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OzMikeH 14th August 2007 07:28 AM

Modifying Behringer CX3400 crossover
Has anyone delved into these?
I was about to buy one then I discovered the crossover freq cannot be set to more than 9.3kHz.

I wanted something about 13 or 14 kHz.

The low end will be ok, I want that at about 150Hz.

Are there circuits about for these?

Cloth Ears 14th August 2007 07:41 AM

Interesting. Mike, what do you need a 24dB/oct crossover at 13kHz for, the tweeter or to roll off a full range driver? And, what drivers are you using this for?
The difference is less than half an octave...
And it won't be the be all/end all in crossover transparency...

P.S. I've got 2 and a CX2310, so I'm a convert - but there may be a better way...
P.P.S. If you do get a copy, I'd like a look (p-p-p-please!) as I might look at replacing some of the in-path components.

jeff mai 14th August 2007 07:45 AM

No help on modding, but beware of "eye-balling" virtually any setting on this unit. I used one for awhile and the front panel markings were no indication of what the unit did electrically. Any change to levels or crossover frequencies needed to be measured which was rather inconvenient!

OzMikeH 14th August 2007 09:59 AM

Thanks guys.

Cloth ears you guessed right on both counts. Fostex FT17H and FE207E with phase plug. I want the crossover high where hearing isn't so good, but I'll lower the freq if the fullranger starts looking ugly. Perhaps later roll off the bottom end at 150Hz or so and run a couple of sealed 10 inch drivers. I'm getting a reasonably nice amp soon but it's only 25 watts, so easing the bottom end will keep the mids clear (and a bit louder).

These things are surprisingly cheap.
Then again I'm not suprised Jeff has to measure for that price.

Best to steer clear of these then. I'll make my own.

jeff mai 14th August 2007 10:14 AM


Originally posted by OzMikeH

These things are surprisingly cheap.
Then again I'm not suprised Jeff has to measure for that price.

Best to steer clear of these then. I'll make my own.

It might only be variances between the pots causing the issues. It isn't too bad to measure if you have a laptop and ARTA or similar. My big gripe is that I wasted over two months trying to figure out the strange problems before I decided to measure it. I was using it with a new speaker set-up and it took me a while to suspect it as the problem.

Still, I think a purpose built crossover (or a DCX2496) would be much better.

Cloth Ears 14th August 2007 11:16 PM

They're useful (and cheap) as a starting point. And, for me, they're still in use as they fulfil my needs.

Mike, I would have thought that a single (good) cap would be all the crossover that you need for the FT17H. And possibly no crossover, just a 'notch' filter to tame the stuff in the upper area of the FE207E. What do the guys on the full-range forum reckon about the FE207E? Or possibly the High Efficiency forum on AA?

Sounds like an interesting project - what are you using for bass and how are you mounting the FE207?

OzMikeH 16th August 2007 07:56 AM

I want to keep the time and phase alignment right so a passive is only a temporary solution.
There is no upper area in the FE207E. that's part of the problem.

Currently in Singular Cabinets. Theres pics about. Also of my filter.

Building some Changs shortly. very cool box
They don't need any help in the bass at normal volumes.

Moondog55 16th August 2007 11:11 AM

I had to pot a reply here as I also use the CX3400, but I must be extremely lucky?? as i do not seem to have had any problems the units were on sale at a really good price a couple of years ago.
Not as cheap now but "cheap and cheerful " solution? I would say yes and good fun to play with, excellent for DJ and parties

OzMikeH 17th August 2007 01:10 AM

Looking at this:
(Fletcher Munson curves.)

I'd actually be better off with my crossover down at about 8.5k where the typical hearing is less sensitive.

I'm going to buy a 25 watt tube amp shortly for the main amp. Looking at the HF energy content of typical music I should be able to get away with a couple of watts for the tweeter amp. I might order a T-amp if they behave themselves in the extreme high end.

Where to buy the CX3400 Behringer in Oz?

Moondog55 17th August 2007 06:55 AM

Mike, you might try Allans music, Manny's in Melbourne, I saw a couple on E*** a month ago.

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