electronics confusion

[bjackman]

sorry i know there are millions of threads like this, but i've read them all.

basically, my active monitors hiss (wait! there's more!)

It definitely isn't a ground loop (it's a high frequency hissing, not a 50Hz buzz).
It isn't my signal cables (still hisses when they're unplugged).
It isn't interference from other electronics (they still hiss when i put them in other rooms)

so that's as far as my A-level physics electronics takes me.

When I first plug them in and switch them on they are silent for about 3 seconds then suddenly start hissing.
If I repeat that straight away the same thing happens, so it can't be a temperature issue (right?)
Also, the speakers have their own little volume knob. When this goes down the hiss goes down.

So if anyone can suggest a way to solve this puzzle, I would be eternally grateful. thanks.

ps they are Alesis M1Active 620s

[abZ]

My monitors dont have a volume control but rather a gain. I leave mine all the way down.

[switchdubs]

is it both monitors or just one that this is happening with? If you are getting a hiss with no signal leads plugged in at all its down to your speakers, send them back under the warranty. Thats what happened with one of my krks. Id find it very suspicious if the same fault developed in both monitors at the same time tho.

[dequo]

is it both monitors or just one that this is happening with? If you are getting a hiss with no signal leads plugged in at all its down to your speakers, send them back under the warranty. Thats what happened with one of my krks. Id find it very suspicious if the same fault developed in both monitors at the same time tho.

got this with my krk's too, both of them. apparently its radio interference

[Sharmaji]

the gain on your monitors should ideally be set to '0'-- that is, unity, they're neither amplifying nor attenuating the line signal that comes in.

in general, that'll make them EXTREMELY loud, but with the advantage that your signal-to-noise ratio is pretty much what the manufacturer says it is, and you're outside of the harmonic distortion that might occur w/ more amplification. However, you gotta do your volume control upstream, either via your soundcard or some other volume controller.