weird feedback thru subs on pioneer hu

so i've had my system completed for about 8 months or so now but lately i have this weird feedback going through my subs at low volume and sometimes during a song. its just like a random thump-thump thump-thumpppp-thump-thump back n forth...sometimes it goes away and sometimes its quick. i tried resetting the radio today and i thought that fixed it but it came back on today.

i have a pioneer deh-p7000bt receiver, rockford p3 12s (2), rockford p400-4 and p1000-1bd and rockford 3sixty.2. everything is monster cables.

i first noticed the problem when i was talking on bluetooth thru my phone. typing this now makes me think it might be my phone because it never did this before on my old phone but they don't make that phone anymore. i have a samsung phone now and i had a nokia phone before.

i was thinking of swapping the radio but could it be something else? any advice is greatly appreciated.