PMC twenty-21 User manual
series user guide
No.
Hand built by
Date
Warranty Certicate
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.
Product Support
For product support, accessories or servicing advice, please contact
a PMC authorised dealer - See www.pmc-speakers.com.
IMPORTANT - Complete your warranty certicate
THE PROFESSIONAL MONITOR COMPANY LIMITED
43-45 CRAWLEY GREEN ROAD LUTON LU2 OAA UK
T 0870 4441044 F 0870 4441045
© 2014 PMC. All rights reserved.
Version v4 - #100
A message from Peter Thomas –
Peter Thomas
Owner & Chief Designer
“Our sole aim while designing loudspeakers is to recreate the true essence of an artist’s
intention, combining the ultimate level of sonic resolution with solid engineering principles.
We believe that the same loudspeaker can be used throughout the entire audio chain,
from composer to studio or lm stage, post-production or mastering and then, nally,
the consumer. Our unswerving passion for getting it right has made this goal possible.
Thank you for choosing PMC products. It is now time for you to read the user guide,
install your new twenty series speakers, and realise just how much you’ve been missing.
Over two decades PMC has earned an
unrivalled reputation for creating the
world’s nest professional loudspeakers.
Simply put, our loudspeakers provide a
reference for the world’s highest prole
productions and events. They are found
at every stage of the creative process,
from conception to recording and
broadcast and, of course, in the home.
Our client list reads like a who’s who of the
sonically aware, with Prince,
Stevie Wonder, Robbie Williams, Coldplay,
Brian May, Universal, Sony, Dreamworks,
Deutsche Grammophon and the BBC
among the makers of movies and music.
Our loudspeakers were used in the
production of Titanic, Man of Steel, Skyfall,
WALL-E and during broadcasts of both the
Beijing and the London Olympics.
elbow
Stevie Wonder
elton john
BBC
Tony Bennett
Prince
Coldplay
UNIVERSAL MUSIC GROUP
Basement Jaxx
Robbie Williams
Royal College of Music
Brian May
Warner Music
Kraftwerk
Underworld
Emil Berliner/Deutsche Grammophon
Google
Siemens
Sony
JVC Studios
PMC: the authority for quality sound.
Congratulations - You have joined the elite
General usage guidelines
PMC’s TM
Advanced Transmission Line
- Basically speaking
TM
Advanced Transmission Line
- Technically speaking
Our meticulous attention to detail
Unpacking
Resonance absorbing plinth installation guide
Compact loudspeaker set up
Connections
Connecting to an amplier twenty.21, 23, 24 & C
Connecting to an amplier twenty.26
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
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
user guide
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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We have provided a high quality Microber cloth for cleaning. This is ideal as 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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Floor spikes are sharp and should be treated 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 LTD 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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twenty loudspeakers contain very powerful magnets and therefore may have
a detrimental effect if left in close proximity to magnetically sensitive items such as;
CRT (tube style) televisions or monitors and media such as oppy discs, cassettes
and videotapes.
General usage guidelines
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Techn
Basically speaking
TM
Advanced Transmission Line
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The world’s leading professionals rely on the
accuracy of PMC’s designs everyday to
create much of the music and sound you
hear. You can rest assured that what you hear
from a PMC speaker is identical to the version
approved by the artist themselves.
