I was actually talking about the rcas that send the signal to the amp, not anything specifically about the amp itself or it being turned on. But.....Since it was brought up, It has everything to do with the amp in this case because if those subs start making noise without the amp turned on (and getting power to the subs) you really need to reconsider the phone you are using, and send me it so I can start using it as a cordless power supply. haha.
"The RF in a GSM phone "pluses" and its picked up by devices that aren't shielded well."
"This frequency causes audible noise in the voice band (300 -3k Hz)."
These are quotes directly from the write ups you told me to "read up on".
As I stated before Your subs shouldn't have this problem as they aren't even designed to play anything in the affected frequency range.
Also, The devices not shielded correctly they are refferring to in that article would be the rcas in this case as that is the only thing that can actually pick up a signal andsend it through the amp and then tell the sub what exactly to play.
ex. In your case the under-shielded rcas are picking up a signal from your cell-phone then the corrupted signal carries down the line and is then sent through the amp and out to the sub.
This why I asked you what rca's you had running to your amp, because if the cell phone is the problem then you have significantly undershielded cables and they are the weakest link.
My guess would be that you have rca's that are not even rated for car use, maybe a cheap home rated version. I am not saying this your fault or that you use shoddy products, so do not take it as me bad mouthing you.
I am not an e-thug nor do I like arguing over the internet, but I do like playing devil's advocate and letting people understand my thinking and also understanding their thoughts on certain things also.