Wisdom STS User manual

Owner’s Manual
STS
High Output RTL®Subwoofer

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Table of Contents
Introduction | 5
Overview | 5
Unpacking the STS | 6
Placement | 7
Room Treatment | 7
Professional Acoustic Design | 8
References | 9
Setting Up the STS | 9
Making the STS Connections | 10
North American Warranty | 11
Obtaining Service | 12
Specifications | 13
Dimensions | 14
DOCUMENT CONVENTIONS
This document contains general safety, installation, and operation instructions for the Wisdom
Audio STS High Output RTL® Subwoofer. It is important to read this document before attempting to
use this product. Pay particular attention to:
WARNING: Calls attention to a procedure, practice, condition or the like that, if not correctly
performed or adhered to, could result in injury or death.
CAUTION: Calls attention to a procedure, practice, condition or the like that, if not correctly
performed or adhered to, could result in damage to or destruction of part of or the entire product.
Note: Calls attention to information that aids in the installation or operation of the product.

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Introduction
Congratulations on purchasing your Wisdom Audio subwoofer. The STS’s Regenerative
Transmission LineTM technology delivers tremendous bass performance in terms of
depth, dynamics, and distortion resulting in articulate bass that integrates seamlessly
with high-resolution main speakers such as Wisdom Audio’s Sage Series.
We recognize that setting up a Wisdom Audio High Output RTL® subwoofer can be a bit
more involved than connecting a common sealed or ported subwoofer, which is why we
recommend that our systems be engineered and calibrated by Factory Personnel
Overview
Your Wisdom Audio STS subwoofer uses a modern implementation of an old idea for
high quality, low distortion bass reproduction. While the roots of the Regenerative
Transmission LineTM go back to the 1950’s, it is the combination of modern computer
modeling and the vastly more powerful motors of contemporary driver design that
make the RTLTM so special.
There is a class of bass enclosures that has been around since the 1950’s, which can be
described generically as “low frequency tapped waveguides” or “tapped pipes”. It was
an idea that was a bit ahead of its time then, since fully optimizing its use required both
powerful drivers and computer modeling. But, if you are into such things, check out US
Patent 2,765,864 (filed in 1955), and an AES paper published in 1959, “Analysis of a Low
Frequency Loudspeaker System.”
We have utilized sophisticated modeling software to fully optimize our enclosures and
have developed drivers that are specifically optimized for this application. We call our
unique implementation of this relatively old idea a “Regenerative Transmission LineTM”
subwoofer, or “RTL” sub for short.
All dynamic drivers develop energy on both sides of the diaphragm, with the rear energy
being 180° out of phase with the front energy. If you allow the driver to operate in free
space (no enclosure), the front and rear energies largely cancel each other out –
especially at low frequencies.

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In our Regenerative Transmission Line TM subwoofer, the energy from the back side of
the driver is sent along a long, folded path in such a way that its lowest frequencies
arrive back at the front side of the driver in phase, effectively summing to an increase of
6 dB in output. Thus, the energy from both sides of the woofer cone is used in a
productive way, resulting in a substantial reduction in distortion and an effective surface
area double compared to what you would otherwise expect. As an example, the
effective radiating surface area of the two 15” woofers in the STS is equivalent to four
15” woofers in more conventional enclosures.
The results are quite stunning. Low frequencies are strikingly dynamic and responsive,
and integrate quite seamlessly with the fast and detailed Sage Series planar magnetic
hybrids. As an example, the STS is only -3 dB at 15 Hz and can output in excess of 130
dB at 20 Hz.
Unpacking the STS
The Wisdom Audio STS subwoofer is a substantial piece of equipment. Please exercise
caution when unpacking your STS to ensure that you do not strain yourself from its
(perhaps unexpected) weight.
CAUTION
Do not attempt to lift your STS by yourself. Unpacking this subwoofer is clearly a two-
person job. It is unwise for a single person to attempt doing so.
Do not attempt to lift your STS while bending or twisting from the waist. Use your legs
for lifting, not your back.
Always stand as straight as possible and keep the STS close to your body to reduce
strain on your back.

