I was following with interest the thread a couple weeks ago about how Thiel's moving from sealed to radiator/ported woofers threw off the low-frequency phase coherency by 360 degrees. How does this make for a "coherent phase" loudspeaker if so much of the frequency range isn't aligned at all?
Stereopile always makes frequency response measurements of port vs woofer. My 2.4 shows that above 100Hz, the radiator's output is 15-20dB below the woofer. So if I'm playing music with no bass content below 100Hz, do I have a reasonably coherent phase speaker?
And as all Thiels were no longer sealed after the late-90s, why do their spec sheets state "Phase Response: +-10 degrees"?? (or 5 deg with 2.3 & 2.4) Given Thiel's comprehensive tech data, why is this so vague? As it states no frequency, is it unspoken that this is only valid above the woofer's passband? The clean-decay step response plots suggest at least the 'time' coherency to be true.
My 2.4 brochure states "Completely Time and Phase Coherent." Then it states the 'time' portion is from the slanted baffle and the 'phase' portion is the first-order slopes *between the drivers* -- is this to suggest that what happens outside the XO, ie the bass loading, is 'outside' a driver rather than 'between' drivers?? And therefore low frequencies are inapplicable to the "complete" phase coherence and +-5* spec? That seems very un-Thiel-like, and I'm sure someone long before me would ask that question!
I'm sure someone on this thread has the necessary acoustics (or marketing-speak) background to offer insight here. All my pre-Thiel speakers were sealed so I'm finding this, uh, interesting...