At PMC, we believe that music is what really matters; it’s
what moves us and gives us the passion for what we do.
It’s relatively easy to create loudspeakers that colour or atter music
— but that has never been our way. The quest for sonic neutrality and
transparency has always been PMC’s obsession, using advanced
engineering to reproduce music as vividly and faithfully as possible. Our
designs are involved in every stage of music-making, from the recording
studio to listening at home. From this experience, we know exactly how
to present music as transparently as possible, just as the artist intended.
As we like to say, loudspeakers are where science meets art — we take
care of the science so you can connect with the art.
Oliver Thomas, Chief Technical Ofcer
Peter Thomas, Owner &
CONGRATULATIONS
– YOU HAVE JOINED THE ELITE
Stevie Wonder
ESPN
BBC
Tony Bennett
Apple
EMI
SONY
Coldplay
You have joined the elite. You’re a
PMC user.
Our loudspeakers can be found in all
the world’s best listening environments,
from audiophile living rooms to
internationally renowned recording,
mastering, broadcast and post-
production studios. Our Emmy-award-
winning systems are used to create
everything from smash Hollywood
soundtracks to hit albums by artists
including Coldplay, Kraftwerk, Elton
John and Adele, as well as audiophile
jazz and classical recordings on
Deutsche Grammophon, Decca,
Philips and Harmonia Mundi.
Whether you listen to our speakers in
world-class studios in LA, London, Berlin
or Tokyo, or in your favourite listening
room at home, you will hear the music
exactly as the artist intended it.
UNIVERSAL MUSIC GROUP
Thomas Newman
Afrojack
Kraftwerk
Royal College of Music
Warner Music
Pinewood Studios
Capit Studios
elbow
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CONTENTS
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General usage guidelines
TM
PMC’s ATL
Laminair
Our meticulous attention to detail
Unpacking
Installing the resonance-absorbing plinth bars
Dedicated twenty5i series stands
Connections - plugging them in
Running in or breaking in
Positioning
Fine tuning for perfect bass
Stereo set up
Surround sound specic set up
Ideal 5.1 surround sound set up
(Advanced Transmission Line)
TM
Ideal 7.1 surround sound set up
Service
Specications
Warranty on-line
Warranty certicate – Part 1 – Your copy
Warranty certicate – Part 2 – Our copy
Help us improve – Your comments
Inspection certicate
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GENERAL USAGE GUIDELINES
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Read these instructions and keep them in a safe place for future reference.
Heed all electrical safety warnings, including any on the loudspeakers themselves.
Do not use the loudspeakers near water.
The cabinet should only be cleaned with a dry, lint-free, cloth. Do not use solvents,
abrasives, waxes or liquids as they may be detrimental to the nish.
Four soft, self-adhesive feet are included with the twenty5.Ci. These can be
attached to the base of the unit to provide vibration-free operation.
Floor spikes are sharp; treat with great care during installation and use.
Do not install near any heat sources such as radiators, ovens or other equipment
that produce excessive heat.
Unplug this product from both source and power during electrical storms, or when
unused for extended periods of time.
Packing material can pose danger to the young and vulnerable. Ensure these
items are kept or disposed of safely.
High volume audio signals, however short their duration, have the potential to
cause hearing damage. Use care when setting the system volume level to ensure
playback sound pressure levels remain within safe comfortable limits.
Do not attempt to service the equipment. There are no user serviceable parts
inside. Please refer all servicing to PMC authorised personnel.
Servicing is required when the apparatus is damaged, exposed to moisture,
or exhibits a distinct or sudden change of operation or audio performance.
PMC has made efforts to provide accurate installation information and good
quality xings. PMC will not be held responsible or liable for injuries or property
damage – direct, indirect or consequential – arising out of use or inability to use
this product safely and properly.
twenty5i loudspeakers contain very powerful magnets and therefore may have
a detrimental effect if left in close proximity to magnetically sensitive items.
Do not use the Laminair vent as a grip to lift the loudspeaker as this may result in
damage.
TM
Advanced Transmission Line
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The source of PMC’s legendary natural and wholly
realistic sound is the Advanced Transmission Line
(ATLTM) bass-loading technology.
