Possible problem/fix for SP2500's

I know they're discontinued, but, thought someone might find this helpful. I live in Houston, when Harvey came through, we lost power. When the power came back on, the 2500's had the infamous lack of loudness/lack of bass problem. I happened to notice the readout on my UPS claimed an input, and output of 119 volts. I didn't think anything of it, I mean, it's 120ish, shouldn't be a problem. A few days later, they started working right again, so I thought I'd take a look at the voltage reading again. It was at 121. I'm not an electrician, and I don't know if can be related or not. When I first purchased these, they had the same problem, and they did eventually start working right. Unfortunately, I didn't look at the voltage at that time, but, it was exactly the same scenario.