Subs pop, RCA Split Cable?

Hello all, Long time browser, but first post. Yay. Anywho I'm in the process of rebuilding my system (2 Clarion SRW1245 SVC, Pioneer GM7200, wired to 2ohm) and ran into the chance to get a 3rd Clarion for real cheap, and being as i was in the middle of building a new box for the whole thing anyway, i did. Since im assuming that the pioneer is not 1.3ohm stable im going to run my old amp for a bit until i can look at something else. Not having 2 RCA outputs off of my deck i thought running a y-splitter would be a solution. When i turned the power on and off my subs all hammer at like 5hz until the music starts (or in the case of turning off, the power dies). When i turn the volume down between 1 and 0 on the deck the subs pop. All of this hits at full excursion, which the subs rarely see so im assuming that its bad and am wondering, is this just a bad set of y-splitters, or is there something else i dont know. Thanks, -Sean

It sounds like either a grounding problem, or a faulty amplifier.My ex once told me I have a perfect face for radio.