I am so confused! Are you now implying that using the E'Wave crossover at higher than 1.6 KHz is good?
No. I am just investigating the the effect of driver offset using DE250 on QSC446 in the stock PE KD trapezoidal cab with its fixed centers. JBL123A-1 is a shallow-frame woofer, and rear mounting it, the forward lobe is apparently tilted upward, with the lower null just below the woofer axis. I'm hoping the DC300-8 is enough deeper to significantly "normalize" the tilt.
I have not done anything to optimize the crossover other than increase the HF comp enough to render the system listenable, and I must say it is very much that, even with this too-high acoustic crossover frequency. At this point, I have confirmed:
1) My earlier finding that the standard eWave HF comp and crossover frequency need tweaking when using DE250/QSC446.
2) Your finding that with these center distances, there is a substantially usable forward lobe, assuming I'm not already above the upper null.
My intent here is to hold all variables constant other than the horizontal offset of the woofer in the interest of documenting issues inherent in incorporating this driver/waveguide combination into a "Deluxe" eWave design, and as you have already determined, it is worthy of pursuit. I'll move on to the other elements once this one is better understood and more clearly defined.
2 things:
-This confirms that with standard EWave core filter, horizontal offset between drivers (123A and DE250/QSC) is required without delaying circuitry in the x-o. Agree?
-This woofer may benefit from a Zobel?
Or does the bump near x-o suggest underdamping in the filter(s)?
The bump is coming from the 123A-1 woofer in combination with the stock eWave lowpass, and could likely be "fixed" in the course of optimizing the crossover frequency, (same as previously found with LE14A,) and as Jack found, I don't believe delay is requred to mitigate it. I am reminded of Gordon's earlier suggestion in this respect. From everyone's previous work with DE250/QSC446, I believe it's clear the highpass needs to be lowered to move combination with any woofer down to the target 1.6 kHz. Jack has provided guidelines for successfully accomplishing that, but it's "One thing at a time" right now.
As Wayne has suggested, there may be other stuff going on here of which we are as yet unaware; I'm on the lookout for that in the course of performing these measurements. Thus far, again confirming Jack's findings, I don't believe the horizontal offset (the compression driver being physically so far behind the woofer) is so much of a problem as earlier presumed. I'll know more once I get everything aligned closer to were it likely should be and measure the actual offset of the acoustic centers.... :yes:
