Avantegarde Duo repair.

You could contact the US distributor, who I think is in Canada or the factory, but I suspect they won’t keep spares on hand given that the model has been superseded. Is it the plate amp? Those things are ubiquitous- as I remember, they are not servo type, so you should be able to swap in a replacement without spending a lot. The hard part will be getting one that is the right size, check impedance, etc.

I’m worried that my pair will die. The other alternative is to just leave the existing woofers in place and run external woofers, which give you the option to locate them separately from the horns. Note that the AG woofer is not a true sub- it goes up pretty high. Rhythmik at one point made a woofer that did that, but I’m not sure they still make it.
PS: I just checked the Rhythmik site, they do make a woofer that is adaptable for higher frequency response, which means you’ll need to add true subs to these. Depending on shop time and parts for a repair/direct replacement, this is an alternative-- I would not try to replace the existing woofers, just leave ’em disconnected.

Thanks for the suggestions. I worry that using something like a Rhythmik would create time alignment issues and I’m not sure at what frequency the bass module becomes audibly directional. I had used 2 subs with them set to 170hz and a 12 db slope. The SUB225’s were set to 170hz if I remember correctly. I like my subs to add meat to the music not slam me.

You are welcome. 

Knowing that Avantgarde would probably charge a ton for a repair, I'd look into a plate amp replacement.