Wilson Benesch Bishop User manual

WILSON BENESCH
Loudspeakers
The Bishop
All invention is simply an extension of man.
In the case of so many Wilson Benesch products not only are
the organic forms a clear manifestation of this philosophy ut of
course, eing car on ased, the links etween the materials
employed in the construction of oth the invention and Man are
clear. Materials technology is one aspect of the innovation that
has een rought to the domestic audio market y Wilson
Benesch. In a rief time the company has esta lished itself
throughout the world and can e proud of its achievements.
We would like to thank you for sharing our view on what
represents good design y choosing our product a ove all
others.
We are confident that you will enjoy them as much as we do.

WILSON BENESCH
Loudspeaker Specification
The Bishop
Type:
Floor standing. Infinite affle on oth low frequency and discrete mid range system.
Range:
Full frequency: 25 Hz to 20 kHz
± 2.5 dB 40 Hz to 20 kHz
Impedance loading:
6 Ohms nominal, 4 Ohm minimum 20 Hz to 20 kHz
Sensitivity:
87 dB @1m, 2.83V input
Crossover:
Minimum phase, short signal path. Air core inductors, selected polypropylene
capacitors.
Low frequency driver array:
• Iso aric
Tactic

System:
Eight Wilson Benesch
Tactic

Drive units are used in a clamshell Iso aric
configuration. The
Tactic

drive unit has een developed in order to fulfill a
multi role function to achieve maximum integration. It represents the State of The
Art in driver technology.
Benefits.
NdFeB rare earth axially magnetised super low profile gas flowed motor system.
High linearity 170 mm driver; 38 mm high temperature voice coil. The world’s first
Isotactic polypropylene with convex / concave diaphragm.
Aluminium alloy gas flowed low reflection asket. Machined from a solid illet.
• Mid range Tactic

driver:
Wilson Benesch
Tactic

Drive unit. The Tactic

drive was developed as a multi
role unit. Integration is axiomatic. The mid range
Tactic

driver features the same
high quality, innovative drive motor used in the Iso aric
Tactic

.
• Tre le driver:
Wide andwidth, cham er loaded 25 mm woven silk dome, Super Revelator.
Internal wiring:
Teflon sleeve low loss silver plated high purity copper wire used throughout the
speaker.
ower handling:
Maximum level: 112 dB at 1 metre
200 W peak programme
Input:
Tri-wire gold plated Wilson Benesch 4 mm socket/ inding posts. Spanner provided
for gold plated nuts.
Size:
Height:1610 mm
Width:230 mm
Depth:560 mm
Weight: 90 kg
Internal volume: 75 litres
All Wilson Benesch products are su ject to continuous improvement. Because superior
technology rings improvements in performance we reserve the right to make changes to the
a ove specification accordingly.

WILSON BENESCH BISHO
SETTING U INSTRUCTIONS.
Important oints before Setting up
Carefully remove all packaging to gain access to the enclosures. During installation it is
helpful to have some one to assist as the speakers are quite heavy. Remove the tools and
spikes which are packaged separately. Please take a little time to read the rest of this ooklet
efore you egin setting up the system. You are advised to retain all packaging as it is
essential for shipping the system safely.
Patient and careful setting is essential to o taining the maximum performance from this
system.
Note well the PRECAUTIONS stated elow.
The NdFeb Magnets.
These are powerful motors do not ring any metallic o jects or sensitive electronic electro
magnetic or mechanical systems into close proximity of these devices. The company cannot
accept responsi ility for any damage to any such systems as a result of accidental damage.
Location
Please refer to the section at the ack of this manual in order to determine position.
Spikes
The Spikes that have een specifically designed for the Bishop Loudspeakers should e
treated with caution. Turned from stainless steel which is very hard they are very sharp and
can easily inflict a severe wound to the unsuspecting and careless. When setting up the
speakers it is a good idea to leave the spikes off the speakers until the correct position for
their operation has een found.
PRECAUTION : WHEN POSITIONING THE SPEAKER IN
THE ROOM ENSURE THE SURFACE HAS NO SHARP
PROTRUSIONS WHICH WILL SCRATCH THE HIGH
QUALITY SURFACES OF THE ENCLOSURE.
When the position has een identified through listening tests, tape can e used to mark the
location prior to moving to one side to install the spikes. The vertical attitude of the speaker
can e varied. The position of the tweeter has een designed to function est for listeners
seated in conventional relaxed seating positions. If required for other situations such as
listeners on higher seating or standing the speakers can e tilted ack so as to fire the tweeter
upwards.
The spikes are manufactured y Wilson Benesch and have een engineered to uncommonly
high standards. They must e nipped up with the spanner provided in order for them to
function properly. Do not under any circumstances apply a great deal of force as this may
relieve the front spike oss from the foot. Large torsional loads are simply not necessary, just
enough force to gently lock the spike in place.

