Line_array xover

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It is hard to say what would work best until you get it assembled and do some frequency response and impedance tests on the system as a whole.

Have you considered an active crossover for it?

This would allow you to experiment very easily and then once you find the parameters that work best for you then you could design a passive crossover for the system if you wish to do so.

With that many drivers you should be able to drive it with two decent sized power amps.
DIY amps maybe?

:cheers:

jer :)
 
Thanks !

That looks like a standard crossover design.

They used the 12db Linkwitz-Riley cuve.

here are a couple of calculators that may help you.
I plugged in the value's and they came up with very similar results,

2-Way Crossover Designer / Calculator

Crossover Design Calculators


jer :)


Thank Jer.

If i drive my line -array with bi-amp (with my Sunfire 5x425)

I think to go with the Behringer Ultradrive Pro DCX2496,

Include EQ and X-over activ

Behringer: ULTRA-DRIVE PRO DCX2496


What do you think ??
 
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Well worth a read if you do not know of Jims write up
http://audioroundtable.com/misc/nflawp.pdf

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Personally use as steep as slope as possible.I use a 3rd and 3rd or 3rd and 4th order crossover.
Measurements.. knowing what you are starting with is the only way to get a line array to work.Other than that it is a short in the dark.
If you do not know get a OMINI mic from PE a cheap measurement system this will help you like no one else can.This will show ya what you are doing how they measure ect.Moving the mic up or down 2-3" can put the measurements all over the place.So selection of listening distance and height all come into the crossover design selection.

Just a few ya get the idea :)
 
Thank RAW for your comment.
Very great Line -Array.

Like you can see on my picture, it's a some-year-project. I've built only 4 pt2c-8. I just bought 10 others pt2c-8 for a total of 9 on each side so I don't have choice to rebuilt my Xover. I'll carefully read the document that you sent me about Jim...I didn't expected that so complete for my line array. I work on that
thank you
 

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Spicer,

With a line array because of the reduced excursion per driver for a given SPL compared to a single driver of the same type, and even compared to a different and bigger driver the line array typically has less THD and IM for a given SPL.

This is one of the big advantages, other aspects like the comb filtering are compromises that some don't like. Personally I find that particular compromise not objectionable generally speaking (fwiw).

So, as far as signal path and any electronics in the system, they are more likely to be clearly audible. Put another way, they may be a limiting factor for the sound quality. I'd be cautious about using a stock Behringer EQ/xover box for that reason. They are inexpensive, so it might make sense to "dial it in" with the easy to adjust electronic box, and then implement an exact or a variation thereof in passive.

Also, you have to be aware of the total *acoustic* crossover, not just the electrical slope. What counts is the *acoustic* slopes and frequency response.

In general after testing and using all sorts of xovers, I generally avoid the 2nd order and 3rd order filters. Prefering the 1st order (which for most drivers is not going to be good) and the 4th order variants... it seems like all xovers are inevitably a balancing act and none ever really are *dead bang* what you want.

The other issue to consider is acoustic center. The acoustic center of the woofers is going to be father back into the box than the planar tweeters. The relationship between that source (the HF end of the woofers) and the tweeters in time will be rather different as you move from on axis to off axis. This being more different if the tweeters are "inside" or "outside".

If the tweeters are outside, and the cabinets are more or less forward firing, not toed in, as you move from on axis and in front of the speaker to the center listening position, then the direct path between the tweeter and the woofer starts to look closer. Conversely, with the tweeter inside, the opposite occurs and the distance looks larger.

This will effect the freq response at the xover region.

One advantage, amongst the disadvantages, of a DSP based xover solution is the possibility of delaying the tweeters so the acoustic centers align - at least for one listening position.

The only other viable solution is a mechanical/physical offset built into the cabinet.

Among the many compromises this is another. There are no perfect solutions for this problem with this sort of speaker system.

Otoh, this is getting pretty fine and detailed.
 
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