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Subwoofer Placement
Subwoofers offer somewhat greater flexibility in placement since the frequencies they
reproduce are not readily localizable by the human ear. This is because the wavelengths
they reproduce are more than ten feet (3 meters) long, but our ears are located only
about 6-7 inches (17 cm) apart. Thus, these extremely long waves do not contribute
meaningfully to the imaging that the main speakers create.
However, this fact does not mean that the placement of the subwoofers has no effect
on the sound quality in the room. Far from it. The subwoofers are the most likely to
suffer from the response irregularities introduced by the room itself, operating as they
do below approximately 80 Hz in most systems.
Recent research into the behavior of rooms as a function of speaker placement has
concluded that – if you have the freedom to do so – there are significant advantages to
placing several smaller subwoofers around the room, rather than relying on a single
large woofer. Moreover, the optimum placement is usually centered on each of the four
walls, or deep in the corners of the room. If you have the luxury of doing so, this simple
placement strategy can reduce the size of the room’s response irregularities from 20
decibels down to perhaps as little as 6-8 decibels – a tremendous improvement.
Reducing the room’s inherent problems to this degree provides a huge advantage.
Room Treatment
Rectangular rooms have six reflecting surfaces (four walls, ceiling, and floor)
that reflect sound to the listener, after various delays introduced by the indirect routes
the sound take on their way to the listener. These first reflections are particularly
damaging to sound quality. Looking at the simplest case of stereo reproduction, you
have a minimum of twelve first reflection points in your room that deserve some
attention.
Unfortunately, it is often difficult to do much about the ceiling and floor reflections,
even though they are arguably the most destructive. (The minimization of these
reflections is one of the strongest arguments for the tall, line source loud- speakers that
Wisdom Audio builds.) This leaves you with eight “first reflections” that you should
consider minimizing somehow. These points are easily found by having an assistant slide
a small mirror along the four walls of the room, while you sit at the listening position.

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Any place on the wall where you can see a reflection of any speaker is a first reflection
point. Concentrate on the first reflections for the Left and Right speakers first.
If you can, arrange to apply either absorption or diffusion at these eight points (don’t
forget the wall behind you). Absorption can be as simple as heavy, insulated drapes;
diffusion can be provided by a well-stocked bookcase with books of varied sizes.
Alternatively, you can buy purpose-designed room treatments (some sources listed
under References, below).
The important things to remember are these: a good room should have a balance of
absorption and diffusion; and if you are going to treat only a few areas of the room, the
first reflection points are the most important ones to treat.
Professional Acoustic Design
Does this all sound too complicated? For good reason: it is complicated.
The difference between the average listening room and one that is professionally
designed and implemented is huge. A great listening room will disappear to an
astonishing degree, letting the experiences captured in your recordings speak to you
directly. A well-designed room is also quieter and more comfortable. It can easily
become a favorite retreat for peace and rejuvenation.
If you decide to investigate the possibility of improving your room with the help of a
professional, it is important to find someone who focuses on residential spaces. Most
acousticians are trained to deal with large spaces – airports, auditoriums, lobbies in
commercial buildings, etc. The problems seen in “small” rooms (residential spaces) are
quite different, and outside the experience of most acousticians. Find someone who
specializes in and has a great deal of experience designing home studios, home theaters,
and the like. Your Wisdom Audio dealer may be such a person; failing that, he/she can
help you find such a professional.

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References
Books on Acoustics
The Master Handbook of Acoustics, F. Alton Everest, TAB Books
Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms by
Dr. Floyd Toole, Focal Press
Setting up the STS
There is no escaping the fact that the STS is a large subwoofer. That being said, it is
designed to have remarkable installation flexibility for something so large. It may be
used standing upright, or laying down on its broad side, in which case it can be built into
a set of risers or as part of a “stage” in front of the screen.
The STS also includes three locations for the exit of the Regenerative Transmission
LineTM. As shipped from the factory, the vent is located on the end of the STS
enclosure. However, if your location would be better served by the vent being on one
side or the other, your dealer can easily swap the grille for the solid aluminum plate that
covers the desired exit location. There is no difference in performance, but often a great
difference in application flexibility.
The STS is a passive subwoofer, meaning that it does not come with a “plate” amplifier
or internal crossover. The crossover function is normally provided by the surround
preamplifier in the system (which is a required part of any system that uses an STS).
Similarly, the amplifier is one channel of whatever is being used for the rest of the
system, or perhaps a dedicated, high power amplifier, depending on your application.
The sensitivity of the STS is quite high, at 101 dB/2.83V/1m (2.83V is one watt at 8Ω).
So you do not necessarily have to have a huge, powerful amplifier to drive the STS.
However, if you want to fill an unusually large space, the STS can handle 5000 watts of
power and deliver in excess of 130 dB at 20 Hz (again, measured at one meter).
We recommend using a Wisdom Series SA Amplifier for the best results, since the STS
sounds so good that you will be inclined to turn it up. You cannot go wrong by having
too much power.

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Making the STS Connections
As with any system, you should make changes to the connections only when the power
is turned off to avoid any chance of inadvertently causing a problem (such as a short-
circuit).
We recommend using heavy-gauge speaker wire, the gauge will vary dependent on your
speaker run length. Please consult an authorized dealer to determine what gauge would
be best for your application.
For the purposes of this manual, we will assume that you have already connected the
surround processor as per the instructions found in its manual. As such, you should have
signal coming from your source component(s) to a preamp/processor that provides bass
management (to create the subwoofer channel(s), the signal for the sub- woofer is sent
to a high-quality amplifier such as the Wisdom Audio SA Series amplifiers.
Connect the outputs of your amplifier to the subwoofer, taking care to get the polarity
correct. Connect the positive (+) terminals on your amplifier to the positive (+) terminals
on the STS; likewise, connect the negative (–) terminals on the amplifier to the negative
(–) terminals on the STS.

