PMC twenty5i Series User manual

i
No.
Hand built by
User guide

Warranty
Please take a few moments to complete the warranty card at the
back of this booklet or register at www.pmc-speakers.com (click on ‘register
a product’). This records the purchase of your loudspeakers and provides you,
the customer an opportunity to make suggestions and provide feedback
directly to PMC. To gain your 20 warranty your product must be registered with
us within 10 days of purchase.
Product Support
For product support, accessories or servicing advice, please contact
a PMC authorised retailer – See www.pmc-speakers.com.
IMPORTANT
THE PROFESSIONAL MONITOR COMPANY LIMITED
HOLME COURT, BIGGLESWADE, SG18 9ST, UK
T [phone]
[email protected]
www.pmc-speakers.com
© 2020 PMC. All rights reserved.
Ref No: 1086
PMC Stock Code: 17092
Register now for your
UNRIVALLED
twenty year warranty
YEARS
20

twenty5.21iin Diamond black

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.
WHAT DRIVES US
Peter Thomas, Owner &
Oliver Thomas, Chief Technical Ofcer

CONGRATULATIONS
– YOU HAVE JOINED THE ELITE
UNIVERSAL MUSIC GROUP
Thomas Newman
Royal College of Music
Afrojack
Warner Music
Kraftwerk
Pinewood Studios
Capit Studios
EMI
Stevie Wonder
BBC
Tony Bennett
Coldplay
elbow
ESPN
SONY
Apple
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.

General usage guidelines
PMC’s ATLTM
(Advanced Transmission Line)
LaminairTM
Our meticulous attention to detail
Unpacking
Installing the resonance-absorbing plinth bars
Dedicated twenty5iseries stands
Connections - plugging them in
Running in or breaking in
Positioning
Fine tuning for perfect bass
Stereo set up
Surround sound specic set up
Ideal 5.1 surround sound set up
Ideal 7.1 surround sound set up
Service
Specications
Warranty on-line
Warranty certicate – Part 1 – Your copy
Warranty certicate – Part 2 – Our copy
Help us improve – Your comments
Inspection certicate
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CONTENTS
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Read these instructions and keep them in a safe place for future reference.
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Heed all electrical safety warnings, including any on the loudspeakers themselves.
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Do not use the loudspeakers near water.
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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.
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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.
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Do not install near any heat sources such as radiators, ovens or other equipment
that produce excessive heat.
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Unplug this product from both source and power during electrical storms, or when
unused for extended periods of time.
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Packing material can pose danger to the young and vulnerable. Ensure these
items are kept or disposed of safely.
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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.
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Do not attempt to service the equipment. There are no user serviceable parts
inside. Please refer all servicing to PMC authorised personnel.
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Servicing is required when the apparatus is damaged, exposed to moisture,
or exhibits a distinct or sudden change of operation or audio performance.
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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.
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twenty5iloudspeakers 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.
GENERAL USAGE GUIDELINES
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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 efcient 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.
ATLTM improves more than just the bass response:
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 benet. The ATLTM
bass extension does not change with volume
level – so even when listening quietly the bass
sounds balanced and well dened.
This cross-sectional view of the twenty5.24i
loudspeaker shows the ATL TM cabinet
arrangement and the unique LaminairTM
vents

TM
‘Nothing else comes close to the
clarity, timing, and dynamics.’
Our loudspeaker performance has been taken to
the next level with the addition of the LaminairTM
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 LaminairTM aerodynamic
vent which creates an even smoother, laminar
airow at the exit from the transmission line.
This innovative solution reduces turbulence
and drag at the ATLTM vent, reducing resistance,
increasing efciency, eliminating air noise, and
provides bass with supreme timing and the
ultimate dynamic range.
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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.
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OUR METICULOUS ATTENTION TO DETAIL
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.
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TAKE CARE WHEN UNPACKING – THERE ARE DELICATE
TERMINALS ON THE REAR OF THE CABINET

Re-packing
When re-packing all twenty5iseries
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
PLINTH BARS
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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 specic compliance.
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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 twenty5iseries 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 Dimensions
H599mm +25mm spikes
W229mm
D364mm
Stand Features
• Unique, damped, 3-layer sandwich construction.
• Mass ll-able – sand or shot.
• Built-in cable management.
• Essential to complete the dynamic twenty5iseries look.

CONNECTIONS
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Caution
To avoid potential damage, please ensure that your power amplier(s) or
receiver is turned off before connecting or disconnecting your loudspeakers.
Cable & connectors
When selecting cables for use with your twenty5iseries loudspeakers, ensure
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.
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 amplier
or receiver to the loudspeaker. The twenty5iseries terminals are colour-coded to
aid in their identication: positive terminals are red, negative terminals are black.
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Plugging them in