ATLTM is an ingenious design which uses energy
generated by the bass unit in a much more
intelligent and efcient way than speaker designs
based on ported or sealed boxes.
In ATLTM loudspeakers, the highly braced cabinet
is lined with a multitude of custom-designed
acoustic materials that absorb all but the very
lowest frequencies. These are guided to exit from
a vent on the front-panel, extending the low-
frequency response and creating the impression
of a far larger speaker with an extra, ultra-high
quality bass unit.
TM
improves more than just the bass response:
ATL
because the low end is clean and clear it doesn’t
mask the rest of the music. Vocals in particular,
are beautifully projected and ultra-vivid.
ATLTM loudspeakers offer another benet. The ATLTM
bass extension does not change with volume
level – so even when listening quietly the bass
sounds balanced and well dened.
This cross-sectional view of the twenty5.24i
loudspeaker shows the ATL
arrangement and the unique Laminair
TM
cabinet
TM
vents
Our loudspeaker performance has been taken to
the next level with the addition of the Laminair
aerodynamic vent.
The ATLTM design involves air moving under pressure
at high speeds, and PMC’s Head of Design, Oliver
Thomas was able to apply aerodynamic principles
transferred from his previous industry, Formula 1 to
the ATLTM concept.
The result is the unique LaminairTMaerodynamic
vent which creates an even smoother, laminar
airow at the exit from the transmission line.
This innovative solution reduces turbulence
and drag at the ATLTM vent, reducing resistance,
increasing efciency, eliminating air noise, and
provides bass with supreme timing and the
ultimate dynamic range.
TM
‘Nothing else comes close to the
clarity, timing, and dynamics.’
OUR METICULOUS ATTENTION TO DETAIL
All PMC loudspeakers are designed and hand-built in the U.K. using individual
components that are matched to our reference model; this includes the structural
integrity of every cabinet and the testing and recording of each component.
This guarantees it will be within our strict tolerances and ensures your purchase
sounds identical to the original design. Each completed loudspeaker then
undergoes a set of objective and subjective measurements - frequency response
sweeps ensure that the design meets our exacting performance criteria, and
then listening tests are conducted against the reference model using a wide
variety of material, from a benchmark BBC speech test to classical music,
pop and rock.
Computers don’t tell the full story. As well as a
full frequency analysis, we listen to each speaker
we make and run a benchmark BBC speech and
music test on every single one.
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UNPACKING
!
Please retain your packaging for future use as all PMC
cartons are durable, reusable and can be employed
to safely transport your loudspeakers should they be
relocated or returned for servicing.
Much of the packing is constructed from recyclable
materials, so if you are to dispose of it please do so in an
environmentally friendly manner.
Packing materials can pose danger to animals, the
young and vulnerable. Ensure these items are kept or
disposed of safely.
TAKE CARE WHEN UNPACKING – THERE ARE DELICATE
TERMINALS ON THE REAR OF THE CABINET
Re-packing
When re-packing all twenty5i series
models ensure the grilles are in their
protective bags and attached to
the cabinet.
STEADY THE LOUDSPEAKER CABINET WHILE REMOVING THE CARTON
Re-packing
When re-packing all twenty5i
series models ensure the grilles
are in their protective bags and
attached to the cabinet.
TAKE CARE WHEN UNPACKING – THERE ARE DELICATE
TERMINALS ON THE REAR OF THE CABINET
INSTALLING THE RESONANCE-ABSORBING
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PLINTH BARS
Plinth bars and spikes are provided to enhance performance and stability. They
attach to the base of each speaker using M8 bolts and are isolated from both the
cabinet and oor by isolator rings of a very specic compliance.
Ensure isolator rings are placed in the rebates in the plinth bars.
Place an isolator ring over each mounting hole on the base of the cabinet.
Place the plinth bars on the speaker ensuring all the holes are aligned and
ready to take the M8 bolts.
Locate the M8 bolts and tighten them gently using the Allen/hex key provided
until they are seated but not tightened.
