# Blown horn on PA cabs



## yingmin (Jan 29, 2009)

I have a pair of JBL TR225 2x15 cabs that I've owned for several years. I'm pretty sure the horns are blown on both of them, because I get a really obnoxious crackle and hiss, especially on quiet parts. I can't afford to replace the cabs themselves right now, so I'm looking for another solution. Specifically, I'm looking for the laziest, cheapest solution there is. To that end, I've considered just desoldering the lead from the horn from the crossover. My question is whether or not that would affect the impedance, because if I can't afford to replace cabs, I certainly can't afford to replace a power amp explodified by impedance mismatching. I'm a couple states away from my gear right now, but if I remember correctly, the power amp has a 4 ohm minimum, and the cabs are 8 ohms each. Any thoughts? I haven't really looked into buying replacement horns yet. See above for explanation.


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## Sippin40oz (Jan 31, 2009)

Is the horn built in? or can it be removed? horns are very cheap if you just want to replace them. I did this recently on my 2x15s and was a pretty easy job! cost me bout &#163;15 ($20-30)


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## Randy (Jan 31, 2009)

^


Parts-Express.com - Speakers, Speaker Building, Home Audio and Video, Pro Audio, Electronic Parts & Accessories is your friend. 

Horns (or specifically, the drivers in them) are reasonably cheap, and easy to replace. Make sure you check the crossover to make sure the lead to your horn isn't burned out and that's what's causing what you're hearing. Also, diagnose what caused it in the first place so that it doesn't happen again. I noticed that having the ground/lift set incorrectly on your poweramp for prolonged periods of time have something to do with it at times.

FWIW, my guess is that the components are both 16 ohms a piece, rather than 4 ohms but that's just a guess.


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## yingmin (Feb 1, 2009)

Thanks for the input. I just googled the schematics of my cabs and looked for the exact part that's included. The results I'm finding for that specific part (2412H) are all $70-80 each, but I'm sure I could substitute it for a comparable but cheaper driver.

edit: after further looking, this raises a different question: do I need to replace the entire driver, or could I get by replacing the diaphragm, which seems to be much, much cheaper? How would I know if I needed to replace one or the other?


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## Randy (Feb 3, 2009)

FWIW, I've always replaced the entire driver with a comparable but reasonably cheaper priced unit. Not sure about the reliability of replacing just the diaphragm, especially since that might not necessarily be the problem.


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