Terminals
PRECAUTION : DO NOT OVER STRAIN THE TERMINAL WHEN CLAMPING
CABLES.
(Wilson Benesch recommend 8mm Ring Connector ca le terminations)
The Terminals have a crucial role to play which must e executed relia ly over long periods
of time. Wilson Benesch terminals are a piece of industrial design in themselves. Their
elegance is orn of simplicity and they achieve their purpose without compromise. They
were designed y Wilson Benesch in order to achieve the level of performance required y
the advanced design, of which they form an important part. They provide the shortest
possi le route for the signal and in this aspect they out perform all other terminals currently
availa le. They are turned from a single ar of high purity rass and exploit the common nut
to ensure a relia le, vi ration free termination of the ca le to a massive surface area. Exploit
good quality 8mm diameter ring connectors and you will achieve the est possi le link. You
can e sure that this inexpensive nut will e just as tight today as it will tomorrow or the next
year and once locked you can forget a out it, out of sight, peace of mind ca le terminations.
A spanner is provided to nip up the gold plated rass nuts, ut e careful - rass is a soft
material.
The terminals also allow the use of anana plugs, ut push in connectors always represent a
compromise over the superior screw thread and ring terminal connection descri ed a ove.
Running In
Like anything of good quality a period of running in tends to see improvements in
performance. The speaker ca inet requires time to settle in to its surroundings. Climatic
variations and humidity will take time to adjust to and until such adjustments have een
made the speaker will not perform at its est. The drivers require time to ed in physically
and relax materially. The car on panels actually improve in structural integrity as they age.
The quality of the sound that you hear when you first use your Bishops will improve quite
significantly over time though the change will not e instantly percepti le.
Surface Finish
Car on fi re is a unique material with unusual physical and visual characteristics. We like to
remain truthful a out the fi rous nature of the material as opposed to concealing or
o scuring it. It should e appreciated that whilst we take every effort to produce a solutely
perfect panels the occurrence of slight distortions in the fa ric is inevita le. This
phenomenon is virtually impossi le to control and is a natural characteristic of the material.
The natural wood components are manufactured using real-wood veneers. They will darken
over time and, depending on the climatic and heating conditions will stress relieve. This is a
natural phenomenon that may cause slight changes in the dimensions of the wood. These are
typically impercepti le.
The surface finishes applied to the Bishop Loudspeakers do not require anything other than
the occasional dusting. Treat the driver cones with respect and they will last a decade with
relative ease.
Due to the angle of the ca inet top, the appearance of stains as a result of the inconsiderate
placing of a glass is of course impossi le.
With a little care the speakers will look as good in ten years as they do to-day and will
pro a ly sound even etter!

