Technics SB-M2 Monitor2

Commentary

This is a 3-way monitor speaker system utilizing the know-how of the SB-M1, which pursues the best physical characteristics as a monitor speaker.

Each unit uses a honeycomb flat diaphragm developed by our own technology.
In the flat diaphragm speaker unit, the position of the sound source center is clearly determined in front of the diaphragm. Moreover, there is no deterioration of the frequency characteristics due to the front chamber effect that occurs in cone-type units, etc., and thus excellent phase characteristics are obtained.
This honeycomb flat diaphragm is characterized by its driving method. In general, when a flat diaphragm is vibrated in free space, a part (node) which does not move at all at a specific frequency appears. Driving at the node position cancels the resonance mode, greatly improves the piston motion range, and provides low-distortion frequency characteristics.
Technics uses a unique circular axisymmetric honeycomb core and realizes an ideal nodal drive with a single circular voice coil.

A 38 cm honeycomb plane woofer is mounted in the low range. This unit allows piston motion up to 2 kHz with a large diameter of 38 cm by the nodal drive.
It uses a specially shaped linear damper with vertically symmetric gathers arranged in four directions. It has 10 times more resistance to inclination than a normal damper, so it has excellent power linearity from the time of Oire force to the time of large input.
A large strong magnet with a diameter of 200 mm, weight of 3.1 kg, magnetic flux density of 14,800 gauss and total magnetic flux of 500000 maxwell is adopted to realize high efficiency. Polyimide GFRP is adopted for voice coil bobbin, and high input resistance design that can withstand high temperature of 250 ℃ is adopted.

Mid-range with 8 cm honeycomb planar mid-range
The diaphragm node is directly driven by a 50 mm diameter voice coil to achieve piston motion up to 10 kHz. A large magnet with a diameter of 140 mm and weight of 1.2 kg is used to achieve high efficiency.
In addition, the cavity composed of the edge part and edge cover is controlled to suppress the peak and dip of the frequency characteristic.

A 2.8 cm honeycomb flat tweeter is mounted in the high range.
The honeycomb core is a 0.9 mm-wide and 20 μ m-thick aluminum-alloy ribbon that is precisely processed into the floriform shape of chrysanthemum. The shape is unique to the tweeter with further improved directivity. In addition, laminated mica is used for the skin material of the core. The excellent characteristics of sound speed 6700m, specific gravity 1.9 and bending rigidity about 3 times that of aluminum realize a lightweight and highly rigid diaphragm.
In addition, a large magnet with a weight of 800g is adopted for higher efficiency, and a magnetic fluid is filled between the voice coil and pole piece to improve input resistance, thereby increasing heat radiation effect.

The network is divided into two sections, one for the woofer and the other for the tweeter mid-range. Each section is installed on the bottom of the enclosure and the other on the back of the terminal to prevent sound quality degradation due to mutual interference.
A ferrite core with low loss and low distortion is used for the choke core, and a choke coil with a wire diameter of approximately 1.6 mm is used for the woofer to minimize DC resistance.
A metallized polyester film capacitor with superior high-frequency characteristics is used for the tweeter circuit.

The enclosure is a bass-reflex type with an internal volume of 115L.
The material is 25 mm thick high-density particle board, and the weight class with a total weight of 50 kg eliminates adverse effects such as box rumbling.
There were 2 models, SB-M2-S with gray paint finish and SB-M2-M with wood finish using carefully selected walnut.

Model Rating

Type	3-Way, 3-Speaker, Bass reflex system, Bookshelf Type
Units Used	For low band : 38 cm honeycomb flat type For Middle Area : 8 cm Honeycomb Flat Type For high-frequency band : 2.8 cm honeycomb flat type
Playback frequency band	27 hz to 38 khz -16dB 35 Hz to 35 kHz -10dB
Output sound pressure level	92dB/W/m
Impedance	6 Ω
Allowable input	300W(MUSIC) 130W(DIN)
Crossover frequency	750 Hz, 4 kHz
Level control	Mid range, high range, continuously variable
External dimensions	Width 540x Height 820x Depth 415 mm
Weight	50.0kg