Are we refering to the narrowed vertical nulls and less than ideal directivity at crossover or is there more to the story?
Yes, their limited ability to play well up to 1.5 kHz, and articulate the octave immediately below there. :scratch2:
Considering switching out 123A-1s for those Eminence.
There are less expensive ones, the 3012HO with higher sensitivity, and the 2512, intermediate between them, but we're not going to get extended bass out of those in rational alignments. I'm already getting leaned on to build a bump filter for 3012LF.
Get Pete Schumacher to make DC300 happen.
He took a couple of shots at that in round one of that thread. He understands the requirements better now, tho, so maybe.
Posting round two was a long shot; I was hoping that a bunch of the resident Tech Talk PCDers would take up the challenge, but could see the minimal level of interest from the number of downloads of the files; it didn't happen 'til Pete took up the challenge. EconoWave is foreign territory over there; perhaps that will change.
Question, does "relative offset" as discussed in the PE thread, imply offset of drivers measured from a fixed designed-acoustic-center? Or what?
I don't know, and you see me stumbling with that in the thread. Maybe if you post that question over there those who understand it better will clarify.
Minimum phase is the measured phase less that contributed by the flight time. I thought, so long as I did not adjust the start time of the measurement window, from any given measurement point, the differential between them would remain, as I can see that in the individual impulse responses: the woofer is earlier. If I measure them at their individual axes from the same distance, that will give me their absolute offsets, in the impulse, but in calculating minimum phase, it seems CLIO does not use the start of the window as reference, rather, the impulse itself. I'm obviously unclear on the concept.
PCD apparently assumes no offsets in the acoustic phase, and many users are generating minimum phase from the frequency response itself using a different program, stripping the measured phase (if they even have that) from the FRD and patching in the separately calculated minimum phase. The physical offsets are then estimated and entered into PCD.
I offered up the suggestion of the method of Ralph there to get around the estimation of offsets, which, as we know, is inaccurate. The option of iterating offsets to the measured response of the two drivers combined from the same measurement point is only available to those having the facility to actually measure that, whereas many are merely working from published response curves by manufacturers and other designers such as Zaph, using a third program, a graphic response tracer, to generate the requisite FRD file. The Ralph method worked for both Pete and I, but I somehow got the phase inverted, apparently.... :tongue:
