Hi Alec. Yeah all the other mid/tops and subs work perfectly. The light is on constant red, as soon as it is powered, even when there is no signal being sent to the speaker. I was wondering if it was the driver that was faulty but I was just trying to isolate the problem before I go spending money on something that doesn't fix it. Its a pretty old system and from what I gather has been all over the world and worked pretty hard. Judging by some of the other gear I bought from the same guy it could well have been been pushed too hard, he seemed like the kind of guy that had all the gear and no idea. Do you know if there is a way of manually deactivating the HF limiter or is it just something that kicks in automatically?