I finally got around to installing my sub and i'm not happy with the output at all. I have a dd 1008 sub and hifonics hifi1000.1d amp.
I set the gains according to the sticky. 475*4=1900 SQRT1900=43.5889. Closest I could get to that was 43.6 and that's with volume at 25/35. Eq on the head unit was bass +2 treble +4 subwoofer +4 all other eq was turned off. There was BBC and a sub setting 1/2 (left it at 1 which was standard) and anytime adjusting the bass/treble setting in settings it only worked for the door speakers. I used a 35hz tone since that's what my box is tuned to.
I normally listen to music at 20 but figured 25 would be nice if I actually wanted to run it full tilt for a couple of demo's. I destroyed my front speakers so all I have in is the nissan factory 4" in the rear doors. It ***** but i've kinda been getting used to it. on 20 they are loud enough and by changing bass on the HU it affects the doors and makes them sound like *** and it's just awful.
If you have any idea what could be wrong please let me know. The sub doesn't even move 1/8" and there's basically no output. I have to put my hand on the sub and there's a little vibration but not enough to tell. I though I had the polarity wrong so I switched the pos and neg wires= No difference. I used a 9v battery and on the pos wire and neg wire the sub pushes out. Switched them around and the sub goes in so I think that was maybe an issue but it still doesn't affect the output at all. There's a red wire from the sub and a dark brownish, I thought the red was pos and the brown was neg. If I did the battery trick right then they are backwards and the red is actually neg. Kinda weird.
I bought the sub off a guy on cacao and it was brand new/never used. I'm getting tired of having all these issues with my system and i'm about at the point where I just want to rip it out and say **** it.