amplifiers, cables and wiring-up introduction stands important

amplifiers, cables and wiring-up introduction stands important
V5 Nov 2010
Here at Harbeth we are dedicated to reproducing the
musicality and warmth of natural sound. With careful use,
Harbeth speakers will give you very many satisfying years of
listening pleasure, and time will prove your new loudspeakers to be the ultimate audio investment. I warmly welcome
you as a customer and encourage you to join the Harbeth
User Group and share your experiences with other Harbeth
owners who like you, are serious about high fidelity natural
Alan A. Shaw, Managing Director and Designer, Harbeth UK.
Before you attempt to lift the speakers from their carton
please take note of the staples running top to bottom
along one long edge of the carton. Open the carton’s top
flaps, remove the packing cap and take care to avoid
contact between the staples and speaker cabinet.
Retain the packing in a dry place.
Harbeth loudspeakers are precision instruments. Their
cabinets are crafted from a complex interplay of natural and
man made materials, every small detail of which exists for a
specific acoustic purpose. The incredible resolving ability of
the fresh, clean Harbeth sound is a combination of leadingedge science and traditional values. After exercising your
new Harbeths for just a few hours they’ll be fully ready for a
lifetime of enjoyment.
This manual makes a few suggestions for how to extract the
best possible performance from your audio system. Your
own experience must guide you, and what really matters is
what sounds best to you in your room, with your music, your
taste and your equipment. Don’t hesitate to turn to the User
Group for help and advice.
Musical appreciation is an ongoing relationship between performers, recording engineers, equipment designers, you and
your audio dealer. He’s there to help you to get the best from
your hi-fi and has the time and the skills to experiment.
Keep an open mind as to new musical avenues, equipment
and accessories. Above all, trust your own ears.
Harbeth speakers are at their best when used in ‘free-field’
conditions. This implies that the speakers are raised off the
floor and as far as possible away from adjacent surfaces on
stands made from a rigid and non-resonant material, including wood, sand-filled steel or polymers. If you have children
or animals at home be sure to put safety first as our
speakers are heavy. The top-plate of the stands must be
adequately large and the stands themselves solid and stable
to prevent the speakers from toppling over and causing
injury or damage.
The cabinet may be attached to the stand’s top-plate with a
small pea-sized ball of “BluTak”, cork or rubber cushioning
dots, cones or spikes. Note: only use the absolute minimum
amount of BluTak as it will permanently bond to the veneer
and cannot be removed. Speaker stands are usually fitted
with sharp spiked feet that further improve stability.
Ideally the stands should place the tweeter approximately
level with your ear when seated in your usual listening chair
- the so-called ‘reference axis’ where the frequency response
is optimised. Tall stands lift the speaker further away from
the floor which adjusts the bass quality but there is always a
compromise between the cosmetics of tall stands, ideal
listening height and stability.
Although the reference listening axis is directly facing the
front baffle, some users prefer both speakers toed-in towards
the listening seat by 5-15°. Adjusting the toe-in alters the
balance especially between the mid and high frequencies in
your room according to your preference.
Harbeths are designed to present an ‘easy’ electrical load to
the amplifier and will work well with valve (tube), transistor,
MOSFET and digital solid-state amplifiers. Playing loud in a
large acoustically dry, well furnished room will demand a
powerful amplifier. Conversely in a smaller setting listening
closer to the speakers, much less power is needed. As an
approximation, for normal domestic listening an amplifier of
about 45W into 8 ohm per channel rating is a good starting
point and 100W into 8 ohm per channel would provide a
reserve of power for the louder musical passages if used
with care. Be aware that small amplifiers with limited power
output may ‘clip’ when driven hard and as clipping can
damage loudspeaker drive units it is not covered by our
Warranty. The amplifier’s performance can change over
time, and it should ideally be tested and recalibrated as its
circuitry ages.
Safety first!
