THIEL
Model CS7.2
Coherent
®
Source
loudspeaker
system
OWNER INFORMATION
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Speaker of the Millennium
®
CONSUMER ELECTRONICS SHOW
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DESIGN PHILOSOPHY
The CS7.2 is a precision
instrument designed to translate,
as accurately as possible,
electronic information into
musical sound. All our efforts
have been directed toward
achieving extremely faithful
translation of all tonal, spatial
and dynamic information
supplied by the amplifier.
The CS7.2 is not intended to
mask or mitigate shortcomings
of the recording or other
components in the music
playback system.
We believe this approach is
the only way to provide the
potential of experiencing all the
subtle aspects that help make
reproduced music a most
enjoyable human experience.
Jim Thiel
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POSITIONING THE SPEAKERS
Because of their unipolar radiation pattern and co-axial design, the CS7.2s will provide good results when placed in
a variety of room locations. However, speaker placement will affect the accuracy of timbre, spatial performance, and
bass performance. Here are some guidelines to help you achieve the best sound from your speakers. (The pointed
metal stabilizer pins should not be installed until the final positioning has been determined.)
All aspects of speaker placement are dependent on the particulars of the room. Since every room is different, no
hard rules can be given, and experimentation is necessary to achieve the best results.
Distance from walls
Direct sound
Reflected sound
The CS7.2s, like most speakers, sound best if
Difference in arrival times
they are placed well away from all walls. Such
placement optimizes imaging characteristics,
and musical timbres are reproduced with the
least coloration because the initial sound
coming from the speaker is distinctly separated
in time from the secondary sound of wall
reflections. If reflections are heard too soon
after the primary sound, the brain tends to
interpret them as part of the initial sound,
causing the perceived timbre to be altered and
the spatial characteristics to be confused.
Figure 1 illustrates the problems caused
Figure 1. Early reflection problems caused by speakers placed
too close to side walls
by early side wall reflections. Sound waves
from the loudspeakers radiate both forward,
toward the listener, and laterally, reflecting off
side walls. When the speaker is placed too
close to side walls, the difference in arrival
times of the primary sound waves and the
reflected sound waves is too short for the brain
to discriminate between them.
Direct sound
Reflected sound
Difference in arrival times
Figure 2 illustrates the advantages of
placing the loudspeakers farther from side
walls. The arrival times of the primary, forward
radiating sound waves and the secondary,
reflected sound waves are well separated,
providing the proper delay needed for faithful
tonal and spatial reproduction.
There will also be a noticeable improve-
ment in openness when the speakers are even
two feet from the rear wall instead of one. If
Figure 2. Optimum placement for reducing reflection problems
possible, we prefer the speakers at least three feet from the rear wall and at least five feet from the side walls. Also,
it is not desirable for large objects to be placed very near the speakers since these will also be a source of unwanted
early reflections that reduce imaging accuracy.
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Spacing
Because of their very wide, even dispersion of energy, the CS7.2s can usually be placed farther apart than most other
speakers. Optimum imaging is usually achieved when the speakers are almost as far apart as each speaker is from the
listener, although this will depend on the width of the room—narrow rooms require more narrow placement. If the
speakers are too far apart for the room, there will tend to be a “hole” in the middle of the soundstage; if they are too
close together, the image will be compressed and will not achieve optimum width.
Aiming
Depending on the room in which they are used, the CS7.2s can be aimed anywhere between straight ahead and
angled in so they point directly at the listener. Straight-ahead placement produces the widest, most natural
soundstage. However, if it is not possible to place the speakers the desired distance from side walls, a toed-in position
will reduce the strength of side wall reflections and, in these cases, provide a more focused spatial presentation.
Bass
In general, when a speaker is close to a wall, the bass response is stronger; placing a speaker in a corner will make it
even more so. The CS7.2s are designed to provide accurate bass when positioned away from all walls—the same
position that provides the best imaging.
Listener position
The CS7.2s provide broad dispersion of energy at all frequencies and therefore provide good results throughout a
large listening area. Best imaging is provided for a listener centered in front of the speakers. Optimum accuracy of
timbre and depth perspective is provided only for a seated listener who is eight or more feet away from the speakers.
