Blown tweeter or not?

[Chris S]

So a few months ago, I was probably pushing my pair of KG 4s a little too hot. One of the tweeters started producing a scratchy distortion, but ONLY at higher volumes. Still, every time I put the volume up, it would produce that distortion. A week later, I got my pair of Chorus' and put the KG4s in the rear, but never played them since I still had to find a replacement K-74-K tweeter. Or so I thought. A friend wanted to hear the distortion so I fired them up, but amazingly, the distortion was gone! Even at the highest volumes. I did not know how it was possible, but it was good news! So I had been playing them just about every day as the rear surround speakers. 

 

Until today. The distortion returned! Just what is going on? Is the tweeter actually blown or is it possibly a problem with the crossover? Or is some kind of internal wiring to be blamed? I always thought that a blown tweeter will sound distorted at ANY volume at ANY time -- so this is perplexing to me. THanks!

[Deang]

Klipsch doesn't solder connections to the drivers - You should check them.

The network has a polyswitch (resettable fuse) which will trip before the tweeter receives an excessive amount of power.

[wvu80]

I am wondering if you are hearing a vibration that only occurs at certain frequencies.  In my case, it seemed to come and go, then be OK, then it would return.  It was driving me nuts.

 

I don't hear as well as I used to and I can't always isolate sound to a specific point, therefore it comes from everywhere and nowhere.  I had a similar problem that turned out to be a dust cap on the woofer that vibrated, but it took me a long to track it down because the dust cap looked OK but the glue was not holding.

 

I ran a frequency sweep from a Youtube vid, then it was easier to find the exact vibration, and from there to the source.

[Chris S]

I am wondering if you are hearing a vibration that only occurs at certain frequencies.  In my case, it seemed to come and go, then be OK, then it would return.  It was driving me nuts.

 

I don't hear as well as I used to and I can't always isolate sound to a specific point, therefore it comes from everywhere and nowhere.  I had a similar problem that turned out to be a dust cap on the woofer that vibrated, but it took me a long to track it down because the dust cap looked OK but the glue was not holding.

 

I ran a frequency sweep from a Youtube vid, then it was easier to find the exact vibration, and from there to the source.

 

 

Thanks for the tips! 

 

So I took apart the horn, replaced the diaphragm with an old one from that Chorus pair (I did those up with Ti diaphragms the week after I got them home back in January), and it sounded even worse! But I think it was due to the fact that tweeter diaphragm had been loosely stored in the Random Junk drawer in the kitchen for months, banging into all sorts of stuff. I'm sure that voice coil is probably dirty as well as damaged. Plus, that magnet air gap looked dirty.

 

Theoretically, if I clean up that magnet, possibly install ferrofluid (should I?), and deck it out with some fresh Ti diaphragms, it should absolutely work 100%, correct? The wiring looked to be absolutely good, the crossover looked fine, and the rest of the speaker components look perfectly good (except for the veneer -- that is another project for another day!). There isn't any way it's a "bad" magnet, right? Pretty sure it's not possible but I'm not an expert on such matters so figured I'd ask here!

[Chris S]

Btw, I've learned quite a bit about tweeters the last few days. For some reason, I thought there was a lot more to the tweeter than just that diaphragm and the magnet behind it. DIdn't really realize that the voice coil was that delicate circular copper piece until I read up on the net about tweeter design. Basically, the diaphragm itself is the driver and the magnet behind it is simply a big magnet, machined in a very precise way. Correct? The magnet itself cannot be broken, essentially, unless you physically maul it with very hard objects, right?

[Chris S]

Went ahead and cleaned the magnet real well with alcohol and a q-tip, and used the other old Chorus diaphragm. Tried to make it as pretty as possible. Sounds a lot better, but I still detect a small amount of distortion. Much better than the other 2 diaphragms though. It's listenable especially since it's a rear channel speaker. 

 

But I think I'm on the right track -- some new Ti diaphragms should do the trick. For now this'll work.