed upright on the floor without floor 
spikes or feet fitted.
The rubber feet or M8 floor spikes and lock-nuts 
should be fitted to the underside of the subwoofer 
once it has been moved near its final location. 
Carefully lay the subwoofer on its side to gain 
access to the tapped holes in the underside. If 
the rubber feet are to be used simply screw them 
into the tapped holes and return the subwoofer to 
upright. If floor spikes are to be used screw a spike 
and lock-nut into each hole leaving a length of 
C o n t e n t s
1 .   I n t r o d u c t i o n
2 .   H a n d l i n g
spike extending beyond the lock-nut such that once the subwoofer is upright 
the lock-nuts will “float” just above the floor covering.
Tighten three of the lock-nuts with a 13mm spanner leaving one lock-nut 
finger-tight to aid adjustment once the subwoofer is upright in its final 
position. Once the final position has been established adjust the length of the 
loose spike such that the subwoofer is vertical and does not rock. If the floor is 
particularly uneven it may be necessary to loosen one of the tightened spikes 
to ensure that the subwoofer can be levelled.
Finally, tighten all loose lock-nuts. It may be necessary to re-adjust to minimise 
rock once the subwoofer has settled on the floor. Take care when installing 
floor spikes. They are sharp and can cause injury or pierce electrical cables.
Linear Sub is not magnetically shielded and may cause picture distortion if 
located too close to a CRT screen. Contact your dealer installer or Acoustic 
Energy for advice.
4 .   P o s i t i o n i n g
The position of the speakers in a home theatre installation will have great 
influence over its performance. It is worth spending some time experimenting 
both with the finer points of speaker positioning, as well as the larger scale 
issues of room layout. Diagram One over the page illustrates an idealised 
general home theatre speaker layout.
If you are already familiar with the characteristics of your room, and the way 
speakers perform in it, you may already have a good feel for where to position 
your Linear Sub. However, installing any new component provides a good 
opportunity to review an existing set-up and perhaps make improvements.
In principle there is great freedom of position of a sub-woofer in a listening 
room. In practice, however, the performance will be fundamentally influenced 
by the room and position. Small changes of location, or of the acoustic 
character of items in the immediate vicinity of the subwoofer, can significantly 
influence its performance.
Initially choose a site for the Linear Sub along one of the walls of the listening 
room well away, but not equi-distant, from the corners. It is not necessary that 
the Linear Sub be positioned along the same wall as the main loudspeakers. 
Chose a solid wall (rather than a partition) and keep the subwoofer clear of 
any large resonant objects - furniture panels, heating radiators, etc.
Don’t worry if, thanks to the architecture or layout of your room, it is not 
practical to follow these guidelines exactly. The most important thing is to 
experiment with the different options that are practical and find the best one.
Once your Linear Sub is connected and working, and you begin to become 
familiar with its performance, it is likely to be worthwhile experimenting a 
little more with its positioning. For example, moving the Linear Sub towards a 
room corner will increase the level of low bass. This gain may however be at 
the expense of bass definition and consistency over the listening area. 
						

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D i a g r a m   O n e6 .   C o n t r o l s   &   S y s t e m   S e t u p
The Linear Sub requires 
connection both to mains power 
and an appropriate audio signal. 
The connection sockets are located 
on the back panel illustrated 
opposite. Leave the subwoofer 
switched-off at the mains until all 
connections are made and ensure 
that the subwoofer level control, 
also located on the back panel 
is turned fully anti-clockwise. 
Connecting your Linear Sub 
to an audio signal is a simple 
process, however, there are some 
choices to be made concerning 
connection mode.
Signal Input Connections
Linear Sub is fitted with both line-
level and high level inputs.
The RCA Phono socket line level 
inputs are intended to accept 
signals from either audio-visual 
processors or stereo preamplifiers 
(or integrated amplifiers incorporating preamplifier 
outputs). Connect to these input sockets using an 
appropriate RCA Phono connection cable. Ensure 
that the cable is of good quality. If connecting from 
a stereo amplifier, connect the left output to the 
left input and the right output to the right input. 
If connecting from an audio visual processor the 
single subwoofer output may be connected to 
either left or right input.
The binding-post high level inputs are intended 
to be used in conventional stereo systems where 
the Linear Sub is to augment the low frequency 
performance of a pair full range speakers, and 
where no appropriate line-level signal is available. 
Connect using simple twin core cable from either 
the amplifier’s speaker terminals or from the full-
range speaker terminals themselves. Take care not 
to reverse the polarity of any connections (connect 
positive to positive and negative to negative) or 
any left/right orientation (connect left to left and 
right to right). The binding posts will accept either 
“4mm” plugs or stripped wires. Take care if using 
stripped wires not to “short” the amplifier by 
unintentionally connecting stray wires.
Note: An alternative high level input connections 
scheme is to connect from the stereo amplifier to 
the subwoofer high level inputs and then from the 
subwoofer high level outputs (see the following 
paragraph) to the full-range speakers. This scheme 
however both demands longer lengths of high 
quality speaker cable and introduces unnecessary 
connections between the amplifier and full-range 
speakers.
Signal Output Connections
Line level and high level signal output connections 
are also fitted to the Linear Sub rear panel. Both 
carry an output signal identical to the input signal 
and may be used for example to transfer the 
signal back to a power amplifier or to multiple 
subwoofers.
Mains Connection
After checking that the mains voltage specified on 
the subwoofer rear panel is set correctly, connect 
the subwoofer via its IEC mains input to a mains 
wall socket. Use only the mains cable supplied with 
the subwoofer.
LeftFront
Viewing/listening position
RightFrontCentre
LeftSurroundRightSurround
Alternative or Extra LeftSurround
Alternative or Extra RightSurround
Sub-woofer
5 .   C o n n e c t i n g 
						