Placement suggestions
14'
Some people have restraints on speaker placement
because of room size, shape, or aesthetic considerations
2.5'
2.5'
and cannot meet one or more of the above placement
recommendations. They should not be discouraged from
investing in CS7.2s. It is our opinion that due to their
unipolar, point source radiation pattern, their very even,
wide dispersion, and the co-axial mounting of the tweeter
and midrange drivers, the CS7.2s fare better under
difficult circumstances than most other high quality
speaker systems. To help with placement, the following
suggestions are given as a starting point for a variety of
rooms.
3'
3'
8'
Figure 3 shows an average size room. Generally, it is
best to start with short wall placement. This arrangement
provides sufficient space behind the speakers, allows the
listener to be far enough away from the speakers, and still
maintains some distance between the listening position
and the wall behind the listener. Since the speakers may
be near side walls in order to keep spacing between the
speakers wide, toeing-in the speakers is suggested.
8-10' Listening Distance
Figure 3. Average listening room
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18'
10'
Some rooms, especially narrow ones, can
benefit from placing the speakers along the
long wall. Although space behind the
speaker and behind the listener is reduced,
this positioning increases the space
1'
1'
4'
4'
between the speakers without side wall
interference, and can improve overall
performance. Figure 4 shows the same
average size room as Figure 3, but with
long wall placement. The speakers should
be at least a foot from the rear wall, but the
amount of toe-in can be adjusted, along
with listener position, as well as the amount
of spacing between the speakers.
14'
8-10 ' Listening Distance
In a larger room, the optimum posi-
Figure 4. Average listening room with long wall placement
tioning suggestions on pages 2 and 3 are
easier to implement. Figure 5 shows one
set-up with the speakers five feet from the
side walls, three feet from the rear wall,
and the speakers aimed straight ahead. This
arrangement provides an ample amount of
space around the speakers to reduce
18'
3'
3'
5'
8'
5'
unwanted reflections and should give
excellent spatial performance and a very
“open” sound. Other placement options in
this room include: wider spacing between
the speakers, adding toe-in as the spacing
increases; increased space between the
speaker and the back wall to improve
imaging depth. Various listening position
distances can also be tried.
25'
8-12' Listening Distance
As mentioned at the beginning of the
positioning section, all rooms are different
and no hard rules can be given. Even rooms
with similar dimensions can have differ-
ences in wall, floor and ceiling construction
that greatly affect the sound. Also, “live”
rooms with hard surfaces, glass, and little
damping sound much different from “dead”
rooms with heavy carpet, drapes and plush
furniture. In other words—EXPERIMENT.
Figure 5. Large listening room speaker placement
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CONNECTING THE SPEAKERS
The CS7.2s’ input terminals are located on the bottom of the speaker near the back. Access is from the back with the
speaker in its normal upright position. Make sure that both connections are tight. It is best to turn the amplifier off
while connecting or disconnecting the speakers.
For proper performance, all speakers in the system must be wired in the same polarity. The speaker input
terminals are color coded for this purpose. The wire connected to the positive input terminal of each speaker,
marked with a red band, should be connected to the corresponding positive (+) output terminal of the amplifier. The
wire connected to the negative input terminal of each speaker, marked with a black band, should be connected to the
corresponding negative (–) output terminal of the amplifier. The speakers should be connected to the amplifier with
high quality cable to ensure minimal loss of power and proper control by the amplifier. If the speakers are being
connected to a vacuum tube amplifier with various impedance taps, the 4 ohm tap will probably give the best results.
Due to European CE regulations that do not permit banana plug type loudspeaker connections, we ship THIEL
speakers with removable plugs installed in the ends of the binding posts. If you wish to use banana plug type
connections, you may remove the black plastic plug inserted into the end of each metal binding post cap. To remove
the plug, use your fingernail to pry along the bottom edge of the plastic insert and lift out.
Bottom View
STABILIZER PINS
The speakers should be positioned before the stabilizer pins
installed.
Speakers positioned on a soft or uneven surface are able
rock slightly and will vibrate in reaction to forces the speake
generates to move the driver diaphragms. (Every action has
equal and opposite reaction.) This motion slightly reduces th
music’s clarity.
To eliminate this effect, the CS7.2s can be used with fo
Stabilizer Pins
metal stabilizer pins on uneven surfaces or on carpeted floor
provide a more solid footing. The points penetrate the carpet
allowing the speaker to couple more firmly to the floor. If th
use of pointed pins is not desired on hard surfaces, the metal
sockets will provide some stabilization.
THIEL
®
Two people are required to safely install the stabilizer p
Coherent Source
LOUDSPEAKER
MODEL
CS 7.2 S/N
To install:
• Position the speaker in the desired location.
