Time and Phase Coherent Speakers

[YBArcam]

I wanted to get people's thoughts on time and phase coherent loudspeakers. I'm enjoying my Tannoy Revolution DC6 immensely, and with the dual concentric driver they are, at least in theory, time aligned. I can't help but think this design is responsible to a large degree for how the speaker sounds.

I found a nice explanation that is relatively easy to understand on Thiel's website (link posted below). Of course, they are probably one of the more famous time and phase coherent speaker makers. It's a concept that just seems to make a lot of sense, at least on the surface. It's a little strange to me that there aren't many companies that share this vision. While phase coherent speakers may not be easy to implement, time coherence seems the opposite. All you need to do is utilize an offset tweeter, if I'm not mistaken. A few others employ this design technique, but it's still the minority.

http://www.thielaudio.com/THIEL_Site05/Pages/FAQs/faqtimephase.html

[Dual-500]

I joined the ranks of time/phase aligned systems about a year ago by changing out analog crossovers to digital crossovers in my system on both L&R mains and center.

The first thing noticeable was that it was easier to tune it using 1/3 octave spectrum analyzer. Next, after tuning with test gear, I generally tweaked things a little by ear to find the most pleasing settings. With time corrections in place using the digital crossovers (DSC's), now I tune it up with the RTA and that's it - it's done - and sounds great. It also takes less adjustment from both gain balancing and equalization correction.

I know using electronic correction is a bit of a departure from your OP - but, the results are much the same. Baffle orientation to put drivers on perpendicular plane to listening position can also be accomplished with focus or positioning of the enclosures and it particularly easy when the system is flying.

I've used horn loaded systems years ago that were analog and phase coherent. They sounded great.

[JoeE SP9]

Full range electrostatics are time aligned and phase coherent. One diaphragm and no crossover assures it. Time and phase alignment are a very good thing. Getting rid of passive crossovers is icing on the cake.

Even if time/phase alignment is not possible or feasible active electronic crossovers are almost always a step up from passive crossovers.