The amplifier’s volume control is just like the zoom lens and
lets you bring the performers closer to you. Every sound
recording has an optimum loudness; not too close and not
too far away so that the scale, perspective, detail and tonal
colours are in their correct proportion. Listening at home at a
responsible loudness of around 85dB is considered a longterm sensible exposure by health experts and acceptable by
many neighbours: Harbeth speakers are uniquely optimised
to sound natural and full at that safe listening level.
Turn off your amplifier BEFORE making any changes to
the wiring of your audio system or speakers.
Setup A - Single-wiring (preferred standard method)
Where four terminals are supplied the bi-wire links must be
fitted to bridge the speaker’s red-to-red and black-to-black
terminals or where only two terminals are fitted, connect to
your amplifier like this ....
There are many differing views about interconnect and
speaker cables. Your dealer can provide invaluable advice
so we’ll leave that for you to explore and concentrate here
on the basics of hooking-up to your amplifier. Conventional
QED-like 79-strand cable (or similar) is all you need to get
you going. Thin, high resistance cables or exotic cables with
a strange construction may exhibit high capacitance and/or
inductance characteristics and definitely should be avoided
as they will produce unpredictable results and could damage
your amplifier. Where practicable use the same, shortestpossible cable lengths between amplifier and speakers. Your
dealer will be pleased to make-up and supply cables at just
the right length, terminated with the most suitable connectors
for your equipment and can give you advice on cable
The rear terminal panel of your Harbeth speakers carries red
coded and black coded connectors. Some models feature
four connectors (permitting a bi-wiring connection arrangement) so the upper pair are connected internally to the
tweeter via its crossover network and the lower pair to the
woofer through its circuitry. Other models have one single
red/black pair of input binding posts. The standard singlewiring connection method is the simplest, safest and
quickest method of connecting to your amplifier as shown in
Setup A.
Reportedly, the so-called 4mm banana plugs commonly
used for connecting speakers to amplifiers can be confused
with two-pin mains plugs. Your dealer will be able to advise
you whether or not 4mm speaker plugs are acceptable in
your country. As an alternative you can use spade
connectors or with care, bare wire ends if the surplus wire is
trimmed off.
It is extremely important to connect your Harbeths with the
proper phase between the left and right channels and in
bi-wiring/bi-amping configurations between the woofer and
tweeter connections in each speaker. Wiring-up your speakers is much simpler if you select a clearly colour-coded cable
where the ‘hot’ (+) or ‘cold’ (-) conductors are unmistakably
identified by colour, rib or stripe running continuously along
the sheath. Some cables only have a faint coloured identifier
printed infrequently so please take care! Incorrect connections will make natural sound reproduction impossible and
could damage your amplifier. Always recheck the wiring
before powering up the system after making any changes
and look out for fine strands of wire that can stray between
terminals and cause a short circuit.
Never allow a (+) conductor to touch (short) against a (-)
conductor even for a second as some amplifiers cannot
tolerate output short-circuits no matter how brief.
Setup B - Bi-wiring for speakers with four rear terminals
First, remove the bi-wire links and connect two pairs of
cables to each speaker. From the amplifier’s red (+) terminal
run two conductors to both of the speaker’s red terminals.
From the amplifier’s black (-) terminal connect to both of the
speaker’s black terminals. You must identify with certainty
the polarity of all the conductors at both ends of the cable to
avoid confusion. Incorrect wiring will result in a short-circuit
with potentially serious consequences to the amplifier.
Bi-amping (not shown) is the most complex arrangement. It
is essential to remove all four bi-wire links before setting-up
for bi-amping which mandates two absolutely identical and
calibrated stereo amplifiers wired so that one complete
stereo amplifier drives each loudspeaker e.g. the amplifier
left channel drives the woofer and the amplifier right channel
drives the tweeter. The wiring is complex and the performance of the whole system entirely depends on amplifier characteristics and set-up. Even the smallest variations in gain
between the channels of a normal hi-fi amplifier will be
enough to alter the relative balance between the bass/mid
and high frequencies from what we intended.
