Line Array question (concerning Horns and CTC)

[Hybrid fourdoor]

I have two questions.

I want to use the W3-871's (tang bands), but it seems in order to avoid any comb effects I would have crossover at about 4K Hz. So my question is would it be best to crossover to a horn tweeter that way I can use only, since many have SPL's of around 97dB+. Otherwise it seems I would have to use alot of tweeters to match the output of the multiple woofers, and using one dome tweeter would be a waste, since I would have to bring the woofers SPL down to match the tweeter. I never experienced horns before, so I am not familar with how they work, other than they are usually very sensitive, plus something about directivity

Also when poeple mention center to center. Would this apply to situations where you have like a MMTMM? Should you still theoretically preserve the CTC rule when you go across the tweeter...like if you have 4 3" woofers in a line and place a tweeter in between, you still want less than 3" between the inside woofers where the tweeter sits.


-David

[Hybrid fourdoor]

Maybe something like this tweeter

Peerless 811647 1" Horn Dome Tweeter



Has a sensitivity of 99dB and is only 3 7/8" in diameter

Or are the horns with the big wide mouths better? Like the JBL type?

[Jim Griffin]

For MMTMMs, MMMTMMMs, or whatever vertical arrayed line of drivers, you would still use the same guideline of spacing which is to space the mid/woofers drivers center-to-center no more than one wavelength c-t-c at their highest frequency of operation (crossover point). This assures that you would achieve a near coherent source of sound from these drivers.

Then space the tweeter and the inside mid/woofs also at less than one wavelength apart at the crossover point. This prevents comb lines from distorting the vertical axis phase front except at relatively large angles (typically more than 30 to 45 degrees off the vertical axis). It also helps to more seamlessly blend the sound from the M's and the T as you go through the crossover.