Do you really believe that your amp/processor/HU/passive crossover is actually giving you out-of-phase outputs for mids and tweeters? Like you just stumbled onto something that the engineers overlooked?
indeed, that was a great read. however, I still feel a little unsure about whether passive and active crossovers (including amplifiers with a -12db LR2 crossover) include an inherent phase modifier in the design. In addition to that, if you have a passive component set HPF'd on the amp and also a seperate passive crossover (for example a 60hz passive is crossed 100hz on the amp or hu) would this end up adding twice the delay?
What you're talking about is cascading filters, and yes there is a phase shift twice if there are two filters on the same channel. What I take away from that DIYMA thread is crossovers should be used as protective filters to cut power as well as restricting drivers to operate in their optimal acoustical bandwidth. Flat phase is the goal, and -24 dB LR filters makes that easier. That filter is super common with DSPs, but most of us don't have that, so that's why you might need to swap polarity of one driver to address a null. If you measure a null and EQ boosting doesn't bring the null up you are probably measuring cancellation.
Ok, ok. I think i was confused. The 80prs gives you phase adjustment for each crossover point. I was thinking the "phase" option was effecting the whole freq band the driver is was playing. It only affects the point of x-over and slope. a -12 db slope will give you a 180 degree phase. In order to correct that so its in phase with the driver its sharing frequencies with, i need to flip the phase of that x-over. assuming the other driver had a -24 slope(almost no phase change), Now if the other driver had a -12db slope as well, id still need to flip that drivers phase as well. This is all complicated to explain in words. pics make it so much bettter. Anyway, i think i understand it.
Don't know if you still need help with this, but I've been having crossover issues and was doing a lot of research and learned a lot. a -12db lpf will shift the phase -90 degrees and the -12db hpf will shift it +90, for a phase difference between the 2 of 180. Each order changes it by 45 degrees PER FILTER but people usually say 90 degrees per order because the lf shifts - and the hp shifts + 45 / order
Had this same problem. I talked to a lot of Hertz dealers and they said with 2nd order crossovers, the manufacturer absolutely takes care of the phase issue, at the crossover. So you wire + to + and - to -... I don't know how it is with other manufacturers, but the ONLY way to tell for sure is by using a phase checker or whatever the thing is called. A good reputable shop will have one. And as for the delay issue, from what I understand, each time the signal passes through a crossover, the phase will be modified, but that isn't "delay" per se. If it passes through 6 separate 2nd order hpf crossovers for instance, each time will add +90 degrees of phase (-90 for lpf), so 540 degrees, but since it's phase and not delay, that's the same thing as a total change of 180 degrees. Every time you get to 360 you start over at 0
