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View Full Version : Boston Acoustics Pro50 active xover



sramnbear
02-21-2012, 04:28 PM
Has anyone had any luck running the tweeters active from BA pro50's? I am wondering what frequence range they operate in since the manufacturer doesn't disclose this info

Why So Cereal?
02-21-2012, 05:55 PM
They have an FS of about 1400hz iirc. So, rule of thumb says generally double the FS, and thats how low they can be crossed using a 12db slope (2800 Hz). Possibly lower with a steeper slope.

IIRC, the stock xover point is right around 3100 Hz.

sramnbear
02-21-2012, 08:44 PM
So any xover higher then 2800hz will work? Such as my CDT ex-560i crossover at 3700hz? I've been trying to search for these secret BA freq ranges all day! Lol

I'm looking to move these tweeters up front from the rear and add them parallel to my soft CDT tweeters (drt-25) so my rear fill wont drown out the front stage. Will this work?

Why So Cereal?
02-21-2012, 08:52 PM
If u parallel these to the other tweets, you'll change the impedance the xover sees thus changing the xover frequency. So, no.

Just use your HU to fade more up front or turn gain down on rears

sramnbear
02-21-2012, 09:12 PM
Even if it is a fourth/fifth order xover? I thought that this type of xover was meant to match the impendances. By the way I'm new to this so feel free to talk elementary to me sort of speak. I have more budget then knowledge

This particular xover has an extra output for image tweeters alongside of the main tweeters attenuated by 3db

Why So Cereal?
02-21-2012, 09:21 PM
Changing the ohm load will still change the point independent of slope as far as I know, but I don't know much about CDT gear.

At any rate, adding extra tweeters up front especially completely diff tweeters will causes issues with phasing and what not and could actually cause more problems than you'd be attempting to fix. The only reason I know of extra tweets is imaging tweets to raise the stage but that's not your issue and it's not always successful anyway.

I say either fade front, remove the rear tweeters, aim the rear tweeters to the back, or take the rears out completely.

sramnbear
02-21-2012, 09:59 PM
Thanks

keep_hope_alive
02-21-2012, 10:04 PM
Agreed. The crossover point is determined by the impedance load regardless of the order. Don't parallel speakers on a passive crossover unless you end up with the same impedance, and be aware of the impedance spike at Fs and its effect on the crossover point.

sramnbear
02-22-2012, 09:49 AM
I wish there was some way i knew how to calculate what this new xover freq would be. I just thought that since there were three outputs on the xover (woofer, tweeter, and image) that it was designed to have all three hooked up without changing the freq ranges.

When I said wired in parallel i just meant that's how the internals of the tweeters are hardwired inside the xover.