Boston G2 subwoofer

[razpones]

Hi everyone

While I was walking my dogs I came across a Boston G2 subwoofer speaker for car audio at the park. Someone most have taken it off from their car and dumped it. So I took it home not just to keep the parks clean (I find all kinds of stuff when I walk my dogs, it is amazing, some at the park by my house), but also to see if I could bring it back to life. It is a very heavy and fancy looking piece of kit.
The speaker comes with 2 fuses that are supposed to protect the coil I imagine. They can be placed in two ways to be able to use 4 or 8 ohms thru. I tried to find something about the speaker, as it is the first time I see one of this ones in my life. It is very strange to me (the fuses for one, never seen a speaker with fuses). So I found out the fuses have to be 5amp fuses. Interestingly there were 2 40 amp fuses in place, they both were working fine of course.
So I imagine someone blew the thing away with those fuses in place. Now, the curious thing, which brings me here to ask, is the coil. The whole thing is very strange really, the cone is stiff and glued to what seems to be a plastic tube that might contain the coil (but I can't see the wiring of the coil anywhere) and the tube is also rigid, there is no play like any voice coil assembly would.
When I try to measure the ohms thru the speaker I don't get any reading, it is open, so i imagine the coil wherever it is, is broken, melted etc.
Do I unglue the plastic tube to try to find the coil?
Somewhere in my search for info I came across something, could this be a coil-less speaker? is there such a thing?.

 

[swechsler]

The plastic tube is called the voice coil former or bobbin, and the voice coil is wound around its outside. If the woofer doesn't move when you push on it, then either the magnet has shifted (that could happen if it was dropped) or the voice coil was burned by too much power, as you surmised. Some higher end subwoofers have replacement parts available, but as this doesn't appear to have been a super expensive speaker when new (note the stamped frame), it's unlikely that's the case here. What I'd do is measure the impedance between each black wire and each red wire (a total of four measurements). If you don't get any readings then a repair is unlikely to make economic sense. Plus, of course, Boston Acoustics is out of business.

 

[razpones]

It does look like some one tossed it across the parking lot. Measurements are all over the place, if I put a 7.5 amp fuse (smallest I have atm) across the 4ohm lines, on the negative line it goes up and down from 20 ohms to .4 ohms, sometimes it sits at 2 ohms, then drops to .4. the positive line mostly goes from 2 to .4 ohms. Seems to be open from negative to positive lines.
When i connect the fuse thru the 8 ohms line, it goes from 2.6 to .4 ohms when i measure the positive to negative connection thru the fuse.
I don't think the speaker have a chance to come back, but maybe am wrong?