Under our room conditions the bottom end worked very well with both ports unobstructed and the speakers sited well clear of walls. Sensitivity is a quite generous 90dB, especially since the bass is well extended (-6dB @ 22hz in-room) and the easy-to-drive impedance stays above 6ohms through most of the band (dipping marginally below this above 10khz).

Pair matching is satisfactory enough, albeit with minor variations at low frequencies and the impedance also shows a minor 'glitch' at 950hz. The front port is tuned to 37hz (28hz with foam lining), while the rear port is tuned to 68hz (50hz when lined).

Lack of energy

As predicted by the in-room responses, the 684 delivers an impressively neutral and even-handed sound that's thoroughly competent in nearly every respect, even though it does reflect its modest price
and aspirations to some extent.

Interestingly, the mild lack of presence energy that seems to be a regular feature of most Bowers & Wilkins designs is virtually absent on this occasion and in this respect the 684 has an attractive openness that is not shared by many of its stablemates.

Rather less happy is the top end, which sounds a little too obvious and slightly congested, especially as it doesn't have the sweetest character through this part of the band. Whether that mild hardness at the top end is related to the upper treble peak which showed up on the room measurements is hard to say; it's also curious to note that the same peak was much less obvious in the 683 model, which shares the same tweeter.

Budget limitations

That combination of an open presence and slightly coarse top end means that the 684 sounds happiest when operating at modest levels, which suits its fundamentally open neutrality particularly well.

Start winding up the volume and although the speaker hangs together very well, delivering a powerful bottom end foundation, the mid and top moves progressively out of its comfort zone and starts to sound harder and more edgy, betraying the inevitably compromised ingredients of a budget speaker.

The dynamic performance – specifically the limitations thereof – is the other factor that constrains the performance of this speaker. While dynamic range per se is satisfactory enough, there is clear room for improvement – subtle low-level detail, such as the fine texture of orchestral instruments, tend to be masked.

Fair price

Stereo images focus well laterally, but depth perspectives are somewhat limited and ambient information isn't very well resolved. Furthermore there's also a clear lack of overall dynamic tension. Again this is quite normal for a speaker of this type, but remains a limitation nonetheless.

The above criticisms should not be taken as harsh. When its reasonable price is taken into account, the B&W 684 is actually a very good loudspeaker delivering a fine all round performance with an unusually smooth and neutral overall tonal balance.