Hi Bif, I've found that time alignment is certainly worthwhile, but let me just say that all you may need is a way to visualize how and why it would be important. I'm not technically as well versed on the subject as some, but I do have some direct user experience with it. I'm in the process of triamping my rig. Each amp I have (and will be adding) will have a suite of (digital) tools which include a pair of xovers, EQ and time delay. Each pair of tweeters, mids and woofers will have their own amp...and each of those frequency bands can be delayed the appropriate amount - dialing in by ear alone, at the lp, is sufficient. I can tell you that in practice that process is far from complicated and can be done in a couple minutes by anyone. It just may seem impossible to grasp for you at the moment because (understandably) you don't have any way to vary the control over your time alignment one way or the other so there is no way for you to realize its effects at this point. But, try to visualize it in terms of what you may already have some ordinary experience with. Try this: turn on a TV in one room of your home and then turn on another TV in a different room, but turn that one up loud enough to hear it while you're in the other room listening to the 1rst TV. Make sure they are both on the same channel. You can't help but notice the substantial time delay - like a rather serious echo, but in a nutshell, that's really all there is to time alignment. You've likely heard this effect countless times before without thinking about it at places like car dealerships, fire halls, etc...places where a PA system is using more than one loudspeaker in different places outside (usually on the other side of the building), creating the very noticeable amount of delay. Now, the big difference (apart from the sheer amount of time in the delay) is the fact that, like with the TV example, all of the frequencies overlap...hence the echo effect, naturally. But, with HiFi speakers (except to a degree at the xover regions, which we'll ignore here) the frequency groups are largely separated in their delay. What this means is that (with any conventional, flat baffle arrangement, anyway) the highs reach your ears first, then the mids and then the bass. Basically it means that the highs are simply being projected out into the room and are imaged a little closer to you (in soundstage distance) than the mids, which are in turn projected a little farther into the room than the bass...it simply becomes apparent to you that the higher frequency band seems physically imaged a little closer to you. Time alignment resets this effect, moving the imaging of the higher band back into place with the frequency band below and gets all the instruments and voices that much more correctly positioned from top to bottom in the frequency range...a very nice and more realistic or natural presentation - definitely worthwhile. Once you've ever heard the effect for yourself it takes all of about 5 seconds to solve the mystery as to how and why it might be useful, but, with speakers if you visualize the difference in terms of the distance of the soundstage image from you with each driver's operating range, then you just may at some point be able to recognize just how most speakers have somewhat less than ideal time alignment. And some will seem a little worse or better than others. If you use subs, however, it is always recommendable to take time alignment into consideration along with the other factors concerning placement, but I don't believe perfect time and phase alignment has ever been done in any speaker and I may never see it in my lifetime. But, triamping in this way for me is giving me the opportunity to pretty much 'fix' the time-alignment problem, which won't hurt me at all. Apart from building your own speakers though, it seems there are not too many designs that have actually tackled the problem, as near as I can tell. Until more makers become convinced there is a market for time-aligned cabinets (expensive because it's so labor intensive), then there may be only a handful of alternatives for us. Other problems for manufacturers include that in designing cabinets for true time alignment (meaning driver offset at something close to the correct distance) they start getting into a world of cabinet diffractions and reflections - not easy enough to successfully solve, particularly in any aesthetic sense. It's not horribly critical to get the distance precisely right, but the closer the better up to a point...like trying to position both your speakers the same - it might be quite good to get them within, say, a 1/4" of each other, but under an eighth of an inch??..at some point there ceases to be an improvement, but then again, with time alignment you would notice generally a better sense of scale and improvements in the macro areas of the soundstage...while the soundstage details would remain largely unchanged. Hope this helps.
