after replace my battery, i had a little noise coming out of my front speaker, i shut the car and turn on again, it turns fine.

but now the sub is kinda weak, how do i fix this

thanks

 

What head unit are you running?

If you had the sub-output gain turned up in the head unit - it likely defaulted to 0 on reset. You sub channel may not even be on or outputting a sub signal.

Need more info or you need to find your HU manual and start tweaking all your settings.

 

sounds like you didn't let the system discharge correctly when you replaced the battery... or what laurent said - check that first.. then try properly discharging and re-charging the car... you might have spiked the amp.

 

the head unit is KENWOOD KDC-X869, i set back all my previous settings, not seems to be fine, tho still feel a bit weak in base, probably just my ear problem..haha

thanks so much guys