I had a question similar.... my subs do that sometimes, but its a hard rumble. my front speakers, which are externally amplified, pops when i turn the HU off. is this because the wire that powers the 6x8s isnt fused? the 0 gauge wire up front is fused, then to the distribution block and out of it the 8 gauge wire isnt fused. the 4 gauge wire for the sub amp is fused

1999 SE White AVH-P6500DVD Infinity Reference 6500CS Pioneer 5x7s Punch 360a2 Punch 500a2 Adire Tempest in a custom sealed 3.4cuft box Modded Xbox Still need Midnight Cloth Headrests... and if somebody has fold down rear seats....