Yesterday, as I was really close to the speaker, I noticed my CSi3 was making a buzzing? rattling-like? sound when playing really low tones. I hadn't noticed this before - but the speaker has never sounded great to me - and the buzzing isn't audible at a distance.
I took off the 'cover' and put my ear up to each driver and still couldn't tell where it was coming from... but it's definitely coming from the speaker itself.
What could be causing this? Any ideas? As I said, it only occurs during very bass sounds.