What they offer above a standard HiFi speaker
Detail - They are extremely detailed and
sound natural - As if the musicians are with you
in the room
Room lling - The sound they produce covers
a massive area, so wherever you sit you still
hear everything
Full, rich sound at any volume - You can listen
at low level and still hear bass - Ideal for low
level or late night listening
Reliability - all the components are tried and
tested in the professional world
Ease of drive - They are efcient and therefore
can be driven by the vast majority of good
quality ampliers
Ideal for surround - They all have an
identical tonal balance and can be mixed
and matched to create the ultimate
surround sound system
Easy to position - They sound superb in a
vast array of rooms, large and small
Feel good - They are made in Britain by
hand, by nice people who care, and love
audio
Boast - You have joined the long list of world
famous music makers and recording studios
using PMC’s TM
Advanced Transmission Line
technology -
See www.pmc-speakers.com and click
on key clients
twenty 24 cross section
showing TM
Advanced Transmission Line
•
twenty 22 cross section
showing TM
Advanced Transmission Line
•
ology
turn signicantly reduces distortion. A spin-off
from the lack of distortion is that the upper
bass and midrange detail is not masked by
harmonic distortion residing in the very low
frequencies. The result is PMC’s characteristic
transparent midrange and fast, attacking
bass notes, all reproduced with outstanding
clarity.
A further advantage of the transmission
line approach is a cabinet that produces a
higher volume and greater bass extension
than a ported or sealed design of a similar
size, even if identical drivers were used.
Moreover, as the loading on the main driver
is maintained at all volumes, the frequency
response also remains consistent regardless
of listening level.
Casual late night listening or analytical studio
sessions can be conducted without the need
for high volumes to achieve maximum bass
response. A characteristic that is especially
suited to both the home enthusiast and
recording professional alike.
‘No other technology provides such a huge, rich room lling sound’
Technically speaking
PMC’s TM
Advanced Transmission Line
(Advanced Transmission Line)
enclosures have taken loudspeaker design
to the highest level.
A PMC transmission line design utilises
sophisticated cabinet construction,
proprietary drive units and patented
absorption materials and techniques.
The benets are enormous compared to the
relatively simple sealed and ported models
currently available elsewhere.
The bass driver is placed at one end of a
long tunnel (the transmission line), which is
heavily damped with absorbent acoustic
material. This material is specied to absorb
the upper bass and higher frequencies that
radiate from the rear of the bass driver.
The lowest frequencies, which remain in
phase, then emerge from the large vent at
the end of the line, which essentially acts as
an additional driver. One advantage to this
approach is that the air pressure loading the
main driver is maintained, thus controlling the
driver over a wide frequency range, which in
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All PMC loudspeakers are 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
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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.
!
Resonance absorbing plinth installation
guide for oorstanding models
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Resonance damping plinths and spikes enhance the performance and
stability of the oorstanding models in the range. The plinths attach to the
base of each speaker using M8 bolts. The twenty series spikes are reversible,
with spike or ball tips for use on either carpeted or more sensitive hard
ooring.
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Carefully invert the loudspeaker so that its base is uppermost. Take
care not to damage the top of the loudspeaker when it is upside-
down, the use of a soft cloth or square of carpet is suggested.
Position the plinth on the bottom of the loudspeaker so that its large
curved edge is to the rear (same face as 4mm terminals/sockets).
Ensure that the corresponding inserts in the base of the cabinet are
aligned with the rebated holes in the plinth.
Locate the large M8 bolts and tighten them gently using the allen key
supplied until the heads of the bolts are ush with the plinth’s surface.
Once the bolts are ush carefully tighten each bolt by half a turn
N.B. Do not over tighten. Over tightening will reduce the effect of the
resonance absorbing material
Fully thread each spike with one of the supplied lock nuts. The spikes
can then be attached to the plinth; they should point upwards whilst
the cabinet is inverted.
Caution: the spikes are sharp and should be treated with great care
and may damage hard ooring if in direct contact
N.B. You have the option of using the ball tips for use on more sensitive
ooring
Re-invert the loudspeaker so that the spikes and plinth are at the
bottom.
Once in position, level the loudspeaker by adjusting each spike in turn.
The nal step is to tighten each spike’s lock nut with the spanner
provided; this will ensure that the spike and loudspeaker are as rigid as
possible.
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Compact loudspeaker set up
The compact twenty series models are designed to offer
exceptional clarity while taking up minimal space, either on stands
or within audio/video furniture.
