Loudspeakers

A key difference between the 702 S2 Signature and the new 702 S3 Signature is the re-engineering of the former’s rear-facing port into a down-facing position, low bass now flowing out across the surface of the S3’s stabilising plinth. The S2’s port was tuned to 21Hz while the S3’s far larger ‘Flowport’ is tuned to an even lower 16Hz (!) but suffers significant pipe resonances, absent in the S2, at 275Hz and at 530Hz. This aside, the port combines with the peak 93Hz output of the three 165mm ‘Aerofoil Profile’ woofers to yield a diffraction-correction bass extension of 42Hz (–6dB re. 200Hz).

The irregular-looking forward response measured on B&W’s preferred midrange axis [see Graph 1], is almost identical to that seen from the S2 – the dip at 1kHz sharper still [Graph 1 and 2] – but the notch at 16kHz has been erased thanks to the S3’s new tweeter mesh. While the 1kHz ‘kink’ remains, the Continuum mid cone resonance identified in the S2 at ~4kHz is suppressed and shifted upwards in the S3, while the CSD waterfall [see Graph 2, below] and main response still highlight the primary resonance of the ‘carbon’ dome tweeter at a high 48kHz/+7dB [pink shaded area, Graph 1]. The full-length grille is exceptionally transparent [blue trace, Graph 1], but the ±3.8dB response errors are obviously ‘intentional’ because the pair matching is so tight at 0.6dB (all 200Hz-20kHz, or 0.3dB from 200Hz-10kHz). The high 89dB/1kHz sensitivity is retained in the S3 but the loading is still quite tough – an impedance minimum of 2.9ohm/670Hz and 3.2ohm/111Hz is met with a negative (–64o/66Hz) phase angle and moderately taxing, worse case EPDR of 1.25ohm/86Hz.PM

Response inc. nearfield summed drivers/port [green], freefield corrected to 1m at 2.83V [yellow], ultrasonic [pink]. Left, black; right, red; w. grille, blue

The ~1kHz response notch [see Graph 1] is also seen here but mid driver resonances are reduced.