hispls 5,000+ posts
CarAudio.com Veteran
1st off 1200rms only for a 3" coil is wayyyyyy off. my 4 layers handle more than that in a motor with poor cooling and my 8 layers handle wayyyy more than that.
ur probley clipping the amp or voltage dropping low, test with dmm...
Sine wave, clamped power, indefinitely, I'll stand by right around 1200. I got that figure from a reliable source and it seems consistant with my testing. As you get beyond that it's just a function of time before you run into thermal problems.