Technics SB-F3 Loudspeaker Lab Report

Although this is the largest of the F series, its 321x179x191mm (hwd) cabinet is still very compact by the standards of modern standmount loudspeakers. However, and despite its IB/sealed box configuration, it still achieves a very creditable 89.0dB/1kHz sensitivity - bang on Technics' own specification for the SB-F3 - boosted still further by the bold mid/presence trend seen on the forward response [see Graph 1]. This is centred on the 3kHz crossover and lifts its averaged 500Hz-8kHz sensitivity still further to a quite astonishing 89.8dB. Of course, this 'brightened' mid/presence also contributes to the slightly wayward ±4.7dB and ±5.0dB response errors, respectively (re. 200Hz-20kHz), although the pair matching is a fine 0.8dB up to 15kHz above which some variance in the treble dome output stretches this to 1.9dB. The extension of the dome is just 22kHz but this is maintained well off-axis [grey trace, Graph 1] thanks to the uniform dispersion achieved by Technics' curved horn profile.

Neither will the SB-F3 tax your choice of amplifier with its minimum modulus of 3.6ohm (though closer to a 4ohm nominal than the rated 8ohm). This occurs at a high 7kHz, along with the largest +39o/-54o swings in phase angle at 4kHz-20kHz, so the toughest EPDR of 1.58ohm occurs at 5.25kHz where sustained musical levels are unlikely. At lower frequencies, the other dip in EPDR of 2.9ohm at 150Hz is equally manageable. The downside to this high sensitivity and ease-of-drive is its limited bass extension - the 160mm bass/mid driver peaks at 145Hz and has a diffraction-corrected limit of 80Hz (-6dB re. 200Hz). Boundary reinforcement from 'bookshelf' siting will extend this figure. PM

Above: Response including nearfield bass driver [green], freefield corrected to 1m at 2.83V [yellow], ultrasonic [pink]. Left, black; right, red; ±15o, grey


Above: A series of modes at 1Khz, 2Khz And 3Khz are seen, coinciding with the boosted response [Graph 1]

Sensitivity (SPL/1m/2.83V – 1kHz/Mean/IEC) 89.0dB / 89.8dB / 88.0dB
Impedance modulus: minimum
& maximum (20Hz–20kHz)
3.55ohm @ 6.98kHz
18.1ohm @ 90Hz
Impedance phase: minimum
& maximum (20Hz–20kHz)
–54o @ 4.01kHz
+39o @ 20kHz
Pair matching/Resp. error (200Hz–20kHz) 1.9dB/ ±4.7dB/±5.0dB
LF/HF extension (–6dB ref 200Hz/10kHz) 80Hz / 22.3kHz/22.9kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 6.5% / 2.2% / 0.55%
Dimensions (HWD) / Weight 321x179x191mm / 5kg
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