Oh my god I have got the EXACT same problem with mine and it started two days ago. The low-end of my left driver has died and I can hear a little rattling. I'm devastated. I'm assuming it's because I constantly listen to it every day with the bass port 100% open?Is there somewhere that repairs the ASG 2.5's still? My left side driver has started showing signs of rattling from what I can hear, as well as the low end going out on the left side every once in a while.
I'll email those folk at fender as well and see what they can do... Bought mine at the end of 2016 though. How long are these things supposed to last?