Once the bolts are all seated, tighten each bolt carefully by half a turn. Do not
over-tighten the bolts. Over-tightening will reduce the effect of the resonance-
absorbing material and the performance of the speaker.
Fully thread each spike through the plinth bar. The spikes can then be attached
to the plinth; they should point upwards whilst the cabinet is inverted.
Re-invert the loudspeaker so that the spikes and plinth bars are at the bottom.
Once in position, level the loudspeaker by adjusting each spike in turn.
Caution: The spikes are sharp, treat
them with care; they may damage
hard ooring if in direct contact.
We have included pucks to protect
sensitive or hard ooring.
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DEDICATED STANDS
The twenty5i series compact models are designed
to offer exceptional clarity while taking up minimal
space, and can be used either on stands or within
audio/video furniture.
However, they will realise their optimum
performance when used in conjunction with PMC’s
dedicated high-mass stand that positions them at
the ideal height and with complete stability.
Stand Features
• Unique, damped, 3-layer sandwich construction.
• Mass ll-able – sand or shot.
• Built-in cable management.
• Essential to complete the dynamic twenty5i series look.
Stand Dimensions
H 599mm +25mm spikes
W 229mm
D 364mm
CONNECTIONS
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Plugging them in
Caution
To avoid potential damage, please ensure that your power amplier(s) or
receiver is turned off before connecting or disconnecting your loudspeakers.
Cable & connectors
When selecting cables for use with your twenty5i
that their construction is of a high enough standard to withstand the rigors of
everyday use and that they are suitably terminated. While bare wire can be
accommodated by the twenty5iseries binding posts, we recommend the use
of either spade lugs or 4mm ‘banana’ plugs in order to maintain an electrical
connection of the highest integrity and avoid the possibility of short circuits.
Please consult your dealer for more information regarding cable lengths and
termination options.
series loudspeakers, ensure
Do not use tools to tighten the binding posts
Polarity + &
It is of vital importance to observe the polarity markings and maintain
positive-to-positive and negative-to-negative connections from amplier
or receiver to the loudspeaker. The twenty5i series terminals are colour-coded to
aid in their identication: positive terminals are red, negative terminals are black.
–
50+ hours to run-in
RUNNING IN OR BREAKING IN
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50
HOURS
When loudspeakers are new they will take time to reach their full potential.
It is often debated whether any solid-state equipment, such as CD players
or transistor-based power ampliers change with use, but the characteristics
of mechanical devices such as loudspeakers do alter and improve their
performance signicantly after a short ‘running in’ period.
The science is simple; as the soft material surrounding the dome or woofer
cone is exed it will eventually reach a point where it has optimum compliancy
allowing the drive unit to move more freely. This translates to greater accuracy
and speed of attack in the bass region and the mid and high frequency
produces a far more vivid audio picture. This short ‘running in’ period takes
approximately 50 hours of normal use.
POSITIONING
Positioning
With their unique
low distortion and smooth bass roll-off, PMC loudspeakers are more forgiving of
difcult room conditions and placement constraints than conventional designs
so you will be able to achieve a superb sound throughout the room with little
effort. We do encourage you to spend some time experimenting in your own
room in order to achieve the very best results. Remembering that small changes
in location can often inuence system performance.
Room shape, size, construction and interior decoration vary immensely and
therefore inuence sound in different ways. The following guidelines are
suggestions for the starting point to locate your new speakers. Fine-tuning of their
positioning can start from here.
Advanced Transmission Line design, wide dispersion, ultra
ATLTM
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POSITIONING
• Place the speaker so the front face is slightly forward of any large object
that protrudes into the room – eg. a replace, bookcase or television.
TIP – See stereo set up diagram
• Ensure that stereo pairs of loudspeakers are equidistant from the listening
position.
• It is best to position the front left/right pair (and centre channel loudspeaker
if you have a surround system) at the same height, usually at ear-level when
seated at the listening position.
TIP – If any of the speakers are mounted above or below ear level, then angle
the speaker towards the listening position.
• The distance between your left/right speakers and the listening position should
ideally be equal. As a general rule, the width of the audio picture will be narrow
if the speakers are too close together. If they are too far apart the picture will
be wide but there will be less central denition.
