There’s been an unfortunate development. Since 2 weeks or so both my Alesis M1’s produce a faint high pitched sine when they’re on. It’s not noise, it sounds like a pure sine (If I move around the room the interference pattern from the 2 speakers is very clear).
As far as I know nothing changed in my setup at that time.
I’ve done some troubleshooting and this is how far I got:
- Disconnect signal cable: still there
- Adjust gain knob: doesn’t change the sound
- Disconnect all other devices on the same power outlet: still there
- Move power connection to a grounded one on the same floor: still there
- Move power connection to the living room: problem solved.
Conclusion: Something is up with the power in my room, but everything else in my room works just fine. I don’t know enough about speaker electronics to say more than that. Anyone have a clue what could cause this and more importantly: how I can solve it? I’m not willing to spend much cash on a power conditioner etc, for something that worked perfectly the last 5 years or so.