problems to diagnose with set up, advice?

[cloud77 28]

I recently have taken out my Fi Q and put in another sub to test/listen to before sale. During the uninstallation of my Q I fussed with my amp / tightened conections/took rcas out but not power or ground wire/ lifted it off the amp rack exc. Upon reinstalltion of my Fi sub when volume gets high, the sub seems to be skipping out on hitting its notes/ skips. I was thinking off the bat that it was my rcas gone bad, as it has happened before. Another side of me thinks that its my electrical, maybe one of my batteries is dead and is only kept charged by the rear battery. I have a horrible but operating set up -to regular starting battery 4 gauge to battery in back which is a everstarrt marine walmart battery =(. Battery in trunk is grounded to strut ground in trunk. Big 3 upgrade has been done on stock alt. I will check all my connections today and make sure everything is good from the hood to the trunk. Is there any things that you advise checking or paying more attention to or anything I can check with a dmm. I have a crappy volt meter that's hard t read when listening to sub at high volumes +and I know its off by like. 4 volts or so. Feedback would be appreciated.

[ssh 924]

Is the amp actually shutting off when it "skips?"

Measure the voltage at the terminals on the input side of the amplifier when your at high volume.

You could also disconnect the speaker wires from the amplifier, measure the resistance, to make sure you didn't wire it differently during installation.

[cloud77 28]

First of all, thanks for your response. I don't know if the amp shuts off ill check today. Its gonna suck sitting back in the trunk with the bass beating like that. If the amp shuts off that would mean remote wire problems? Even if the amp was getting 10 volts it would still stay on, right? Im thiinking that its a ground or maybe even something under the hood with my recent big 3 upgrade. I did it not to the best cleanliness because I didn't have correct terminals exc. But its done with good wiring and clean connections gold plated terms. I wouldn't need to take the speaker wires out to check the wiring just check the screws on the amp with the wires in right? My dumbass didn't check the ohmage when putting it in, just know that its wired correctly. Don't have access to dmm but will borrow one today. Does that sound like a rca problem at all? Last resort would be to take headunit out. Still in good working condition its a n old jvc kd series maybe take out the rca wire a new one or put the rca into the rear input to the head unit and see if it still does it? How do you check rca with dmm? Can you?

[cloud77 28]

Voltage is fine from the amp 13+ while bass is up. I think my negative battery terminal up front was loose and that was what was not giving me the umph to hit those notes with vol up. As it was a lack of ground. Does that make sense?