Can I fix a passive radiator?

riglehart

One of the passives on my 11T has a problem. The cone has come unglued from the yellowish colored support on the back (where the magnet would be on a regular driver). The yellowish thing is the round disk that is made of flexible fabric with a hole in the middle where the back of the cone hooks onto it. The black cone still floats back and forth fine, but it has come loose in back from the yellow thing. Sorry for the wordiness, but I can't find my digital camera. I can post a pic later, if needed.

What kind of adhesive can I used to glue this back together?

unc2701

Yep you can glue it back on. Be very stingy with the glue, because you don't want to change the weight of the mechanism. Also test the glue on the foam to be sure it won't melt anything.

I did it w/ gorilla glue and only did one half of the circle at a time- to clamp it I wrapped a string around the mechanism and pulled it tight until it had set. Be careful not to get the string involved in the glue.

Good luck!

ben62670

I had the same problem. I used Elmer's around the diameter of the spider, and set a 6oz weight on the front center of the passive radiator till the glue dried. I have been cranking mine for a long time since the repair, and it has held up just fine.

heiney9

Other than a visual inspection are do you notice an sound characteristics that have changed? The reason I ask is because the my 5b's just don't seem to have the bass I remember them having. They use the same PR as the 11T's. I really don't want to pull things apart until I do the x-overs in a few weeks to look at the condition of the PR's.

H9

RuSsMaN

H9, you could have a similar issue, sure.

Have you just made a once over, and checked all the driver screws to make sure they are nice and snug? They can loosen over time, and break the seal on the 'fluid coupled' system.

Cheers,
Russ

unc2701

Yeah, do the push on the PR trick to see how well the other drivers respond. Also listen to the PR when you're pushing on it- if it's detached you'll get a slight scratchy sound/ feeling- that's the back rubbing against the spider.

heiney9

RuSsMaN wrote:

H9, you could have a similar issue, sure.

Have you just made a once over, and checked all the driver screws to make sure they are nice and snug? They can loosen over time, and break the seal on the 'fluid coupled' system.

Cheers,
Russ

Yes, I've check the screws and peformed the "push" test delicately. I have also pulled the active driver and found out perhaps someone along the line wired these out of phase (even though the correct color wires went to the correct terminals on the driver). I now have the white to (+) and blk to (-), opposite of the factory wiring and they sound better to me. I'll take a closer look in about 2 weeks when I get time to pull the x-overs, re-cap and re-wire. I'll take all drivers out and inspect for possible damage.

Since I swapped wires on the driver terminals they seem to have a better low freq, but they just aren't there. Maybe my audio memory from 15-20 years ago just isn't there. For this design and cabinet size/volume and the smallish listening area they should reach deeper. I do have them pretty flat against the wall, that can't help, but my office is pretty cramped with all the other crap I have in here and the way things are set-up.

Thanks
H9

riglehart

The reason I noticed the problem on mine where...

1) A "scratchy/fluttering" sound in the bass. This was due to the driver cone slapping up against the yellow piece it came free from.

2) When you pushed the driver in, instead of it going STRAIGHT back and forth, I could "swirl" it (like a martini glass). This made it obvious that it had come loose behind.