Trying out a BSS 360 crossover that I was thinking of buying, on my 2 Yorkville 18's, rated for 800w each, max program.

Running through a frequency sweep, at what I thought were levels well within safety, as well as the bins having circuit breakers(lol).

 Sweep hits a little lower than most, dropping down to 25hz, which rippled through, fast and loud(er), causing smoke to start curling out of the back.

Am I correct in assuming that these are done for?

Do they still play? You may have gotten them hot enough from lack of excursion at tuning + high power applied to get some of the extra glues burnt off of the former. If you got the coil too hot, you could damage the coating on the wire.

First before hooking these back up to an amplifier, I would check the  DC resistance of each with a multimeter. If you don't own one, you may find a friend that does. Hopefully they read within normal specifications and not 'open' IE no continuity or '0' resistance IE: dead short.

As long as they both read a 'normal' resistance when you check each cabinet, you should be OK to hook them up to an amp and use them. Most pro sound stuff will withstand over 400 degrees F coil temps, before failure. 

If you call Yorkville, I am sure they could give you the 'expected normal' DC resistance of each cabinet.

 This is a picture of a 3" diameter coil from a driver that had been punished for many hours ( 7 hours ) at clipping levels on a QSC 3.1KW rated amplifer. The driver was in a sealed box of 3.3 cubic feet, and has a detatchable basket ( motor is removable from the top assembly )

The coil former has gotten hot enough that the black anodizing has changed color, yet the coil is fine. Some of the extra epoxy above the coil has gotten hot enough it has bubbled and burned some off. 

I have a feeling that your boxes will be OK. 

 The outside of the same coil... no issues. 

there is a barbecue.

Jacksonbart, Thanks for the helpful "Links"...yummy!

Some may think you are a clown and I do too, but I like clowns and have been known to do a little "red nose", useless humor/comments as well.

Top notch!

 Michael Hurd, Much more useful info, which is normal for a fellow Canuck and I truly hope you are correct.

I'll keep everyone updated.

At least it wasn't with any Klipsch products!

I think I'll pass on that BSS FDS 360 crossover though, probably not the cause, but don't think I can ever look at that unit again without starting to cry.

Oh happy day!

I think I found the problem and it's not what I thought.

Removed the crossover from the chain and ran bass bins full range to see if I could hear any damage to the coil.

Ran for a few minutes, from low up to regular levels and then from the corner of my eye...SMOKE!

Why am I happy to see more smoke?

'Cause when I looked this time, I saw the smoke was not coming from the speaker, but a bad splice!

Was just arcin' and burning up, when there was higher power, lucky I didn't pooch the QSC or the driver in the process, but think that may be to blame for cooking my TOA 15" a month ago.

Solder or for that matter, brand new cables are a hell of alot cheaper than new drivers!

Lesson learned, but I'm still not gonna buy that crossover, it's cursed!LOL

Thank you all who tried to help or at least made me laugh during these dark hours.

Now, on to getting those 3002's and 4002's here and running!