Напольная акустика — Technics SB-G90M2

The SB-G90M2 is a passive floorstanding speaker in the Technics Grand Class range and replaces the earlier SB-G90. Technics revised its mechanical parts and driver design, using extensive computer analysis to lower distortion, while keeping the point-source and linear-phase concept of its coaxial speakers. It is sold per piece at USD 3,999.99 in the USA and EUR 2,699 in Germany, finished in black.

Key specs that matter

Four drivers share the work in a ported three-way layout. A coaxial unit places a 25 mm dome tweeter in the centre of a 160 mm aluminium midrange cone, and two 160 mm woofers of the same diameter handle the bass. Crossover points sit at 500 Hz and 3.4 kHz. Technics quotes a range of 33 Hz to 90 kHz measured at -10 dB, a nominal impedance of 4 ohm, and sensitivity of 86 dB for 2.83 V or 83 dB for 1 W at 1 m. Rated input is 100 W under IEC rules with a 200 W maximum, and the suggested amplifier power spans 40 to 200 W. Each cabinet stands 1,114 mm tall including spikes, is 292 mm wide and 366 mm deep, and weighs about 35 kg.

Engineering and use context

Technics calls the coaxial unit an Advanced Phase Precision Driver. A Linear Phase Plug in front of the tweeter prevents phase disturbance at high frequencies, and the shallow Smooth Flow Diaphragm of the midrange reduces reflections off the cone surface for the dome at its centre. Computer analysis was used to cut self-resonance in this driver. Inside, a patented Standing Wave Termination Structure - a multiply-folded waveguide - absorbs standing waves, and further bracing stiffens the enclosure. Balanced Driver Mounting Architecture runs from the driver baffle down to the base plate so that driver vibration is carried away and dissipated. Supplied parts include spikes, spike shoes, rubber feet, wire bridges, a front cover and a cleaning cloth.

Pairing

A low impedance and modest per-watt efficiency call for a transistor design able to supply ample current into low loads, inside the power window Technics gives. Two pairs of solid screw terminals allow bi-wiring or bi-amping, so the woofers can be driven by one amplifier channel and the coaxial unit by another. In such a split setup the woofer channel only has to handle the band below the lower crossover point, while the second channel feeds the coaxial unit above it.

Alternatives

The Technics SB-R1 from the Reference Class is a larger floorstander with four 6.5-inch woofers and a flat coaxial midrange and tweeter rated to 100 kHz at -16 dB.