In Reply to: Alexia not time-coherent? posted by genungo on September 7, 2014 at 13:56:01:
Not time-coherent. I don't agree with your interpretation of JA's words. You have to think about group delay as well as phase. The order of the crossover affects both phase shift and group delay. That is why a 4th order LR crossover can be in phase but not really time coherent because the phase rotation delays the wave propagation. The Alexia even inverts polarity.
"This graph reveals that, as in the Alexandria XLF, the tweeter is connected in positive acoustic polarity, the midrange driver in negative polarity. However, with the tweeter module set up by Peter McGrath, the graph also shows that the negative-going decay of the tweeter's step smoothly blends with the negative-going start of the midrange unit's step, confirming the excellent frequency-domain integration of their outputs seen in fig.4. "
JA doesn't mention time coherence at all. He talks about frequency domain integration.
Check out square waves from the Thiel CS5
http://www.stereophile.com/content/thiel-cs5-loudspeaker-measurements-0
Not as good as the Quad 63 but not bad all the same.
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Follow Ups
- RE: Alexia not time-coherent? - morricab 04:47:32 09/09/14 (3)
- RE: Well, "...those arrivals will not be discerned as separate events."... - genungo 06:57:49 09/09/14 (2)
- "...those arrivals will not be discerned as separate events." ie Reviewer speak not Science Speak. - Edp 15:47:16 09/09/14 (1)
- RE: "...those arrivals will not be discerned as separate events." ie Reviewer speak not Science Speak. - genungo 16:13:51 09/09/14 (0)