Technics SB-6A

Commentary

This 3-way speaker system improves power linearity by adopting a special shape linear damper and a new magnetic fluid in addition to the honeycomb diaphragm.

Each speaker unit uses a honeycomb flat diaphragm that is light and highly rigid.
This diaphragm has a planar structure using an aluminum alloy-made honeycomb structure in order to obtain accurate piston motion while eliminating air resonance (front chamber effect) generated in the cavity in front of the cone of a cone-type speaker. Rigidity is 1,000 to 1500 times that of a paper cone. There is no distortion due to deformation caused by Dainyu force, or characteristic degradation due to aging or temperature change.
In addition, in order to solve the problem that a part that does not move at all (= node) at a specific frequency occurs when the center of the flat diaphragm is driven, we have adopted a node drive that drives by connecting a voice coil to the node. In addition, in order to cope with the problem that the appearance of nodes differs depending on the shape and frequency of the diaphragm, we have developed a unique axisymmetric honeycomb that increases the density of the honeycomb toward the center. By eliminating the difference in strength between the left and right sides, the node is made into a perfect circle, and node drive with one circular voice coil is possible.

A 25 cm honeycomb planar woofer is installed in the low range.
This woofer uses an original linear damper to improve power linearity in the low frequency range.
Since this damper supports the linear motion of the voice coil more than 10 times the force of the normal damper, it minimizes the occurrence of rolling and improves the linearity even under the Dainyu force. The power linearity is approximately 3 times that of the normal damper.
A large and powerful magnet with a diameter of 145 mm and a weight of 1 kg realizes high efficiency. The voice coil bobbin is made of laminated polyimide resin film, and combined with the polyamide voice coil, it is designed to withstand high temperatures of 250 ℃.
In addition, this unit capable of piston motion up to 3 kHz was crossed over at 900 Hz to provide ample design.

It is equipped with 8 cm honeycomb plane type skoker in the middle range, and realizes wide-band piston motion reproduction up to 10 kHz by the unique node drive. The edge part adopts down roll edge and edge cover, and the cavity composed of these two is utilized to cancel the secondary resonance of the diaphragm.
In addition, the air gap between the voice coil and the pole piece has been narrowed as much as possible to achieve high efficiency. In addition, high input resistance has been obtained by the use of a polyimide film voice coil bobbin and a high heat-resistant voice coil.

A 2.8 cm honeycomb plane type tweeter is mounted in the high range.
In this tweeter, a magnetic fluid is filled in the space between the voice coil, pole piece and yoke, and the heat generated in the voice coil is released to the pole piece and yoke with a large heat capacity. This greatly improves the heat radiation effect. As a result, high input resistance is obtained, impedance is stabilized, and excellent power linearity is obtained. In addition, the magnetic fluid acts as a damper to suppress unnecessary low frequencies, and the low frequency resonance of the tweeter is suppressed to 1/3 to 1/4 of conventional ones.
The magnetic circuit with high magnetic flux density of 17,500 gauss realizes high efficiency, and the special shape equalizer on the front of the tweeter flattens the frequency characteristics.

A low-distortion network using a large choke coil is used in the network section. The choke coil in series with a woofer uses a large ferrite core with a self-fused wire of 1 mm diameter with low DC resistance to improve the distortion factor and sound quality at the time of Dainyu force.
In addition, a metallized polyester film capacitor with superior high-frequency characteristics has been adopted to improve both performance and reliability.

The tweeter is equipped with a thermal relay protection circuit to prevent unit breakage due to excessive input or abnormal signal.
The indicator lights when the thermal relay is activated, and the reset button on the front panel allows one touch restoration.

Independent attenuators are mounted on the tweeter and skoker respectively.

The enclosure uses a bass reflex system and an integrated bass reflex port that does not expose standing waves in the enclosure.
In addition, vibration analysis is carried out by the finite element method with the introduction of a computer, and unnecessary vibration is reduced by providing effective reinforcement. In addition, 3-way Z-frame, which is resistant to aging, is adopted for the wooden frame.

Model Rating

Method	3-Way, 3-Speaker, Bass reflex system, Bookshelf Type
Unit	For Low Band : 25 cm Flat Type For Middle Area : 8 cm Flat Type For High Frequency : 2.8 cm Flat Type
Frequency characteristic	33 hz to 35 khz -16dB 43 Hz to 33 kHz -10dB
Output sound pressure level	93dB/W/m
Impedance	6 Ω
Allowable input	160W(Music) 80W(Din)
Crossover frequency	900 Hz, 3.5 kHz
External dimensions	Width 350x Height 606x Depth 323 mm
Weight	16.0kg