OTHER ADJUSTMENTS.
Under no circumstance should you make any adjustments to the systems parts. Any
adjustments not descri ed a ove as required y the setting up procedure will nullify all
guarantees.
Should there e any question regarding the performance of this system you should refer to
your dealer immediately for advice and or assistance. If in the unlikely event that the pro lem
cannot e dealt with y your dealer do not under any circumstances return the goods to
Wilson Benesch without prior consultation with Wilson Benesch. Wilson Benesch will not
accept any lia ility for costs incurred y the owner for goods returned without prior
notification through the dealer. Wilson Benesch will not accept responsi ility for any damage
that might occur to the speakers during shipment unless it is y prior notice through the
dealer.
The subject of room acoustics.
Acoustics is a complex su ject and this text should e treated for what it is, a simple ut for
some informative guide. For a more in-depth understanding you would need to refer to a
whole range of texts on the su ject. The most important outcome of this should e the
greater appreciation of the role played y the room on the overall sound of the audio system.
The air contained within the room is the link etween the output of the loudspeaker and
your ear. How air ehaves is dependent upon the attri utes or character of the room. It
follows that a etter understanding of asic acoustics and what facets cause the most
influence in the room will assist in making decisions a out the way in which the room and
su sequently the system can e improved.
Room types fall etween two extremes. A room can e “dead” on the one hand (full of
highly energy a sor ent materials and complex diffusing structures) or very “lively” on the
other (few reflective surfaces and a high proportion of very reflective hard non a sor ent
surfaces). As so often is the case, a alance of materials is commonly prefera le to one
extreme or the other. The correct alance for the end user is the goal.
Room attributes which can be changed easily.
The contents of the room impact upon the overall acoustic character of the room. As you
would expect, hard surfaces like glass and concrete tend to reflect a road and of acoustic
energy. Complimentary materials that are soft and thick in section such as heavy natural fi re
curtains will tend to a sor a road and of frequencies.
Room attributes that require more consideration.
The other important factor is room dimensions shape and su stantial internal structures
within the room.
What are Standing waves?
Soundwaves reflecting etween two parallel walls set up resonance modes when :-
One-half, or a whole multiple of one-half, the wavelength of the sound wave is equal to the
distance etween the walls.
These resonance modes are referred to as “standing waves”. In loudspeakers with parallel
walls these waves will cause distortions. The standing waves in your room will distort the
reproduction of your system sympathetically oosting certain frequencies.

If a certain standing wave frequency is acoustically isolated from its modal neigh ors, its
effect is more likely to e audi le and pro lematic. This can compromise the accuracy of any
loudspeaker.
To analyse your room for standing waves we would recommend that you work upto a out
300 Hz. Beyond this point they ecome less relevant and difficult to perceive.
Any standing wave elow 300 Hz is detecta le and should they com ine sympathetically the
result will e a lumping together and this is very undesira le. Evenly distri uted modes are
the goal.
Characterising the room.
Characterising the ehaviour of the room is the first step towards your understanding of
your listening room’s contri ution to the audio system. Follow the simple procedure elow
to o tain a etter understanding where changes could e made in order realise
improvements.
1. Record data of the room dimensions onto a simple floor plan. The graph paper can assist
you with this.
2. Apply the data (dimensions) to the formula
3. Make a record of the predicted standing wave frequency characteristic for each parallel
wall dimension of the room.
4. Verify your predictions using the Wilson Benesch test CD which has a num er of fixed
frequency tests and swept frequencies. Use these to verify and ack up your predictions.
Note 1 ig differences in perceived and calculated values will indicate an error
Note 2 If the predicted frequency matches with the percepti le increase in output in the
room this has verified your prediction.
Note 3 The listening tests should e taken whilst seated in the main listening position.
Evaluate the data and look for errors.
5. Assess whether changes should e made and what can e changed in order to overcome
any dramatic and clearly in-accurate increase in sound pressure levels.
Middle and High Frequency Room Characteristics.
The middle and high frequencies are effected more y room contents rather than room
shape. The “sound” of a room is descri ed y the surfaces and how they reflect, absorb or
diffuse the acoustic energy. Like all energy, acoustic energy cannot e destroyed, it can only
e converted into something else or reflected. The shape of the surface will determine how it
is reflected and the material will determine whether it is a sor ed. All rooms have a
particular sound, and to appreciate what influences are present in your room you should e
aware of how the o jects in your room will respond to sound.
Sound waves ehave in the same way as light waves or "rays" and so imagine the driver to e
a flood light.
Reflection: acoustic energy is not converted ut reflected in an orderly, predicta le fashion.
Diffusion: acoustic energy is dispersed in a random and or disordered fashion.
Absorption: acoustic energy is converted into kinetic energy or heat. All or a majority of the
sound energy is "soaked up" or disposed of y the o ject surface or room oundary.

