impedance compensation for horn tweeter fundamental resonance


I am a newbie at this crossover business. I have a horn mid-tweeter that has a resonance at 514Hz:

tweeter imp curve.JPG

I would like to make a simple high pass at 2khz with a 5.6nf cap. Is there any impedance flattening circuit that will flatten the 514hz impedance peak? I think this will be beneficial to have a closer to textbook 6db rolloff, no?

The zobel RC is only good for flattening the rising impedance but not the peak, correct?



2011-01-30 5:56 pm

Could use an LCR trap. Just add a cap in series with the RL Zobel. Will have to test with your driver for appropriate value cap.

Google "PI speakers crossover". They have a good paper PDF on horn crossover that would be of value to you.

Good luck!
1st order xover

you could use a series notch filter: Series Notch Fliter Designer / Calculator ,
but why are you using a 1st order xover...??? (& what application is the speaker for?)

I've done various xover slopes and frequencies on my DBX driverack, it's very useful for that.

24db, 18, 12, and 6. Between the tweeter and mid horns, for whatever reason the 6db at 2Khz sounded the most natural, especially on vocals and acoustic instruments.

Although most pro audio uses 4th order, I found in my application I preferred the sound of 1st order crossovers. My application is general music listening, 500sq ft. room, electronic music, classical, jazz.

Also, doesn't 1st order xover provide the best transient response? maybe that is what I am hearing and I like it.

Often horns have Lpads applied which provide a parallel resistor and help filter operation. A simple parallel resistor, if you don't need adjustment range, is also a good method though lossy. Best is to do a tuned trap, but those are more effort to get right.

About 2/3 of the way down, we have a dual notch impedance compensation for JBL 2426h.