I have spent time with Wilson’s Sophia III and with their Sasha W/P models. But I want to talk about their higher-end models, the Alexia and Alexandra XLF. These have the midrange drivers and tweeters in a separate box which is mounted above the bass bin inside a frame which allows them to be tilted through a quite surprising range of settings, the idea being, as I understand it, to allow for very precise time alignment depending on where the listener is located. As a rule, the bigger the speaker, the greater the physical separation between the drive units, and, therefore, the greater is the potential benefit to be had by getting the temporal alignment just so. At least, that’s the theory.
Tim spent some time observing Peter McGrath setting up a pair of Alexias. This involves positioning them in the room in the usual way, and then aligning the upper bins. The way the design works, as you might expect, this is very easy to do. The surprising thing was, however, the effect of getting the time alignment right. Wilsons are well known for, among other things, their holographic imaging properties. What Tim heard was how incredibly the image just seems to snap into place when you get the alignment right. It took Peter McGrath just 10 minutes to do the whole job, but there again he knows what he is doing! Interestingly enough, the image snapped into place not just for the lucky person in the sweet spot, but for quite a range of other listening positions too. Tim says they are comfortably the best speakers he has ever heard - and this from a guy who owns Stax SR-009's.
Recently, I spent some time refining the set-up of my own speakers. My B&W 802 Diamonds are not quite in the Wilson league for imaging, but they are still pretty good. However my listening room’s dimensions are unkind, and every now and then, having pondered long and hard over what problem I should be trying to solve, I try my hand at some room treatment work. Its a never ending process. In this case, I built a massive absorbing panel, about 6’ x 4’, and located it on the ceiling above the speakers, towards the back of the room. When you do stuff like this, it throws your previously optimized speaker set-up out of whack, and you have to start all over again.
I ended up moving my speakers a little more than 4 inches closer together, but that is typical of the sort of positioning accuracy you need to be bearing in mind. I had got the tonal balance where I wanted it, and the imaging was sort of correct. Instruments and performers were all where they should have been, but the ‘holographic’ element was missing - you could locate the position of instruments reasonably well, but somehow you could not just shut your eyes and visualize the performer. Trying to get this right, there are a couple of recordings I like to go to. These are inevitably recordings I played through the Wilson Sophia III’s and which, as I result, I had a good idea of what I ought to have been hearing imaging-wise. And I wasn’t hearing it.
I remembered what Tim said about the Alexias, and how Peter solved that problem by the simple expedient of tilting the mid/tweeter unit forward in its frame. My 802’s don’t have that adjustment. But then I thought why not just try tilting the whole kit & caboodle forward? I did. Nothing happened. So I tilted them a bit more. Still nada. By that time I had run out of adjustment range on the 802’s very beefy threaded spikes. So I found some wood to prop up the rear spikes and tilted them as far forward as I dared (802's are deceptively heavy). Well, that did the trick. All of a sudden the soundstage deepened and widened, and individual instruments began to occupy a more definable space. In particular, vocalists now appear tightly located, centre stage, just behind the plane of the speakers, and just in front of the drum kit. Kunzel's 1812 cannons are amazingly precisely located. Job done!
The rear spikes now sit in cups on a pair of Black Dahlia mounts, and everything is pretty solid. With the tilt, I found I needed to position them a couple of inches further back, but that’s fine - nobody can get behind them now (have you noticed how people always seem to be irresistibly drawn to the rears of large loudspeakers?) and accidentally topple them forwards. See the photograph below for an indication of the degree of tilt.
I’m not sure quite why this tilting has the effect it has. The design of the 802’s is such that the vertical and horizontal dispersion are probably very similar, outside of the crossover region at any rate. Perhaps I am reducing the energy reflected off the ceiling, but that is speculation, and well outside my sphere of competence. In any case tilting is surely a tool we can all add to our room-tuning arsenal. It will certainly be a big part of mine for some time to come. At least until I can afford Alexias …