Loudspeaker positioning
There is no o jective criteria that can e used to state precisely where loudspeakers should
e positioned. Should any individual or company suggest that there is, they should e
regarded as special people and treated with a great deal of caution. In the glo al scenario our
loudspeakers are driven y unique systems that are selected y the owner ecause of
particular virtues. Every listening room is as individual and unique in character as the owner.
Compound this complex picture with the com ination of different equipment. Consider the
changea ility of rooms, if the room is dressed with heavy curtains simply changing the
curtains position can alter the whole alance of the system. The only rule is that there are no
rules. Like producing good wine it is the goal that is the only guide. The owner is the pivot in
this su tle alancing act.
The goal of high performance audio systems is accurate reproduction. The information e it
in groove or pit form should e transcri ed, amplified and converted ack into sound energy
without the additional views of the audio equipment designer eing com ined with that
translation process.
When one considers this and finally that what one actually hears is a unique experience and
su ject to the realms of su jective evaluation It is for these reasons that when making
recommendations a out positioning loudspeakers it is only possi le for very general advice
to e given.
In order to make the task of positioning the loudspeakers less complex we would like to
make the following suggestions. That most valua le commodity, time, is the most important
ingredient in this process. Be prepared to make small changes over longer periods of time.
Chose four musical passages that you are familiar with that can fulfill the following tests.
They should all e stereo recordings.
Select one with a distinctive and easily heard human voice. Spoken voice is ideal.
Select one passage with a full orchestra like The Pines of Rome.
Select one that is very emotional for you.
Select one that has a strong rhythm as in the case of dance music.
You should appraise the performance of the loudspeakers according to your needs ased
upon the tests a ove.
The ower of Limits.