Bi-amping your speakers is specifically excluded from
Harbeth’s Warranty as it requires test equipment to set-up
properly and strict attention to wiring. We regret that we
cannot provide detailed advice on bi-amping.
When you have completed your wiring, be sure to route the
speaker cables carefully to prevent anyone tripping over
A sonic compromise has to be reached between positioning
the speakers unobtrusively near walls or positioned further
out in the listening area. When a loudspeaker is close to a
boundary wall (floor, ceiling or corner) the speaker becomes
cies and flexible plasterboard walls and wooden floors over
cavities such as a basement or garage may resonate and
cause boom. However, curtains, thick carpets, rugs and
bookcases positioned at strategic points to minimise reflections in the room (see picture) can make a dramatic improvement in fidelity; pleated curtains on tracks across windows or
side walls are an excellent way of temporarily adjusting room
acoustics. Optimising your speakers in your room needs
experimentation but the general rule is the more absorptive
the room, the less the room influences the sound.
Fortunately the ear is forgiving of all but the most severe
room acoustic problems.
Tone controls and modern digital signal processing roomcorrection systems can, when used carefully, offer a solution
especially in the lower frequencies. They may be of little or
no help in the middle and upper frequencies where conventional soft-fabric treatments are the best solution to damping
a ‘live’ room.
acoustically coupled to the surface, just as if it is actually
attached to it. The speaker then no longer operates in ‘free
space’ with a predictably flat frequency response but with
an elevated low/mid frequency output that, whilst not
necessarily unpleasant, adds a lushness to the lower
registers. Well stocked bookcases behind or beside speakers can greatly improve the low frequencies as can an asymmetrically placement of the speakers. Below is an example
of a typical set-up.
Prepare yourself to hear unexpected details in even your
most cherished recordings that you previously did not realise
were there, Now a first class recording conjures up a solid
3D holographic performance - a curtain of sound - between
and beyond the speakers. Listen out for the way that the
crystalline inner clarity of the Harbeth RADIAL™ cones really
does transport you back in time and space to the recording
venue itself. Do bear in mind that almost all recent commercial recordings have been sonically processed to enhance
their marketability as may be exposed by the greater resolution of your Harbeth speakers. It is a fact that many of the
most natural recordings and performances were produced
years ago on simple equipment. Please share your choice of
showcase recordings with us on the Harbeth User Group.
To maintain your speakers occasionally wipe over the wood
with a slightly damp cloth rinsed in a specialist detergent
suitable for wood veneer. Do not use waxy polishes. Please
avoid direct sunlight, radiators, draughts, smoke, ozone and
other chemicals on or near the cabinets. The special
Harbeth SuperGrilles™ should be fitted during listening.
They can be cleaned with a soft, dry clean paint brush. Do
not press or touch the drive units under or through the grille;
if necessary the bass unit can be cleaned with a photographers air-brush not a cloth. Do not clean the tweeter.
HALUG V5 Nov 2010 Final
Some listeners say that the most natural sound stage is
achieved when the speakers are slightly closer to each other
than they are away from the listener (above) but please
experiment for yourself.
The ear does not like standing waves or echoes which you
can identify by moving around your room and loudly clapping
your hands. Parallel surfaces such as opposite walls, floor
and ceiling encourage and sustain these problem frequen-
With our attention to detail during production, Harbeth
speakers will give a long trouble free service life if operated at
a normal responsible volume level. The ex-factory Warranty
can be extended (subject to conditions) by Registering your
speakers on the Harbeth website. Finally, thank you: we
wish you many years of great listening.
Harbeth Audio Ltd.
3 Enterprise Park,
Lindfield, Haywards Heath,
West Sussex, RH16 2LH, England.
Tel: 01444 484371
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