Discovered something weird about my setup today

[KaeZoo 10+ year member]

Leaving the RCA unplugged won't damage anything. You might want to adjust the gains and bass boost for the new output level.

Fixing the problem requires locating the LOC, then reversing the wires connected to one of the speaker outputs. It's likely, but not certain, that the LOC is placed behind the head unit.

Just to give you an idea, you have to double the output power to create a noticeable increase in subwoofer volume. Obviously, you can easily tell the difference with one RCA unplugged; that means the just disconnecting the RCA cable is making the amp produce at least twice as much wattage as it did before. Your first estimate was that there was a 10dB increase in volume; if that's accurate, that means the amplifier is producing TEN TIMES as much power as with both cables hooked up. That should not be happening.

 

[bballer123 10+ year member]

Just to give you an idea, you have to double the output power to create a noticeable increase in subwoofer volume. Obviously, you can easily tell the difference with one RCA unplugged; that means the just disconnecting the RCA cable is making the amp produce at least twice as much wattage as it did before. Your first estimate was that there was a 10dB increase in volume; if that's accurate, that means the amplifier is producing TEN TIMES as much power as with both cables hooked up. That should not be happening.

Yeah I tried to keep that in mind. 10 db may have been a little high but I can almost gaurentee its at least 6 or 7 db jump. It's definately more than "noticeable". Like when I sat in the back seat at 3/4 volume before, it was loud, but nothing obnoxious. Now it is louder in the front that it was before in the back and when I sit in the back now, I feel the bass inside my ears. I don't have any type of meter to test it but it is a HUGE increase by just unplugging one wire.

THanks.

 

[amartin_72]

Its obvious that the LOC is miswired. An amplifier puts out AC signals which alternate from positive to negative back and forth at different frequencies. If one of the signals is telling the amp to push the sub OUT and the otherone is saying IN. then they are cancelling. taking out one of them will make it louder.

If you have two channels of signal from the deck they are sending out aproximatley the same AC Signal. When your amp sums the mismatched signals inside they are out of phase and cancel eachother out. If you have a home stereo with two subs try mismatching the wires on one sub/speaker and listening to it, barely any bass at all. When you have the inputs out of phase your cancelling your input before it is even amplified. WHen you fade it left or right it attenuates the other signal that is cancelling the oppisite signal, hence more output. When you unhook one of them, the sub is then playing only the one signal and it is better than the summed signal that is fighting itself from the two exactly opposite inputs.

Get it re-wired, somehow.

 

[NickCR 10+ year member]

I think considering the issues your dad had with the shop it was for good reasons. They obiously are not very good at installations. If I were you I would take the car to another shop that is reputable. Especially if the guy "manager" is not working with you to fix the problem. Even if after all this b/s they finally "accept" the issue that there is a problem you can't know if they might screw up something else because they are a bunch of morons.