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D i a g r a m   O n e6 .   C o n t r o l s   &   S y s t e m   S e t u p
Subwoofer Controls
Accompanying the mains and signal input sockets 
on the subwoofer connection panel are a level 
control, a crossover frequency control, an auto 
power switch and a phase reversal switch. Their 
function and use is described in the following 
paragraphs.
Subwoofer Level
The level control adjusts the volume of the 
subwoofer relative to the satellites. Begin with 
the level control set to around 50%. Detailed 
subwoofer adjustment guidelines can be found in 
the following paragraphs.
Subwoofer Crossover Frequency
The crossover frequency control adjusts the upper 
frequency at which the subwoofer output is filtered 
for the full-range speakers to take over. If the Linear 
Sub is to be used exclusively in an audio-visual 
system the crossover frequency should be set at 
80Hz.
If the Linear Sub is to augment the low frequency 
performance of a pair full range speakers, the 
crossover frequency should be set to match their 
low frequency roll-off frequency. The larger the 
speaker, the lower its low frequency roll-off will be. Finding the optimal 
crossover frequency setting will require experiment and adjustment, but 
reasonable initial values for different speaker types are as follows:
Large floor stand speaker (Linear 3): 35Hz
Medium stand mount loudspeakers: 50Hz
Small stand mount speakers (Linear 1): 70Hz
Subwoofer Phase
The phase switch reverses the subwoofer acoustic polarity. With the switch 
set to 0° the subwoofer output is in phase with the full range speakers. With 
the switch set to 180° the subwoofer output is out of phase. Reversing the 
subwoofer phase can help optimise the sound of subwoofer systems. Further 
subwoofer phase advice can be found below.
Subwoofer Auto Power
The subwoofer mains power switch incorporates an automatic switch-on/
off function. With the switch set to “Auto” the subwoofer will switch on 
automatically when an audio signal is present. It will switch off again when 
no signal has been present for around 10 minutes. With “on” selected the 
subwoofer remains switched-on permanently.
Note: There is necessarily a short delay between auto switch-on and audible 
sound from the subwoofer.
System Setup
Before listening to your system make one final check of the cables and 
connections. If all appears well begin listening at a relatively low volume to 
confirm that the system is operating as expected. Only increase the volume 
if you are happy that the sound at low volume is fundamentally as expected. 
If you are unhappy, turn the system off and re-check all the cables and 
connections.
The Linear Sub may take a little time to reach normal operating temperatures 
and to “run-in”. Your ears too will take some time to adjust to the new 
sound, so it is unwise therefore to make rapid judgements about the 
performance of the system.
The most important aspect of Linear Sub setup is its integration with the 
full-range speakers. Assuming the locations chosen for these are satisfactory, 
adjusting the subwoofer’s location in the room, its volume level and phase, 
and, if it is used in a conventional stereo system, its the crossover frequency, 
should enable a good end result to be achieved.
Select a few short examples of familiar programme material - both movie and 
music - to use while adjusting the setup. Listen also from a variety of different 
positions in the room. Check for balance and consistency of sound - neither 
too much nor too little bass across the range of programme material and 
listening positions. Experimentation and careful listening is the key to finding 
a good subwoofer setup. 
						