Air, the medium y which dynamic drivers communicate can e regarded as a liquid, very
difficult to predict and even more difficult to control. When the driver is uilt into a small
enclosure the complexity of this pro lem inevita ly grows and in fact, of all the
components in the audio chain it is the loudspeaker that produces y far the highest
levels of distortion. Although the potential for improvement is large, the physical
pro lems that must e addressed are of similar proportions.
A well known audio critic asserts in his opening paragraph that the drive unit is the major
component of modern loudspeaker design. Whilst we would agree it is important it is as
we have clearly demonstrated, no more important than the enclosure.
The moving coil drive unit is a powerful oscillating motor. It reacts with the enclosure in
its effort to convert electrical energy to sound. Undesira le y products created during
this process must e eliminated as much as possi le. To date all ut very few enclosure
designs have chosen to discount or underestimate the importance of this key concern.
Typically such enclosures can e seen to e composed of flat panels which can e easily
excited. The inevita le predominance of standing waves and high levels of diffraction all
com ine to destroy the accurate recreation of sound. The limitation here is the ca inet
makers ox. The a ility of such designs to perform has always een compromised from
the outset. The larger the ox the more the system could e seen to go eyond its severe
limitations.
In contrast the BBC LS3 5a was successful ecause it recognised these limitations. It
minimised the pro lem of ca inet distortion y accepting the limitations of the
technology. The generation of low frequency energy poses major pro lems so y limiting
the low frequency response it confined its task to the andwidth of its limitations. The
choice of a small, light ut very strong ox was the outcome of this philosophy, a classic
solution. For Wilson Benesch it was the recognition of these limits and a similar respect
for the physical limitations of materials that informed our approach. This emerged from
our work in turnta le design where we had pioneered the use of car on fi re and
Advanced Composite Technology structures. The limits can e pushed ack, ut it
requires research and development and the application of leading edge technology and
assem ly techniques. The A.C.T. One Loudspeaker enclosure was the conclusion of this
philosophy. Its success has clearly demonstrated just how important the enclosure is.
Within its limitations the A.C.T. One enclosure made high quality, low frequency
reproduction achieva le. For other audio engineers as well as audio critics it su sequently
ecame an invalua le development tool. When we attempted to extend these limitations
y demanding a lower frequency response we went eyond those limits. Overcoming this
significant technological challenge has een the principle focus for our research over the
last three years.
The enchmark that the A.C.T. One loudspeaker set in terms of integration and mid range
transparency prescri ed that the low frequency performance should e similar in every
regard. The outcome of this development has major implications for the company which
can now oast a manufacturing facility for advanced moving coil drive units that have
successfully overcome the limitations of the drive units currently used in the A.C.T. One
Loudspeaker.
The Bishop loudspeaker system exploits this new technology to the full.
Conceived, developed and manufactured from raw materials y Wilson Benesch
The Tactic® is an adaptive design. In the mid range system it functions in parallel.
In the low frequency system it takes the form of a composite system the Isobaric
Tactic® The Bishop is a unique product. It incorporates the most advanced
technology ut in a simple way, the hallmark of Wilson Benesch design.
The Bishop: General Design Features.

The Bishop was developed with two discrete isolated enclosures for the low
frequency, mid range and high frequency systems. This immediately reduces
corruption from cross communication. A two ox system also provides other
advantages in terms of manufacturing and installation. Curved pre stressed
Advanced Composite Technology panels are key structural components in oth
ca inets. An organic moulded car on component has een developed to facilitate
low defraction and negligi le resonance from this critical part of the structure. The
form and angle of rake eliminates the potential for ceiling to ox top interactions.
The whole system is mounted on a su stantial foot system which also houses the
adjusta le crossover system whilst providing a high degree of sta ility. All
components are manufactured in house with the exception of the tweeter which is
specified to Wilson Benesch specifications and mounted in a simple ut very
effective damping ring on the alloy MDF composite affle structure. It provides
clearly defined information from 5kHz to 20 kHz via a single inductor capacitor 1
st
order crossover network. Its position has een derived from trials which focused
upon phase coherence. The Mid range units are driven well within their prescri ed
specification and are controlled y a andpass filter. All low frequency information
eing devoted exclusively to the Iso aric Tactic® system. Significantly low
frequency energy is provided y drivers that are almost identical to the mid range
systems. This dictates that integration and phase coherence will e virtually
guaranteed. To further overcome the enormous challenge of low frequency
reproduction these units have een mounted in a clamshell composite configuration
which we call the Isobaric Tactic®. By exploiting the principles of the Iso aric
loading the volume required y the low frequency driver array, ( eight in each
channel ) has een minimised despite this advantage it is still five times greater than
that of the A.C.T. One Loudspeaker low frequency enclosure. This has een
achieved y extending oth height and depth ut not width. This important detail
maintains the slim forward facing profile which is crucial for imaging and
transparency. Moreover, the exterior has een extended without accepting the
unaccepta le compromise of the flat surface. Low frequency production is extended
down to 30Hz without the use of the ported enclosure loading which is
compromised from the outset due to the highly resonant characteristics of the port
output which is of course is always 180 degrees out of phase. This delay is
eliminated in the infinite affle arrangement. The speed of the attack and decay are
the main enefactors as a result of this approach.
The Tactic® Dynamic Driver.
Early in 1996 a 12 month feasi ility study concluded that currently availa le driver
technology would not e capa le of taking the companies am itions forward. The
study indicated further, that significant potential for development existed ut that it
would e a major under taking. The decision was taken for us in many ways, the
moment we realised how innovative the final product would e. At that time our
attentions were focused on the creation of low frequency information and in
particular the a ility of that system to integrate well with the improved mid range
performance. A variety of diaphragm sizes were assessed including race track types.
Orientation was also studied, side firing nota ly eing the most un-popular. Loading
the system with transmission lines was appraised as was the closed ox. Many hours
of research was devoted to the
search for a solution to the pro lem. The reakthrough was made when the Iso aric
method was explored. Using B stock Scan drivers in a hastily assem led MDF ox,
for the first time, it was instantly recognised as the right solution. An o vious
answer in
retrospect for with drivers of similar physical proportions to the mid range system
matching would e axiomatic. For the first time we could hear highly integrated,
high performance reproduction that was un-questiona ly superior to the A.C.T.
One.

