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Horn-Loaded Speakers
Topic: CD horn and JBL: Crossover point

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Posted by Dominic on 09-26-2006
Hey Rom etal.

I'm entering into unknown and difficult to intuit territory for me.

I aquired a pair of very large constant dirrectivity horns EV hr9040 a, a little while ago and i now have a pair of jbl 2420's to power em.

I haven't put them to gether, nor listened to the horns before. I don't know what to expect and this is the first project where i'll actually need to make a filter i think. So the horn is designed to pass 350-16000, and the factory recomended xo for the driver is 800 with a response up to 20k. I don't want to make anyone do my work for me but a friendly hand on how to proceed would be much appreciated.

All of my experiments have been in single driver setups necessarily with cones and short horns.


maybe i'll just start with a high pass around 800hz?

Posted by Romy the Cat on 09-26-2006

Dominic,

I have no idea. I never used them and hardly used anything similar.

Generally there is no abstract intellectual value in the targeting any specific crossover point. People out there suggest “do not cross here” or “do not cross there” but it is all BS. A channel, accompanied with it ambianic room modes, accompanied with neighboring channels, accompanied with own limitation of own performance and accompanied with the intentions that you put into this given channel will naturally recommend you where it should be crossed. Listen what that horn/driver does at the boundaries of it’s own range and listen if you neighboring channels do it better.  A generator, RTA and phase tester are usually necessary as well.

The caT

Posted by loach71 on 02-18-2008
Dominic:

Welcome to the army of the "Great White Horn". I have been using these beasts for almost thrity years.
The flange on these horns is designed for use with a 1.4" or 1.5" driver. The JBL 2420 is a 1" 3 bolt "JBL pattern" driver.
Adapters are available from Electro-Voice (ADH-1) that allow a 1" "thread on" driver to be used with these horns. The driver to use with these adapters would be the JBL 2425 or JBL 2426 with the 1" "thread on" connector.

I am an active crossover type of person -- I like 24 dB / octave slopes. That being said, on the bottom end anything between 700Hz to 1 KHz works well with these horns and the drivers I listed. The actual crossover point will be predicated by the upper response limit of you woofer and its enclosure. On the high end, I've always used a crossover point of 10 KHz to a JBL 2404 "baby cheek" tweeter.

Hope this helps.

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