MANUFACTURED BY:
THIEL Lexington, Kentucky USA
• Tilt the speaker forward slightly so that the back of the
speaker is a few inches off the floor.
Input Terminals
• Screw one pin into each of the two holes at the back
corners of the base. The pins should be screwed into the speaker until there is about 1⁄4" of thread remaining visible.
• Let the back of the speaker down and then tilt the speaker backward slightly so that the front is a few inches
off the floor and install the two front feet.
• With all four feet installed, the height of each foot should be adjusted so that the speaker stands firmly on the
floor without wobbling.
Please be cautioned that the stabilizer pins can be dangerous if not used with care. They will dent or punc-
ture hardwood floors and it is possible to damage carpets if the speakers are moved with the pointed feet in place.
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BREAK-IN
The CS7.2s, like most speakers, require a period of playing before they perform optimally. The time required
depends on how loudly the speakers are played; more time is required if played softly, less if played loudly. At least
50 hours at moderately loud levels are required before the speaker is performing near optimum. You should notice
even more improvement after 100 hours of playing.
ASSOCIATED EQUIPMENT
The CS7.2s are very high quality sound reproducers and will benefit from use with the finest associated equipment.
Because the speaker presents a lower than average load to the amplifier, an amplifier with high current capability is
recommended. The amplifier should be specified to provide twice the power into a 4 ohm load and at least three
times the power into a 2 ohm load as it provides into an 8 ohm load. Since the CS7.2s are extremely accurate
transducers, they will reveal distortions or non-linearities generated anywhere in the system. Also, the quality of the
interconnect and speaker cables will significantly affect the performance of the system.
POWER REQUIREMENTS
When selecting speakers, the second most commonly asked question by prospective buyers is “how much power do I
need?” This question does not have the simple answer most people expect because it is determined by more than just
the loudspeaker’s efficiency.
The first thing to keep in mind is that sound quality is usually much more important than sound quantity. There
can be large differences in the sonic performance of two amplifiers of equal power, and a smaller powered amplifier
can sound superior to a larger powered amplifier. Almost everyone will be happier with a 50 watt amplifier of high
sonic quality than with a 200 watt amplifier of mediocre sonic quality. For this reason, we feel there is no substitute
for listening to make your amplifier decision.
There are three almost equally important factors that determine how much power is needed for a given situation.
In order of importance they are:
1. The volume level desired
2. The speaker’s efficiency
3. The size of the room. Each of these factors can make a 10-to-1 difference in the power required.
In the real world, if all 3 factors are average, about 50 watts/channel is required. Each factor can raise or lower
this amount by a factor of about 3. Average values for each are:
- a volume level of 88dB SPL
- speaker efficiency of 87dB/W-m
- a room size of 3000 cu ft
The first factor is the most difficult to analyze or objectively determine. There are different ideas about what is
“loud.” Some people do not want to play music above a sound pressure level of 88dB and some do not want to play
music below 88dB. Usually, people who like to listen only at low levels can decrease their power by a factor of 2.
People who like music at very loud levels, even if only occasionally, should increase their power by 2 times or more.
A speaker with a low 84dB/W-m efficiency will require twice the power of an 87dB speaker, and one with a high
rating of 90dB/W-m will require only half the power of an average speaker. Usually, high efficiency can be obtained
only by trading off sonic quality—there are very few speakers that provide a very high level of both. THIEL speakers
are of average efficiency and therefore require an average amount of power.
A small room will need less power for a given loudness level than a large room. A very small room of 1000 cu ft
(11 ft x 11 ft with an 8 ft ceiling) will usually require only half the power of an average room. A large room of
6000 cu ft (20 ft x 30 ft with a 10 ft ceiling) will usually require twice the average power. If the listening room is
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connected to another room by a large open area, the required power will increase—but not by the amount of the
combined room volume. If the room has a “dropped” ceiling with lightweight panels, the ceiling will be almost
transparent acoustically. In this case the space above the ceiling should be added. If the panels are heavy they will
act more like a solid ceiling.
With all this in mind, a person who likes to play music only at lower levels, has a small room, and who has
fairly efficient speakers can get the performance desired with only 20 watts; whereas, a person who sometimes likes
to play loudly, has low efficiency speakers, and a large room may need 300 watts.
