Flatter Your Ears
But it takes more
than an inventive new enclosure to build a speaker for the future - after all,
it's what's inside the box which ultimately determines what comes out. And
that's where Technics engineers really concentrated their efforts. The result
is the honeycomb disc driver.
Why Flat is Better
The tradiional
speaker driver is shaped like a cone - and it sufers from an inherent form of
distortion called the cavity effect. All cone drivers are prone to the cavity
effect, which results from sound waves colliding with each other as they
emanate from the diaphragm surface. The resulting standing wave distortion
caauses peaks and dips in the frequency response and degrades sound quality.
The only way to defeat the cavity effect is to eliminate the cavity - that is,
to construct a flat diaphragm. Which brings us to the Technics honeycombdisc.
Not only is it flat but it is also axially symmetric - it is equally rigid at
all points and in all directions. And it featurs nodal drive, which
substantially eliminates partial vibrations and assures a wide range of
pistonic diaphragm motion.
The Technics
honeycomb features an ideal combination of rigidity and flexibility. It is fast
enough to respond to delicate nuances in the high range, yet strong enough to
avoid partial vibration.
Plus, the flat
driver means inherent phase linearity, since all the acoustic centers are
aligned in the same plane. Once, we had to stagger the drivers to achieve phase
linearity. But with today's honeycomb disc technology, the drivers can be
mounted on the same baffle without sacrificing linearity.
Theory into
Praactice- Honeycomb Drivers
Woofer
The SB-T40 features
a 22 cm (9"woofer} low frequency driver. The woofer are powered by large
magnets with high output and use voice coil designed for linear response.
A carefully
formulated polyamide adhesive secures the voice coil and the polyimide film
bobbin is fiber reinforced - together, they can withstand extreme temperatures
of 250°C. the result is excellent power handling characteristics.
Midrange
Efficiency and
smooth response - thes are the desired
traits of a midrange driver. Technics uses the same heat-resistant materials
that the woofer features in the midrange, to improve power handling. The cloth
edge construction ensures wide, smooth response, while narrow magnetic gaps in
the voice coil yield highly efficient operation.
Tweeter
If a tweeter can
maintain response all the way up to 35 kHz, you can believe that high range
response is outstanding. Technics uses a magnetic fluid in the circuit gap and
a precision acoustic equalizer to achieve this remarkable upper frequency limit
- thay also contribute to good heat dispersion, high power handling, and a
stable stereo image not limited by "beaming".
Thermal Relay
Protection
It's not easy to
overload the SB-T40 - but protection is essential, particulrly if the amp or
source material creates or exhibits distortion. Under these adverse conditions,
overheating could conceivably damage the speaker. So,Technics included a
thermal relay protection circuit, which cuts power at the input terminals if an
abnormal temperature rise does occur. It is easily resettable using a front
panel button, and an LED illuminates to confirm the protection circuit;s
operation.
Other Features
Computer designed
high density particle board enclosure
Low distortion, low
crosstalk crossover networks.
Strong, easy-to-use
screw-in type speaker cord connection terminals.
Detachable grille
Tweeter level
control
Specifications
Configuration
Type: 3-way, 3-speaker bass-reflex
Driver Units:
Woofer 220 mm
(9") honeycomb disc
Midrange 52mm
(2") honeycomb disc
Tweeter 28 mm
(1-1/8") honeycomb disc
Impedance: 8 Ω
Input Power: 91 W music ( 60 W DIN)
Output Level: 90 dB/W/1m
Frequency
Response: 32 Hz - 38 kHz (at 16 dB below
average level)
40 Hz - 35 kHz (at
10 dB below average level)
Crossover
Frequency: 1,800 Hz and 3,500 Hz
Dimensions (W x H x
D): 285 x 830 x 255 mm (11-7/32" x
32-11/16" x 9-31/32")
Weight: 13,5 kg (29,8 lbs)
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