Tweeter works intermittently

[RampantAndroid]

Hi all,

I've got a tweeter in my car that seems to be acting up - getting the doors off the car is a real pain in the neck, so I haven't gone in there just yet.

The symptom is that one of the doors suddenly starts to sound super muddy. If I put all sound to that speaker and play a sine wave at anything from 3k up (not sure where the crossover is set) I can hear the sound isn't totally dead, but it's kind of raspy. If I turn the sound up more, it continues until suddenly...it sounds fun. Turn it back down again and it remains fine for a little while - maybe a day - and then I have to repeat the steps again. It's only that one speaker.

Now, to me that doesn't sound like a blown (or even partially blown) tweeter...it sounds like something gets stuck and then playing a louder sound frees it up for a little bit. Would this be the voice coil getting stuck inside the magnet? Or the voice coil becoming detached from the cone? Is there an easy fix, or will this likely mean needing a new tweeter?

Thanks!
RA

 

[slashbinslashbash]

Sounds to me more like a bad crossover or a loose wire somewhere than any kind of mechanical problem inside the tweeter driver.

 

[RampantAndroid]

Sounds to me more like a bad crossover or a loose wire somewhere than any kind of mechanical problem inside the tweeter driver.

OK - are you thinking cold solder joint, or are you thinking time to look at the capacitors and rebuild the crossover (assuming it's not a loose wire...which I don't think it is.)

Why would turning the volume up and back down - in absence of any other changes - resolve the issue?

The system setup is:
Audi A4 factory amp - Audio Control LC6i - Phoenix Gold SX1200.5 - Morel Maximo 6.5" 2 piece components in back (one of these is the problem) and Morel Virtus 6.5" 2 piece in front (these seem fine.)

Thanks!

 

[slashbinslashbash]

OK - are you thinking cold solder joint, or are you thinking time to look at the capacitors and rebuild the crossover (assuming it's not a loose wire...which I don't think it is.)

Test the caps and resistors with a multimeter to see that they're up to spec. For that matter, you should be able to test the driver itself to make sure it's impedence is coming out correctly.

Why would turning the volume up and back down - in absence of any other changes - resolve the issue?

My thought is that there might be a heat factor. When enough power has been pumped through the flawed component then it gets warmed up and behaves more like its designed performance. When cold then it is out of spec.

I also just really doubt that there is some kind of mechanical problem with the tweeter. There really isn't much room in there. A tweeter has a displacement measured in the thousandths of an inch, and the amount of power going through it is usually miniscule in comparison with that passing through a woofer. If there were something in there then it would be in the way all of the time and you would never have clean sound.

I suppose a super easy test would be to swap out the crossovers between the L and R sides and see if the problem stays with the same tweeter or swaps sides. Easy enough to do with component speakers.