We identified a num er technologists that would help us surmount the gaps in our
capa ility to manufacture our own drivers entirely at Falcon House. In colla oration
with these engineers the company has moved forward rapidly. CAD / CAM systems
have played a ig part in accelerating the work. Prototypes have een made in
num ers and fine tuning has een simplified as a direct result of this manufacturing
capa ility.
The Tactic® Dynamic Driver, outline of component parts.
Advanced chemical engineering that is quite unique is used in the diaphragm. In a
colla orative development with Professor I.W. Ward a material that is superior to
all current alternatives has een realised. Produced from a woven Isotactic polymer
this leading edge technology provides for the most ideal diaphragm material. The
high quality reproduction is superior to all our current ench marks.
The Tactic® motor system development program was greatly accelerated as a
result of our in house CAD CAM facilities. Despite this capa ility (unique in the
U.K.) the development of the motor has een lengthy.
We started out with the “nothing is new under the sun” approach and su sequently
took a retrospective look at loudspeaker developments. One of the most nota le
products was the Alnico magnet driver which was always noted for its superior
performance in the mid range. Our research studied this phenomenon as a possi le
alternative ut it soon ecame clear that the difference was attri uta le not to the
type or qualities of the Alnico magnetic material ut ecause of the small diameter
and as a corollary small reflective shadow. Because out of phase energy cannot e
reflected ack through the cone, much lower levels of distortion are achieva le. The
rearward traveling sound waves pass into the enclosure unimpeded from here the
enclosure takes on responsi ility for dealing with this unwanted energy.
Transmission of these out of phase reflections through the cones is quite normal in
conventional ferrite systems where large in efficient magnets must e used. The
distortion, smearing and oxy sound that is accepted is nota le y its a sence in the
technology of The Tactic®
Although The Tactic ® is in fact half the physical size and mass of the Scan
enchmark used y Wilson Benesch and so many others to date, it is in fact almost
50% more powerful. Such an increase in performance is no mean achievement. It
provides the amplifier with that much more control of the diaphragms movement.
It provides greater control over the diaphragm, eing a le to accelerate and
decelerate it more effectively. This powerful motor provides dramatic improvements
in all measurea le parameters relating to control.
The basket has een developed from first principles. Natural forms are evident as
one can see, very different from the crude structures accepted y the “state of the
art” to date. Refined on CAD CAM and tuned exactly to our needs it delivers the
primary function of high stiffness ut uniquely, without restricting the movement
of air ehind the diaphragm which is considera le, particularly ehind the low
frequency drive systems. Nota ly there are no flat resonant sections. The curved
organic form is created on CNC tooling to exacting tolerances and accuracy. They
are machined from a single illet of aluminium and are incredi ly stiff.
The Wilson Benesch asket is an important technological advance. It provides us
with the all important performance advantage that makes the difference etween a