TIP – Use a well recorded vocal track to judge the ideal spot.
• To enhance the audio picture/soundstage and sound balance, the speakers
can be angled/toed-in. With the speakers facing straight ahead play a well
recorded vocal track. Gradually toe-in both speakers by small increments (max
5° at a time) (see stereo set-up diagram) until the voice is vivid and centrally
placed. You can ensure this is best position by going ‘one step too far’ then
returning. Then, use a track with extended high frequencies such as cymbals,
check that they sound clear but not overpowering. If they sound too loud or
harsh subtly toe the speakers out by very small increments until you achieve the
ideal balance; then repeat both listening tests to conrm.
TIP – A simple, well-recorded band with vivid vocals will help to nd the best
position.
FINE TUNING FOR PERFECT BASS
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Bass / LF (Low Frequency adjustment)
Solid boundaries (i.e. walls, ceilings and oors) reect sound and help to contain
it within a room. They make a speaker sound louder the closer they are to them,
especially in the low frequency (bass) region.
This diagram shows the areas, that if a speaker is positioned, will either increase
or decrease bass – The darker the shading the more bass will be heard.
Placing the speakers in the corners will generate the most bass, and in the centre
of the room, the least bass.
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STEREO SET UP
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SURROUND SOUND SPECIFIC SET UP
5.1 Systems
The twenty5i series has been designed for perfect multi channel music or movie
playback and the following diagrams display the ideal layout for the speakers.
TIP – No doubt the constraints of room size and shape will vary the distances from
the listener to the speakers. Therefore use of the time alignment function of
your surround processor will be important.
TIP – The guidance given in the ‘Stereo set up’ and ‘Fine tuning for perfect
bass’ also apply to the set up of a surround system.
7.1 Systems
In a system capable of full 7.1 Dolby
Blu-ray™ or HD DVD™ playback there will be two sets of surround speakers.
The rst pair should be positioned at 100º and the second set at 150º. (The centre is
considered 0º while directly to the rear of the room is 180º). See Ideal 7.1 surround
set up diagram.
®
Digital Surround EX™, DTS® ES™,
Other Immersive Surround Formats
DTS:X™, Dolby Atmos™, Auro 3D
®
– we have models to suit every format.
With our vast array of product options it is easy to create a bespoke state-
of-the-art home cinema to take full advantage of the latest surround
sound formats, regardless of the number of channels or placement of the
speakers. In addition to the choices from the twenty5i series we produce in-
wall and on-wall ci series models and both active and passive subwoofers.
See www.pmc-speakers.com for more information.
Dolby® Digital Surround EX™ and Dolby Atmos are registered trademarks of Dolby® Laboratories
DTS® ES™ and DTX:X™ are registered trademarks of DTS®, Inc
Auro 3D® us a registered trademark of Aurio Technologies
Blu-ray™ is a trademark of the Blu-ray™ Disc Association
HD DVD™ is a trademark of the DVD Format/Logo Licensing Corporation (DVD FLLC)
IDEAL 5.1 SURROUND SET UP
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TIP – Four soft, self-adhesive feet are included with the twenty5.Ci. These can be
attached to the base of the unit to provide vibration-free operation.
IDEAL 7.1 SURROUND SOUND SET UP
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For the Dolby Atmos™ system height channels are required. We produce a range
of products to accommodate this. See www.pmc-speakers.com
SERVICE
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We are condent your twenty5i loudspeakers will afford many years of trouble-
free listening of the highest order. B ut in the unlikely event that one or more requires
repair, our unique manufacturing procedure, wherein the precise value of each
component together with the response of the system as a whole is recorded,
will ensure that any replaced parts will exactly match the performance of those
originally included within each individual loudspeaker.
For any issues that might arise, or for advice and service requirements, the primary point
of contact should be your knowledgeable and authorised PMC dealer/distributor.
If you do not have a local representative please see www.pmc-speakers.com
and click on ‘where to buy’.
Alternatively you can view our FAQ’s (Frequently Asked Questions) and servicing
section on our website. (Click on the contacts section and select FAQ).
Important Note: Please do not return any products to PMC directly