It is important to have enough power to play at the volume level you desire without distortion. If you play the
speakers more loudly than the volume the amplifier can cleanly produce, the amplifier will produce overload
(clipping) distortion. The sound will become compressed, strained, and in extreme cases, obviously distorted. This
distortion is actually non-musical additional energy and since it is concentrated in the high frequency region where
the speaker is least able to handle it, the tweeter’s voice coil can be burned in extreme cases. Driver damage in
general is usually the result of having inadequate power rather than having too much. If your system does not play
as loudly as you would like without becoming distorted, you need a more powerful amplifier.
Remember that how loud your system plays has nothing to do with the position of your volume knob. Source
components such as CD players and tape decks, as well as recordings themselves, can all have different output
levels. This means that to achieve the same volume level for each source, your preamp’s volume control may need
to be set at a different position for each source. For example, when some high output CD players are used with
lower power amplifiers, clipping can be reached with a volume knob setting as low as 4 on a scale of 10.
SERVICE
If your CS7.2s require service, please contact your authorized THIE L dealer. Factory service information and
technical support is available by calling 606/254-9427, Monday–Friday, 8:30 a.m.– 5:00 p.m. Eastern Time. Our
service e-mail address is [email protected].
CABINET FINISH CARE
THIEL wood cabinets possess a high quality lacquer finish that is both beautiful and durable. However, any wood
finish can be damaged by excessive moisture, dryness, or direct sunlight. When cleaning your speakers, avoid using
oils, waxes, or polishes that contain silicone, such as Pledge
or Johnson’s. We recommend using Endust. Non-wood
laminate cabinets may be cleaned with a glass-type cleaner
and a soft cloth.
GRILLE
The CS7.2 grille is designed to not produce diffraction so
there is no sonic reason to remove it. If you do need to
remove the grille, pull the bottom of the grille frame away
from the speaker an inch or so and then lift the grille
upward to remove it. When replacing the grille, first push
the top down onto the baffle and then push the bottom back.
The grilles can be cleaned of dust by using an upholstery
attachment of a vacuum cleaner. To prevent damage to the
tweeter, take care not to push the cloth in toward the top of
the grille.
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CS7.2 SPECIFICATIONS
Bandwidth (–3dB)
23 Hz-20 kHz
25 Hz-17 kHz ±1.5 dB
minimum ±10°
Amplitude Response
Phase Response
Sensitivity
86 [email protected] V-1m
Impedance
4 ohms (3 ohms minimum)
100-500 watts
Recommended Power
Size
11" W x 19" D x 55" H
168 pounds
Weight
We Want You Listening For A Lifetime
Used wisely, your new sound equipment will provide a lifetime of enjoyment. Since hearing damage from loud
noise is often undetectable until it is too late, THIE L and the Electronics Industries Manufacturers Association
recommend you avoid prolonged exposure to excessive noise. Depending on room size and amplifier power, some
home audio systems can reach sound pressure levels in excess of 95 decibels with peaks of over a 105 decibels. For
your protection, the list below identifies sound levels for various noises.
Decibel
Level Example
The Following Noises Can Be Dangerous
Under Constant Exposure
30
40
Quiet library, soft whispers
90
100
120
140
150
Subway, motorcycle, truck traffic, lawn mower
Garbage truck, chain saw, pneumatic drill
Rock concert in front of speakers, thunderclap
Gunshot blast, jet plane
Living room, refrigerator, bedroom away from
traffic
50
60
70
80
Light traffic, normal conversation, quiet office
Air conditioner at 20 feet, sewing machine
Vacuum cleaner, hair dryer, noisy restaurant
Average city traffic, garbage disposals, alarm
clock at two feet
Rocket launching pad
Information courtesy of the Deafness
Research Foundation and the EIA.
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LIMITED WARRANTY
THIEL warrants every THIEL model CS7.2 system against defects in materials
and workmanship to the original owner for a period of ten years from the date of
purchase. THIEL will, at no charge, replace any defective part and make any
repairs necessary to ensure its proper performance when the defective unit is
returned to us postpaid.
This warranty does not cover damage due to accident or abuse and is void if
the unit has been tampered with.
This warranty is automatic and no registration is required. This warranty gives
you specific legal rights. You may also have other rights which are particular to
your state.
The following information is for your records.
Serial Numbers______________________________
Purchase Date_______________________________
Purchased From_____________________________
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CONTRIBUTOR
HARDWOOD
FORESTRY FUND
THIEL
1026 Nandino Boulevard
Lexington, Kentucky 40511-1207
3/01
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