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Get familiar with the reaction system: Introducing the Reaction System
Comments
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12/18 elec yields 4th acoustic, and should typically be IN PHASE or same polarity.
There are however companies that wire drivers backwards to the terminals like JBL does. If you measure the impulse response and the peak goes down with positive to red wiring, then the polarity colors are reversed.
InDIYana Event Website
Thanks. That is what I’m seeing in actual measurements- positive / additive to the higher end of the Xover point (vs a bit of destructive interference when inverted), but a bit of negative on the low side of the Xover point.
...Or maybe just best not to mix odd with even filters due to phase being 90 degrees off? Can deal with 180 (flop + with -), but 90 and 270 problematic.
I'm going to look at comparing the 2nd order LP / 3rd order HP with both; a 2nd order LP / 4th order HP, and a 3rd order LP / 3rd order HP, measure and look at the level of squigglies (technical term-ha), i.e. phase issues constructive and deconstructive interference around the Xover range.
Usually the 90deg off is required due to driver Z offset.
InDIYana Event Website
I tried a few different Xover formats, keeping with the current 2nd LP/3rd HP component values, just adding an additional inductor (of differing small values) where appropriate to change the format / orders.
Comparing to the initial 2nd order LP / 3rd order HP (non-inverted), I set up a 3rd order LP with the 3rd order HP, as well as the 2nd order LP with a 4th order HP. As such, trying to minimize the shifts (although the roll offs of course changed a bit) with the idea of just focusing on the affects on the (squiggles) interactions due to phase differences of the Xover formats. In the end, their was little difference (at least from measuring from a distance- near the listening area) in the outputs. While the squiggles moved around a bit (up / down frequency) their range was little changed. The biggest shifts were in looking at results with vs without inverting one driver.
Sticking with the current 2nd/3rd format, and moving to a less critical 'smoothing'
I have also been in the crossover twerking stage and I am trying a new strategy of giving priority to above axis response. My project has a sloped baffle but it is a short floor stander. I am currently listening to what I consider the best so far, a third order electrical on the tweeter and a second order on the woofer. I do not recall the tweeter polarity because I use a toggle switch, but one is much better above tweeter axis so that's what I' m definitely leaning towards.
When you tweek while working, its called twerking.
Interestingly, my smaller 3ways will be sitting on very short stands with a ~ 5 degree tilt (just under 31 in. ht), so similar positioning. My last umpteen projects have been woofer(s) with mid/tw coaxials (or just woofer with broad rangers) so maybe seeing and comparing measurements of separated mid and tweeter to my previous builds is what was giving me a go-around.
It is very common to have a 2nd order electrical on the woofer/mid and 3rd order on the tweeter, when targeting 4th order LR anyways.