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Metallic "tick" from altec horn?

similost

similost

Rockin and Rollin....
OK.. I've got an issue with one of my horns and can't figure it out... These are 902-8b on 811b horns

Volume level doesn't matter.. low volume, high volume, in between. Nothing makes it worse, or less, but every now and then I will get a metallic tick sound out of it... hard to describe. Maybe like solid wires ticking together, or a very slight tap on a piece of 1/4" aluminum with a thin metal rod.. it sounds kinda hollow, and like light metals..

Bugging the hell outta me I can't figure it out. The horn sounds great. no distortion, sounds equal levels to the other horn.. nothing to make me think it's the diaphragm.. but then I've never heard over excursion on a horn. BUt I don't think so, because like I said, it will happen at low volumes too..

Ideas?
 
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Swap the horns and see if the ticking follows the horn.

Let's determine whether it's the horn/driver, or a source component.

What XO point and slope are you using?

Above 800hz the voice coils should smoke before over excursion occurs.

Are you sure the "tick" is signal induced?

Is the horn in question exposed to a window or heat source?

If the horns are solidly mounted, they will sometimes make noise due to expansion and contraction. Padding all mechanical joints with felt will stop most of that type noise.

Sorry for all the questions James, just tryin to nail it down.
 
I'll swap them first and see if it follows it.. no idea why I didn't think about that, but then again, I didn't think it could be anything else.. as far a the crossover, no idea what the slope is.. I can tell you how it's constructed though and maybe you will know. It's crossed at 1200hz on the Altec's but I'm only feeding them as a wholes above 120hz

The crossovers a 4 caps in parallel, all marked in mf.. .968, .68, 5.0, and one marked 10j 25v. Then a coil going to the LF, marked 1.0 mh

All I can tell you about the crossover..

As far as mounting, right now they are just laying loose on top of the cabs, but even laying my arm over it to dampen it doesn't stop it..
 
hhmm.. interesting.. now that I've swapped the horns, I have yeat to hear it from either.. and it wasn't anything slight, it was very hearable. My wife even asked me about it last night..
 
OK James, the "J" on the one cap must be a smeared "uF", those values roughly add up to 16.5uF which would be the correct value for 1200hz 1st order.

So long as those caps are all in spec or at least close, you should be safe from overexcursion.

Do the swap so we can try to eliminate the horn/driver itself as the source.

I just wanna express my initial thought to you. When you described the sound as a "tick", it immediately has me thinking that it's transient hash from the AC power line, likely something switching. But it could also be an artifact being generated/caused by one of your source components.
 
hhmm.. interesting.. now that I've swapped the horns, I have yeat to hear it from either.. and it wasn't anything slight, it was very hearable. My wife even asked me about it last night..
Click to expand...
That would likely point to a poor/intermittent physical connection in the horns signal path............ to me.

EDIT: Also, 25 volt seems a bit low rated for a crossover cap in a system that's going to see in excess of 200watts, just my .02.
 
Yeah.. these were fresh made.. I even had to strip the ends of the wire. I guess just a nice tough the guy added to the sale.

Gonna have to keep listening though.. but still no noise.. makes me feel a lot better :)
 
I'd check and make sure the tangerine phase plug is still glued down, it sure sounds like over excursion of the phragm like the crossover wasn't working properly. Dave.

Tangerine Failure;
Altec_604-8H_PhasePlug_02-1.jpg
 
Once I've swapped the horns from side to side, the problem has gone away. Haven't heard the sound from either horn, and I had listened pretty much all night after I did.
 
Celt said:
Maybe the "tick" crawled out. :D
Click to expand...

LOL, now I have a cartoon image in my mind of a tick, hitting similost's horn with a little hammer. :D I'm glad I looked in, I was trying to figure out the values for a passive crossover (@ 1200 Hz.), and found them here. :thmbsp:
 
spaceman said:
LOL, now I have a cartoon image in my mind of a tick, hitting similost's horn with a little hammer. :D I'm glad I looked in, I was trying to figure out the values for a passive crossover (@ 1200 Hz.), and found them here. :thmbsp:
Click to expand...

You looking to build the crossovers soon? If you have a little time, I can send you mine as soon as I get my DCX.. Just not sure how soon that will be.. hoping a couple weeks.
 
dgwojo said:
I'd check and make sure the tangerine phase plug is still glued down, it sure sounds like over excursion of the phragm like the crossover wasn't working properly. Dave.

Tangerine Failure;
Altec_604-8H_PhasePlug_02-1.jpg
Click to expand...

What exactly am I looking at? That looks nothing like my horn. That looks like a paper cone driver?
 
Shine a flashlight down the throat of your horn and you'll see it, from the other side.... :yes:
 
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