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6 .   C o n t r o l s   &   S y s t e m   S e t u p8 .   T h e   L i n e a r   R a n g e
7 .   S p e c i f i c a t i o n
Type: Closed box, active subwoofer.
Drivers: Downward facing 220mm pulp cone with 
48mm thermally bonded voice coil. High-power 
long-throw magnet system.
Low Frequency Cut-off: - 6dB @ 30Hz
Amplifier: 200 Watts into 8 Ohms
Low Pass Filter: 2nd order, 35Hz to 80Hz
Input Sensitivity: 300mv for rated output
Dimensions (H x W x D): 497 x 430 x 390mm 
Weight: 26.0kg (single, unpacked)
Acoustic Energy reserves the right to modify 
product specifications.
Subwoofer Crossover Frequency
As you adjust other parameters you may find that moving the crossover 
frequency a little from the suggested starting value is beneficial. Adjust 
other aspects of the setup, particularly subwoofer location and phase, before 
adjusting the crossover frequency significantly.
Sub-woofer Volume
Setting the subwoofer volume is important in terms of both overall system 
balance and the demands of different types of programme material. You 
may find that material with an emphasis on music works better with a lower 
subwoofer volume than movie material with an emphasis on “effects”. 
Finding a compromise between the two is a matter of subwoofer volume 
adjustment in parallel with adjusting its position in the room.
Sub-woofer Location
Broadly speaking, the closer a subwoofer is to the corner of the room 
(assuming the walls are solid) the more bass it will generate in the room (and 
the lower its volume need be set). Moving the subwoofer closer to a corner 
however will also tend to reduce the consistency subwoofer volume over the 
listening room (a corner location being the worst in this respect). Positions 
closer to the corner will also tend to change the character of the bass 
produced by the subwoofer - it will emphasise the very lowest signals more. 
This change in bass character with location is the variable that enables a good 
compromise position for the subwoofer to be found.
Sub-woofer Phase
Switching the subwoofer phase should be left to last. If a good subwoofer 
position is proving difficult to find, try again with the phase reversed. 
						

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6 .   C o n t r o l s   &   S y s t e m   S e t u p8 .   T h e   L i n e a r   R a n g e
7 .   S p e c i f i c a t i o n
9 .   W a r r a n t y
1 0 .   C o n t a c t
The Linear Sub is part of a range that includes the 
Linear One stand-mount speaker, the Linear Three 
floor-stand speaker and the Linear Centre centre 
channel speaker. Linear One, Linear Three and 
Linear Centre incorporate time-aligned drivers to 
improve image quality, depth and focus.
Linear One
Linear One is a compact two-way stand-mount 
speaker that adds high resolution accuracy to the 
imaging benefits of time alignment.
Linear Three
Linear Three is a true three-way floor stand speaker 
that builds on the performance of the Linear One 
with wider bandwidth, higher power handling and 
enhanced detail resolution.
Linear Centre
Linear Centre is a centre channel speaker designed 
to combine with the Linear One or Three for 
perfectly matched audio-visual systems.
Your Acoustic Energy speakers are guaranteed against original defects in 
materials, manufacture and workmanship for 3 years from the date of 
purchase.
Under this warranty Acoustic Energy agrees to repair any defect or, at the 
company’s discretion, replace the faulty component(s) without charge for 
parts or labour. This warranty does not imply any acceptance by Acoustic 
Energy or its agents for consequential loss or damage and specifically 
excludes fair wear and tear, accident, misuse or unauthorised modification.
This warranty is applicable in the United Kingdom only and does not in any 
way limit the customer’s legal rights. Claims and enquiries under the warranty 
for Acoustic Energy products purchased outside the UK should be addressed 
to the local importers or distributors. If you have reason to claim under the 
warranty please contact your dealer in the first instance.
Please retain all original packaging materials for possible future use. We 
suggest that you complete details of purchase now and keep this information 
in a safe place for future reference.
Name:
Address:
Dealer:
Purchase Date:
Serial Numbers:
Acoustic Energy Limited
16 Bridge Road
Cirencester
Gloucestershire GL7 1NJ
UK
Tel:  +44 (0)1285 654432 (Sales)
 +44 (0)1285 656890 (Technical)
Fax:  +44 (0)1285 654430
Email: [email protected]
Web:  www.acoustic-energy.co.uk 
						

							Acoustic Energy Limited, 16 Bridge Road, Cirencester, Gloucestershire GL7 1NJ.
Tel: +44 (0)1285 654432 (Sales), +44 (0)1285 656890 (Technical). Fax: +44 (0)1285 654430
Email: [email protected]
Web: www.acoustic-energy.co.uk
Manual Part No. MA1108