Quality Zero impedance Horns?

Bill C. Buntin · Post by **Bill C. Buntin** » 21 Nov 2001 3:34 pm

Do they make such a thing? I have a couple of 15's that I would like to add horns to without going to the trouble of purchasing or building a crossover. I seem to remember years ago adding a horn that wouldn't load there by leaving the total impedance of the driver/horn combination the same as the driver alone. The horn may have had a high value capacitor on it to block frequencies below "x" hz.(Don't remember the crossover freq.) This would be for PA application about 100 watts per side. The 15"s are full range 8 ohm EV's. They just don't produce enough highs to suit me. Is this possible still or was I dreaming? Any suggestions?

Bill Terry · Post by **Bill Terry** » 21 Nov 2001 6:51 pm

Check out some sort of Piezo horn. I think Peavey sells them, if not Radio Shack probably does. Not real horn drivers, but no x-over is required and they definitely brighten up a cabinet. Lot's of lower end PA cabinets use them, just wire 'em in parallel.

I think the effective impedance is so high there is no real measurable change in the total cabinet impedance when paralleled with the woofer.

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Bill Crook · Post by **Bill Crook** » 22 Nov 2001 7:45 am

Bill.....

I must disagree with you in the matter of a capacitor being needed in a horn circuit. Eventho Piezo-electric horns are very hardy, they canot take the 200 watt or more,signal (from most amps)for an extended time without distroying the piezo element of the driver unit. I would suggest a non-polorzied capacitor in SERIES with the horn. It will not,in any,way reduce the output of the horn,but can and will keep the horn from being distroyed by a prolonged high voltage AC signal. Test by G.E. Co (I used to work for them)have proven that the high ampitude, low freq signals is what generally distroys a horn.

Look at any commerical speaker system,you will find cross-over caps in them. At the cost per unit, OEM would not include these capacitors unless necessary.

(My 2cents worth...)

[This message was edited by Bill Crook on 22 November 2001 at 07:46 AM.]

Bill Llewellyn · Post by **Bill Llewellyn** » 23 Nov 2001 11:41 pm

And yet another Bill chimes in..... (All Bills so far--I think this is a record!)

Pizo tweeters are just that, pretty much.... tweeters. Horns often cover midrange or both mid and high ranges. (Yes, there are horn tweeters, too.) If all you want to do is crisp up a "full range" 15" driver, pizo tweeters may do it. That's exactly what I did when I used to set two Radio Shack pizoelectric tweeters on top of my Roland Jazz Chorus 50 amp for keyboard work, but I'm finding I don't need the tweeters for steel. If your 15" is more a woofer (low frequencies only) than a "full range" speaker then you may need a conventional voice-coil type mid-hign range horn with a crossover network. And I'd agree with Bill

use a capacitor in series to block the low frequencies.

Incidentally, the phrase "zero impedance" equates to a dead short. What I think you meant to say is "zero load" horns.

Bill C. Buntin · Post by **Bill C. Buntin** » 24 Nov 2001 7:20 am

Thanks Bills!! You've been very helpful. Problem is now solved. Close the thread please. Regards.