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North American Warranty
Standard Warranty
When purchased from and installed by an authorized Wisdom Audio dealer, Wisdom
Audio loudspeakers are warranted to be free from defects in material and workmanship
under normal use for a period of 10 years from the original date of purchase on the
cabinet and passive drivers.
IMPORTANT: Wisdom Audio loudspeakers are designed for installation and operation in
environmentally controlled conditions, such as are found in normal residential
environments. When used in harsh conditions such as outdoors or in marine
applications, the warranty is three years from the original date of purchase.
During the warranty period, any Wisdom Audio products exhibiting defects in materials
and/or workmanship will be repaired or replaced, at our option, without charge for
either parts or labor, at our factory. The warranty will not apply to any Wisdom Audio
products that has been misused, abused, altered, or installed and calibrated by anyone
other than an authorized Wisdom Audio dealer. 
Any Wisdom Audio product not performing satisfactorily may be returned to the factory
for evaluation. Return authorization must first be obtained by either calling or writing
the factory prior to shipping the component. The factory will pay for return shipping
charges only if the component is found to be defective as mentioned above. There are
other stipulations that may apply to shipping charges.
There is no other express warranty on Wisdom Audio products. Neither this warranty
nor any other warranty, express or implied, including any implied warranties of
merchantability or fitness, shall extend beyond the warranty period. No responsibility is
assumed for any incidental or consequential damages. Some states do not allow
limitations on how long an implied warranty lasts and other states do not allow the
exclusion or limitation of incidental or consequential damages, so the above limitation
or exclusion may not apply to you.
This warranty gives you specific legal rights, and you may also have other rights, which
vary from state to state. This warranty is applicable in the United States and Canada
only. Outside of the U.S. and Canada, please contact your local, authorized Wisdom
Audio distributor for warranty and service information.

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Obtaining Service
We take great pride in our dealers. Experience, dedication, and integrity make these
professionals ideally suited to assist with our customers’ service needs.
If your Wisdom Audio loudspeaker must be serviced, please contact your dealer. Your
dealer will then decide whether the problem can be remedied locally, or whether to
contact Wisdom Audio for further service information or parts, or to obtain a Return
Authorization. The Wisdom Audio Service Department works closely with your dealer to
solve your service needs expediently.
IMPORTANT: Return authorization must be obtained from Wisdom Audio’s Service
Department BEFORE a unit is shipped for service.
It is extremely important that information about a problem be explicit and complete. A
specific, comprehensive description of the problem helps your dealer and the Wisdom
Audio Service Department locate and repair the difficulty as quickly as possible.
A copy of the original bill of sale will serve to verify warranty status. Please include it
with the unit when it is brought in for warranty service.
WARNING: All returned units must be packaged in their original packaging, and the
proper return authorization numbers must be marked on the outer carton for
identification. Shipping the unit in improper packaging may void the warranty, as
Wisdom Audio cannot be responsible for the resulting shipping damage.
Your dealer can order a new set of shipping materials for you if you need to ship your
loudspeaker and no longer have the original materials. There will be a charge for this
service. We strongly recommend saving all packing materials in case you need to ship
your unit someday.
If the packaging to protect the unit is, in our opinion or that of our dealer, inadequate to
protect the unit, we reserve the right to repackage it for return shipment at the owner’s
expense. Neither Wisdom Audio nor your dealer can be responsible for shipping damage
due to improper (that is, non-original) packaging.

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Specifications
All specifications are subject to change at any time to improve the product.
•Number of required amplifier channels: 1
•Frequency response:20Hz – 80 Hz ± 2dB relative to the target curve
•Impedance:4Ω
•Sensitivity: 101 dB/2.83V/1m
•Power handling, peak: 5000w
•Maximum SPL: 130dB / 20 Hz /1m
•Dimensions: See appropriate dimensions drawings on next page
•Shipping weight, each: 350 lbs. (159 kg)
For more information, see your Wisdom Audio dealer or contact: 
Wisdom Audio
1572 College Parkway, Suite 164
Carson City, NV 89706
wisdomaudio.com
[email protected]
[phone]

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STS Dimensions

STS OM © 11/2021 Wisdom Audio, Inc. All rights reserved. Printed in U.S.A.
WISDOM and the stylized W are registered trademarks of Wisdom Audio.
Wisdom Audio1572 College Parkway, Suite 164
Carson City, Nevada 89706 USA
TEL [phone]
FAX [phone]
wisdomaudio.com