B&W Nautilus 805 loudspeaker Measurements part 2

Fig.4 shows the B&W's overall response, averaged across a 30-degree lateral window on the tweeter axis, spliced to the complex sum (amplitude and phase) of the nearfield woofer and port outputs. The shape of the curve is astonishingly similar to that of the $8000/pair B&W Silver Signature I reviewed back in June 1994: a flat midrange and treble, with a slight boost in the upper bass. Although this will be mainly due to the nearfield measurement technique, it will satisfyingly add to the illusion of the speaker being larger than it really is. The useful bass output extends down to around the port tuning frequency of 40Hz, with the actual -6dB point lying at 34Hz.

Fig.4 B&W Nautilus 805, anechoic response on tweeter axis at 50", averaged across 30 degrees horizontal window and corrected for microphone response, with the complex sum of the nearfield woofer and port responses plotted below 300Hz.

The lateral dispersion (fig.5) is superbly well controlled, with only a slight amount of beaming apparent at the top of the woofer's passband. No wonder LG was so impressed with this speaker's imaging specificity! LG did find the balance to change significantly when he stood up, however, and fig.6 reveals that significant suckouts develop in the crossover region more than 5 degrees above or below the tweeter axis. Use of appropriate stands is mandatory with this speaker.

Fig.5 B&W Nautilus 805, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 90 degrees-5 degrees off-axis, reference response, differences in response 5 degrees-90 degrees off-axis.

Fig.6 B&W Nautilus 805, vertical response family at 50", from back to front: differences in response 45 degrees-5 degrees above HF axis, reference response, differences in response 5 degrees-45 degrees below HF axis.

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