They will realise their optimum performance when used
in conjunction with their dedicated high-mass stand that
positions them at the ideal height with stability.
• Unique, damped, 3 layer sandwich construction
• Mass ll-able – sand or shot
• Cable management
• Essential to complete the dynamic twenty look
H599mm +25mm spikes W229mm D364mm
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 twenty series 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 twenty series 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.
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 twenty series terminals are colour-coded to
aid in their identication, positive terminals are red, negative terminals are black.
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Standard / Single wiring connection
This is the most common, using a single cable with two conductors.
Connect using any of the two pairs of RED+/BLACK- terminals. Ensuring the
twenty series terminals and gold linking bars are secure and the binding posts are
nger tight.
Advanced connection / Bi-wiring & Bi-amping
twenty series models with four binding posts can be bi-wired or bi-amped.
By loosening all four rear binding posts, the gold linking bars can be removed
thus enabling separate signals to be fed to the low (Woofer) and high frequency
(Tweeter) drivers. Ensure the binding posts are re-tightened after the bridging bars
are removed. Both bi-wiring and bi-amping require the use of two lengths of cable
per speaker. Bi-amping requires two separate ampliers; one for each driver.
Please consult your dealer regarding the benets and the correct procedure.
Terminal identication
Top pair of terminals - HF / High Frequency / Tweeter
Bottom pair of terminals – LF / Bass Frequency / Woofer
Back panel
Connecting to an amplier
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HF
LF
HF
LF
LEFT
LEFT
Standard/single wiring Bi-wiring Bi-amp connection
HF
LF
Standard / Single wiring connection
Connect using any of the three pairs of RED+/BLACK- terminals. Ensure the linking
bars are secure and the binding posts are nger tight.
Advanced connection / Bi-wiring & Bi-amping
The twenty.26 can also be bi-wired, bi-amped, tri-wired or tri-amplied. By loosening
all six rear binding posts, the linking bars can be removed so separate signals can
be fed to the LF (Woofer), MF (50mm Dome) and HF (Tweeter) drivers. Ensure the
binding posts are re-tightened after the linking bars are removed.
Both bi-wiring and bi-amping use two lengths of cable per speaker, tri-
wiring and tri-amping use three lengths per speaker. Bi-amping also
uses two separate ampliers; tri-amping uses three, one for each driver.
Please consult your dealer regarding the benets and the correct procedure.
Terminal identication
Top pair of terminals - HF / High Frequency / Tweeter
Middle pair of terminals - MF / Mid Frequency / 50mm Dome
Bottom pair of terminals - LF / Bass Frequency / Woofer
Back panel
Connecting to an amplier
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Standard/single wiring Bi-wiring Tri-wiring
Bi-amp wiring Tri-amp wiring
HF
LF
MF
HF
LF
+
-
MF
HF
LF
MF
HF
LF
MF +
+
-
-
+
-
HF
LF
MF
+
+
-
-
HF
MF
LF
HF & MF
LF
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.
50+ hours to run-in
Running in or breaking in
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With their unique TM
Advanced Transmission Line
Advanced Transmission Line design, wide dispersion, ultra
low distortion and smooth bass roll-off, PMC loudspeakers are more forgiving of
difcult room conditions and placement constraints than conventional designs
- 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.
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Positioning
Positioning
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• Place the speaker so the front face is slightly forward of any large object
that protrudes into the room - this could be a replace, bookcase
or television for example.
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.
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 create an equilateral triangle. 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
Use a well recorded vocal track to judge the ideal spot.
• To further enhance the audio picture or soundstage the speakers can
be angled/toed-in’. Start with the speakers angled so they will cross
approximately 50cm (2ft) behind the listening position. (See stereo set-up
diagram) Varying this angle will also subtly affect the vividness of the audio
picture, so again experiment.
A simple well recorded band with vivid vocals will help to achieve the best
position
Positioning
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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.
Fine tuning for perfect bass
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This manual suits for next models
5
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