amplifier question, audio expert needed

[rojizostang]

i have a two channel rockford fosgate punch 200.2 amp feeding a single 12" sub woofer connected to the rear speakers of my f150 via a high to low signal converter to the amp on the in bound side. the outbound signal is bridged at the amp and feeds a single 12" subwoofer

whenever i have only one channel on the inbound side hooked to the amp, in any of the 4 RCA receptors, (left, right, or pass thru left and right) the volume for the woofer is good as long as the balance is centered correctly, or if the balance is adjusted toward the side that's feeding the amp.

if i have both in bound feeds attached to the amp, the volume of the woofer drops probably 50% when the balance is centered, but has full volume if the balance is moved toward either the left or right sides.

can't figure out what's wrong. i had noticed that i had good volume with the woofer as i originally installed it with the exception that the volume would drop off if i moved the balance control to the right side. i diagnosed that i had a bad connection on one of the inbound wires, but when i made the repair....i lost again probably 50% of the subwoofer volume with it wired correctly and the balance centered.

confused? i am. help.

i'll load some pictures in a few minutes

 

[rojizostang]

pics

 

[Fullboogie]

I'm having trouble understanding - you're feeding the signal TO the amp via convertors coming off your rear speakers? Do I have that right? And it goes wonky when you hook up more than one signal input?

If I have that right, you may want to check the impedance of your factory radio/speakers. If they are other than 4 ohms, which may be the case, that could be your problem.

 

[007GTCS]

Can you draw a crew wiring diagram to help understand? I think I know what the problem is, but I need a better visual of how you have it wired

 

[rojizostang]

I'm having trouble understanding - you're feeding the signal TO the amp via convertors coming off your rear speakers? Do I have that right? And it goes wonky when you hook up more than one signal input?

If I have that right, you may want to check the impedance of your factory radio/speakers. If they are other than 4 ohms, which may be the case, that could be your problem.

exactly

i'll see if i can draw a picture for you guys and scan it

in the mean time, i found a car audio forum and posted the question over there. their suggestion was that it sounds like phase cancellation, and that i should switch the positive and negative feeds from one of the converters to the input side of the amp

thanks for your input and i'll let you know if they figured it out for me

 

[BadHabit2Break]

exactly

i'll see if i can draw a picture for you guys and scan it

in the mean time, i found a car audio forum and posted the question over there. their suggestion was that it sounds like phase cancellation, and that i should switch the positive and negative feeds from one of the converters to the input side of the amp

thanks for your input and i'll let you know if they figured it out for me

This would be my suggestion

 

[rojizostang]

i rolled one set of wires on the input side from the rear speakers. problem eliminated.

thanks.