B&W 603 S3 Loudspeaker Lab Report

Lab Report

The stunning standard of finish debuted in the S2 Anniversary [HFN Jan '21] is continued in the 603 S3 pictured in these pages, alongside a boost to both the loudspeaker's sensitivity – up from 88.6dB to 89.7dB/1kHz/1m courtesy of 700 series motor assemblies – and the control over its forward response [see Graph 1, below]. The S2 Anniversary's 1.5kHz-3.5kHz trough and notch at 6kHz are now traded for an essentially flat but undulating trend with reduced ±3.8dB and ±3.9dB response errors that bears more than passing resemblance to that seen from the 803 D4 [HFN May '23] and 703 S3 [HFN Mar '23]. Pair matching is a spectacular 0.45dB (200Hz-20kHz) while the grille exerts little change to the trend [blue trace, Graph 1].

The new titanium dome tweeter has an almost identical +15dB/35kHz primary resonance [pink shaded area, Graph 1, and CSD waterfall, Graph 2] as the alloy 'double dome' of the S2 models but with a –6dB dip at 20kHz and ultimate extension of 48kHz (–6dB re. 10kHz). Distortion is a little higher here too (0.35% vs. 0.1%) but the Continuum cone midrange offers a far lower 0.04% (all 90dB SPL/1m). Distortion is also a low 0.4% through the bass where the two 165mm pulp drivers work over a 57Hz-250Hz (–6dB) bandwidth, supplemented by the rear-facing port at a 'peaky' 22Hz to deliver a diffraction-corrected extension of 40Hz [green shaded area, Graph 1]. Once again, however, the amplifier load is fairly tough – a minimum of 2.85ohm/113Hz coupled with relatively large swings in impedance phase from –72°/64Hz to +50°/1.3kHz, all resulting in a low EPDR of 1.07ohm/88Hz. PM


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

B&W 603 S3_Waterfall_R_50dB

Y scale is increased here to reveal 35kHz treble dome resonance. In-band modes are well-controlled

Sensitivity (SPL/1m/2.83V – 1kHz/Mean/IEC) 89.7dB / 88.7dB / 87.2dB
Impedance modulus: minimum & maximum (20Hz–20kHz) 2.85ohm @ 113Hz, 27.7ohm @ 52Hz
Impedance phase: minimum & maximum (20Hz–20kHz) –72° @ 64Hz, 50° @ 1.3kHz
Pair matching/Resp. error (200Hz–20kHz) 0.45dB/ ±3.8dB/±3.9dB
LF/HF extension (–6dB ref 200Hz/10kHz) 40Hz / 48.3kHz/48.2kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 0.4% / 0.04% / 0.35%
Dimensions (HWD, no plinth) / Weight (each) 985x190x340mm / 28kg
Price £1999

B&W Group Ltd
West Sussex
Supplied by: B&W Group Ltd
0800 232 1513