When you’re unpacking a pair of stereo loudspeakers and find, between the ubiquitous plastic bag and the surface of the loudspeaker itself another bag of soft synthetic material, you know that the speaker has something special in the way of its finish. And so it was with the JBL LS40 loudspeaker pair. It wasn’t the black end caps, but the piano finish side panels, glossy, darkly grained and perfect.
The front is covered by a removable cloth and plastic grate grille, which hides the very unusual driver complement. Technically this is a three-way speaker system – despite it being by far the smallest of this bunch (‘bookshelf’ sized, but still quite heavy). That is, the audio signal is divided into three distinct frequency bands. What’s unusual is where those bands are. The woofer actually goes all the way up to 2600 hertz. Then a horn-loaded compression driver takes over and carries the signal up to 7000 hertz, whereupon a ‘ring radiator’ tweeter takes over. This last looks like a curved probe rather than the usual dome.
The 2.6-7kHz compression driver is in a deep, widely spread horn. Generally when you see a horn on high fidelity loudspeakers you think ‘high efficiency’, but that wasn’t the case here. JBL rates them at a slightly-below-average 87dB for sensitivity.
Happily, they sound as good as they look.
The concentration on the two high frequency drivers gave these speakers a forward, strong and crisp sound, that still preserved excellent balance. There was no particular emphasis, and the bass extended down quite well to encompass the major thrusting of air from kick drum. Indeed, I would have guessed a little more bass extension than suggested by the specifications.
Despite the lowish sensitivity, these loudspeakers went loud and maintained their aplomb in doing so, so long as you have the power available to make them do so.