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    • What you're describing is the limitations of how phase/group delay is measured.  If you look closely at your spectrogram posted above...     In the 1-6 kHz region, you actually see two different times that there is high SPL: one at close to 0 ms and another as much as 0.8-0.9 ms behind the first event (depending on frequency, shown in the vertical direction).  If you slightly change anything about how the measurement is done in that frequency band, you will see dotted line move due to this dual-impulse event.  The way REW measures phase and takes the derivative of the phase vs. frequency curve to obtain the group delay vs. frequency is highly sensitive to this dual impulse nature of this particular driver/horn.    Most drivers/horns don't have a secondary pulse that's anywhere near the SPL as the first impulse, so REW's calculation of phase/group delay will produce the same results regardless of small changes in lobing or microphone position, and you will see a consistent phase/group delay response from measurement to measurement.  The driver response shown above is ambiguous in terms of phase and group delay because there are actually two events occurring, the second of which is almost as loud as the first, and in fact does overtake the initial pulse of SPL depending on microphone placement, showing the three dimensional polar lobing issue of the driver/horn combination.   Also note that REW calculates phase in a left-to-right, bottom to top fashion as shown in the spectrogram plot.  If there is any disruption or upset in the calculation of phase vs. frequency, REW will simply add  360 degrees of phase lead in order to "back up" to a phase lag as the frequency increases during a measurement calculation issue, and you see that a lot in the REW measurements of phase.  The phase seems to jump forward by 360 degrees as the frequency increases when you have an issue with a measurement.  This is why I recommend using a lot of absorption in and around the driver/horn areas--to reduce nearfield early reflections as much as possible.  This results in much better phase vs. frequency curves and group delay vs. frequency curves (an inherently noisy calculation at any time).    So to answer your question: which is correct phase?  None of them, because the notion of a single phase curve is not possible when you have two impulses occurring, as your spectrogram shows.  And small changes in anything during the measurement will cause the phase/group delay calculations to move around, sometimes dramatically.   The reason why I recommend looking at the spectrogram is because it doesn't really change much, even though the phase and group delay calculations might be moving around a lot.  The spectrogram plot will tell you what the issue is: in this case, that you've actually got two phase events, and REW can't always decide which one is the correct one vs. frequency.   Chris
    • Vented tweeter, no base plate, smaller cabinet, some cosmetic differences here and there. Thats basically it i think. 
    • Looks like the best advice I've seen on any topic in a while.   I'd say "use the measurements to get a handle on what you're hearing instead of making what you're hearing being the result of measurements" if that makes any sense.
    • I have 2 used PSD2002 8 ohm diaphragms Free both read 6.1 
    • Seems like a decent deal. What is up with the tweeter? Seems like the horn is facing backward.   https://chicago.craigslist.org/wcl/ele/d/electro-voice-v-four-speakers/7032562133.html
    • Kinda like Detroit....it's a great place to be FROM.
    • They appear to do good quality restorations, from what I see in their pictures. I hope they rescue, restore and sell lots of Klipsch speakers. Some folks might think they are taking away from new product sales, but I think they are generating free publicity for Klipsch.
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