Loose Magnet WTF

[Daniel644]

Damnedest thing I've seen, I was having this weird thing where every once in a while the Eclipse Titanium 15 I have in my weekend/fair weather car would hit really really hard for just like a second or 2 then go back to normal so I was thinking maybe one of the wires where loose on the spring terminals, I get the sub out of the box (which is no easy feat in that car) and I come to find the magnet has begun to unscrew itself, how that happened, I don't know, but I found a torx head set screw, backed it out, reseated the magnet as tight as I could and reset the screw. have to wait till the afternoon when I take the car out to see if I fucked anything up halfway unscrewing the magnet as I tried to figure out which way was tightening.

 

anyone ever see anything like that?

[Mitchaford]

Could you by chance upload a picture?

I think you could be talking about the motor and it's separating itself from the basket. 

[Daniel644]

On 9/23/2017 at 10:15 PM, Mitchaford said:

Could you by chance upload a picture?

I think you could be talking about the motor and it's separating itself from the basket. 

it was the whole section circled in red in this attached picture, it was basically partially unscrewed (I never knew thats how it attached), like a 4-5 ish inch diameter treading was visible and you could "unscrew" it from the basket, I loosened the set screw in the basket, screwed the magnet (motor?) back on tight as I could and then re tightened the set screw to hopefully hold it in place.

[SnowDrifter]

Normally the magnets are clamped on by 6 screws, no?

[Daniel644]

4 minutes ago, SnowDrifter said:

Normally the magnets are clamped on by 6 screws, no?

thats what I always thought, but that whole assembly threads onto the basket then has a set screw through the bottom of the basket at an angle that I assume is to attempt to prevent it from backing off.

[AlpineNut]

Someone forgot to use the loctite on the screws im guessing, could be worse ive had tinsel leads litterly come apart on a 12in Crunch Fat Boy and i was not even playing the subs that hard.

[audiofanaticz]

These subs are old, very old.

To know more about the old Eclipse subs one must know that TC Sounds built them for Eclipse.

That means they most likely used QCA rings (which allows you to thread/unthread the basket from the magnet) which means if you ever blew the woofer all you had to do is order a new top half and thread it on and your good to go.
Here is a old Eclipse TI Pro motor, you can see the threaded plate, the lose gear looking thing is what is mounted in the basket and threads onto the magnet.

 

 

Here would be the top half of the Ti Pro basket/cone assembly that would thread directly onto the magnet.

 

 

Some designs have changed over models, some of the TC woofers with this feature have a removable ring on the magnet that can be removed as well.
As you can see in this photo with the 6 set screws (the 2 magnets in the rear that look the same without the set screws are the same as the above Ti pro photo).

Just google Ti qca ring or TC qca ring and look at the photos.

Ideally you wouldn't want to loctite the set screws in because it would make it a PITA to remove in such tight spaces if you ever needed a new top half assembly.

[Daniel644]

8 hours ago, audiofanaticz said:

These subs are old, very old.

 

Just google Ti qca ring or TC qca ring and look at the photos.

Ideally you wouldn't want to loctite the set screws in because it would make it a PITA to remove in such tight spaces if you ever needed a new top half assembly.

Yes it is VERY OLD, circa 2005 when I bought it  and very heavy. It was unthreading the LARGE thread of these guys (in the picture quoted) screwing off of the basket, there is a single set screw going through the bottom of the basket at an angle, that I assume is meant to be a "friction mount" to keep it from unthreading itself, I backed that set screw out and fully screwed the assembly in the quoted picture back down tight and then tightened the set screw. Hopefully it won't come loose again, had just never seen anything like that before, so it won't damage the voice coil or anything since it was designed to unscrew like that was basically my only real concern, having it back together it's hitting pretty good so I don't think anything was hurt from playing it with that assembly backed off like an 1/8".

[audiofanaticz]

Due to it being threaded on all that would happen if it came loose is you would lose output from the subwoofer since the voice coil is no longer sitting in the proper alignment of the magnet gap which would result in less excursion.

The voice coil should be fine because of how it threads on/off so at no time should the voice coil be shifted either way to rub on the inside/outside of the magnet gap.
Now if the sub didn't have the QCA rings and the basket was bolted to the magnet like all other subs are, and some bolts came loose the magnet could shift side to side or become uneven which would cause the voice coil to most likely rub on the magnet damaging the voice coil.

But thats not the issue here with these.