B&W 603 S2 Anniversary Edition Loudspeaker Lab Report

Lab Report

While the Anniversary ticket brings with it a stunning standard of finish, it's the 603's 'S2' acoustical revisions that are of greatest interest here. In practice, the forward response remains uneven [see Graph 1, below] although the 'shape' with its trough from 1.5kHz-3.5kHz and notch at 6kHz – also reflected in mild resonances seen on the CSD waterall [see Graph 2] – now almost precisely mirrors that of the reference 800 D3 [HFN Oct '16], albeit at a slightly lower 88.6dB/1kHz sensitivity. This is still bang-on B&W's own 88.5dB specification although the undulations from 1.5kHz-8kHz not only create some latitude in this measurement (86.9dB/500Hz-8kHz and 87.7dB/200Hz-20kHz) but are also responsible for a ±4.3dB response variation.

Pair matching is excellent, however, at 1.3dB (200Hz-20kHz) while the grille presents little adverse impact [cyan trace, Graph 1]. I discuss the +15dB/36kHz treble dome resonance [pink shaded area, Graph 1] in our boxout but at the other end of the spectrum B&W has engineered a fine 42Hz bass extension (–6dB/re. 200Hz) – its two 165mm bass drivers working across 57-470Hz (–6dB) while the rear-facing port has a clean but 'peakier' output at 24Hz [green shaded area, Graph 1].

Distortion is very low through mid and treble (typ. <0.1% re. 90dB SPL) courtesy of the upgraded passives and CC midrange and DDD treble units, but the loading will not be a walk in the park for all amplifiers. Specifically, there's a broad sub-4ohm trench from 87Hz-700Hz and a tough minimum of 2.85ohm/124Hz coupled with relatively large swings in impedance phase from –72o/66Hz (9.1ohm) to +51o/1.26kHz (7.5ohm). PM

221bw.lab1

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

221bw.lab2

Y scale is increased here to reveal 36kHz treble dome resonance. In-band modes are well-controlled

Sensitivity (SPL/1m/2.83V – 1kHz/Mean/IEC) 88.6dB / 86.9dB / 85.5dB
Impedance modulus: minimum & maximum (20Hz–20kHz) 2.85ohm @ 124Hz, 27.3ohm @ 53Hz
Impedance phase: minimum & maximum (20Hz–20kHz) –72° @ 66Hz, 51° @ 1.26kHz
Pair matching/Resp. error (200Hz–20kHz) 1.3dB/ ±4.3dB/±4.2dB
LF/HF extension (–6dB ref 200Hz/10kHz) 42Hz / 51.3kHz/52.8kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 0.45% / 0.05% / 0.1%
Dimensions (HWD) / Weight (each) 985x190x340mm / 24kg
Price £1499

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