Loudspeakers

B&W's most compact D4 model shares its 25mm Diamond Dome tweeter, set within the tapered and recently elongated 'solid body on top', with the flagship 801 D4 [HFN Nov '21]. This rigid and lightweight dome has a very extended HF response, reaching out to 61kHz (–6dB re. 10kHz), with well-managed breakup modes at 46kHz and 70kHz [pink shaded area, Graph 1 and Waterfall, Graph 2]. Measured on this tweeter's axis, the 805 D4 shows a 'brightened' treble that lifts some +6dB above the mean midband level at 10kHz, the dished response causing sensitivity to fall short of B&W's rated 88dB. In practice, 86.2dB (500Hz-8kHz) is more realistic while the 1kHz spot figure is lower still at 83.8dB. Response uniformity is below average at ±4.4dB but the L/R pair matching is superb at 0.75dB (200Hz-20kHz).

The 165mm Continuum bass/mid driver operates over an 82-400Hz bandwidth (–6dB, re. 145Hz) with nearfield analysis revealing a more erratic output >800Hz and a broad peak at 1.3kHz, also visible as a mode on the CSD plot [Graph 2], the forward response [Graph 1] and via the port. The latter is tuned to 41Hz, offering a broad 26Hz-97Hz output that brings the 805 D4's corrected LF extension down to a very respectable 39Hz (–6dB re. 200Hz). Again, what may be cabinet standing waves are seen at 330Hz (–11dB), 700Hz (–14dB) and 1.3kHz (–19dB). The largest swings in impedance and ±57° phase also occur through the bass, the toughest – though not especially 'tough' – being at 145Hz (5.1ohm/–26o) just before the 4.65ohm/187Hz minimum. So what the 805 D4 lacks in sensitivity it recovers in good bass extension and ease-of-drive. PM