B&W 801 D4 Loudspeaker Lab Report

Lab Report

Rated at 90dB sensitivity, the new 801 D4 romps home with a very fine 89.7dB (1kHz) and 89.5dB (500Hz-8kHz). The forward response trend now has something of a +2dB 'step' between 100Hz-1kHz and 1kHz-20kHz [see Graph 1, below], resulting in errors of ±3.3dB from 200Hz-20kHz or ±2.2dB over a narrower 800Hz-20kHz. The principle 'features' are a 3dB dip at ~600Hz and an uplift in treble of ~4dB between 6-10kHz, the ultrasonic output being remarkably flat and extended over the next two decades [pink shaded area, Graph 1]. The magnetically-attached grilles offer precious little disruption [blue trace, Graph 1] with a maximum loss of just 0.8dB between 2-6kHz and should present minimal subjective impact. Pair matching was less impressive with these samples, however, a dip between 2-3kHz in one [red trace] resulting in a 2.2dB difference. Outside of this narrow band, the matching was within a tighter 1.5dB (200Hz-20kHz).

Distortion is fabulously low, especially through critical midrange frequencies at ~0.05% (re. 90dB SPL at 1m). Measuring the output of the substantial downward firing port was trickier, but not impossible, the 801 D4 tuned to 26Hz with a 19.5Hz-55Hz bandbass (–6dB) and with a mild tube/cabinet mode showing at 410Hz (–16dB). Its two woofers offer a near-identical output, operating between 31Hz-420Hz (–6dB) and combining with the port to yield a deeply impressive diffraction-corrected bass extension of 19Hz (–6dB re. 200Hz). There's payback for the combination of high sensitivity, low distortion and exceptional bass in the form of a fairly tough amplifier load, but the 3.4ohm minimum is still 'easier' than B&W's spec. 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


Aside from a slight mode at 1.3kHz (coincident with a peak in response), resonances are swiftly quelled

Sensitivity (SPL/1m/2.83V – 1kHz/Mean/IEC) 89.7dB / 89.5dB / 87.3dB
Impedance modulus: minimum & maximum (20Hz–20kHz) 3.37ohm @ 96Hz, 24.9ohm @ 41Hz
Impedance phase: minimum & maximum (20Hz–20kHz) –71° @ 48Hz, +43° @ 1.39kHz
Pair matching/Resp. error (200Hz–20kHz) 2.2dB/ ±3.3dB/±3.8dB
LF/HF extension (–6dB ref 200Hz/10kHz) 19Hz / 34.7kHz/33.5kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 0.25% / 0.05% / 0.25%
Dimensions (HWD) / Weight (each) 1221x451x600mm / 101kg
Price £30,000

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