Blower buzzing over one tower speaker

[Bigjackamo]

I recently added tower speakers and notice this weekend that when running the blower, one tower speaker buzzed. The amp is not wired to the blower but on it's own stereo breaker. Anyone know why this could be happening or is this normal. Dont recall it doing that before I added tower speakers.

[NautiqueJeff]

Is the speaker wire for that speaker run close to the power wire for the blower?

[EarmarkMarine]

Its very unusual that speaker wires would pick up induced noise by being in close proximity to a blower or other motor/magnetic field source unless a passive crossover with a coil/inductor was very close by. This wouldn't normally apply to a tower speaker. And, typically both channels of a tower speaker harness would be run together making noise in a single channel improbable. Not always but normally if its an amplifier defect or failure you would have the noise in both channels.
My guess would be that one channel of one RCA cable is not seated entirely or has a bad shield connection internally.
The easiest way to proceed is to a) reverse the RCA cables at the input to the amplifier and b) reverse the speaker wires at the output of the amplifier. If needed you can rotate the RCA connections at the source or EQ. This procedure should reveal if the noise is in the source electronics, source RCA to amplifier link, amplifier or a tower speaker harness short or physical path related to a noise source. Its a basic trial and error, isolation and elimination process not requiring tools for now.
If its an older amplifier you could even spray down the input sensitivity pot with tuner wash. While there is only a common gain adjustment there can be separate and stacked pots for each channel.
Put your ear directly to the in-boat speakers without the tower playing to verify that the noise isn't present everywhere only at a much lower level.
There's a possibilty that one tower speaker tweeter is inoperative so that the noise is only prominent in one speaker.
That's the short list. One of these steps should provide an easy solution.

David
Earmark Marine

[Bigjackamo]

The speaker wires to the tower are together going up the tower and they are not anywhere near the blower or wires that run the blower (actually on the other side of the boat).

I will try the RCA's, that very we could be the issue.

Thanks to both of you for your help. I'll post what I find to let others know if they are possibly having the same issue.