MEASURED PERFORMANCE
Our frequency response analysis clearly shows the B&W 804D has the usual phase dip at crossover due to the use of a slow (first order) low pass filter feeding the midrange unit. B&W insist this gives a better sound irrespective of the dip. In practice the dip shown tends to change according to microphone position but its existence is consistent all the same.
    Tweeter output was also consistently high, peaking up by +6dB around 12kHz. This will produce audible brightness in the treble, even a treble sting. High frequency output above 3kHz was generally strong from the 804D, giving good detailing but a bright sound balance. High frequency output from the 804D borders on excessive for a so called high fidelity loudspeaker. It is far from accurate.
    The midrange unit peaks around 600Hz in the midband and will push vocals forward a bit, giving them good presence.
    A third octave pink noise analysis, not shown, shows bass output is very even down to 55Hz (foam port bungs out). Port output peaks around 30Hz and its effect can also be seen in the impedance curve as the usual dip at this frequency. Bass will be quite dry but there is sufficient subsonic output to give some low bass weight.
    Sensitivity was high at 89dB from one nominal Watt of input (2.8V) and overall impedance measured 6 Ohms. The 804D uses a 4 Ohm bass unit measures 4 Ohms across the lower midband, from 90Hz up to 700Hz, so it will draw current.
    The 804D will have even sounding bass with a dry-ish quality and some subsonic content. It will also sound bright across the midband and sharp in its treble, straying far from accuracy. It is normal as a load, good sensitivity meaning 40 Watts will make it go loud. NK

FREQUENCY RESPONSE

IMPEDANCE