What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





Technics SB-T40 loudspeakers


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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