i just noticed that when i play with the fader on my head unit, my sub does something weird to me. when i fade all the way to the left speakers, the sub hits like normal. when i fade all the way to the right, the sub doesnt have any output. does this mean the wiring for my right channel is disconnected somewhere? or is this just how subs function? if this is an error, is it something i need to fix or will it not affect anything? i have an alpine 12" wired by 2ohms to a monoblock alpine amp

thanks!

 

No, your wiring isn't messed up. I'm guessing that if you're using an aftermarket stereo it doesn't have a dedicated "mono sub output" RCA and you're linked into one of the "rear" channels which is a stereo output, rather than a mono low-pass out. Since you only running one sub you're only going to get sound out of one channel (Left in this case, rather than Right). Nothing to be worried about unless you really need to adjust the left/right balance on a regular basis. Set the left/right balance and adjust the amp gain as needed and then forget those settings.

Again, not an error and nothing to fix. Most folks only have a single channel for subs when all is said and done, different head units will give different adjustability and control over the sub(s), but very rarely are they wired in stereo.

 

im thinking he has an oem headunit and whoever installed the amp for the subs used a line converter and installed it on the left side. thats why its not getting any signal when he fades to the right. still, nothing wrong with the wiring.

 

i am using the OEM headunit but im leanin towards what leksikon said, thats what i was thinking as well

i installed it myself and there is no LOC, you only need one if you tap in after the factory bose amp. pre-amps dont require it. so i spliced an RCA cable into the right and left rear speaker outs from the head unit which go right to my bass control **** in the ash tray and then to the sub.

awesome i glad you said this. i was just thinking i had a loose connection on my right side but wasnt really going to worry about it because since bass is non-directional i figured there would be no difference in the right and left channel at this low of a frequency. but i thought the signals would be uniform and both send, i didnt think about it being sent out in mono.

do you think if i crank up the frequency on the amp output and then balance to the right i would hear the sub? i know for sound im fine the way i am, i just want to know if i messed up on any of the wiring or not for prides sake

 

Are you fading or balancing? You fade from front to rear and your balance from left to right.

If you connected RCA cables to both the left and right speaker you should not have any decrease in bass when you balance from left to right. If you connected them to the rear left and rear right speakers you will lose bass when you fade forward (because you are taking the signal away).

The fact that you only have one sub doesn't affect anything. The amp should be combining both left and right signals and sending them to the sub.

 

sorry typing error. i am talking about balancing left/right

is it possible that since i do have a monoblock amp, that it combines the left and right input into one output channel for the sub?

 

Thats exactly what it should be doing. Summing the left and right outputs in to one channel. If it didn't work this way there would be no point in putting to RCA jacks on the amp!

One easy test to do is swap the RCA cables on the amp. If the signal moves to the right instead of left you have an issue with the signal going to the amp. If the signal stays on the left then there is a "problem" with the amp. In reality, you most likely won't be able to hear any difference in most music as long as you have it balanced to the middle.

Something else you may want to research is if your amp has a mono input. If it does, you can feed that with one channel input and it will automatically make it both the left and right input. Since it only uses 1 RCA input if you have a bad splice in the 2nd RCA cable it won't make a difference.

 

awesome thanks for the info

if i swap the rcas and the signal stays ont he left, why would that mean i have a problem with the amp. wouldnt that mean it is just doing what it is supposed to do and taking the stereo input and outputting it mono to one channel?

 

No, it would be that the right input on your amp isn't working. The whole point of stereo inputs on a monoblock amp is to have both the left and right signal going to the amp. If the amp was only supposed to operate in mono mode there would be only one RCA input on the amp.

 

so i switched the rcas and the issue was exactly the same
but i found something else out which makes me think its not the amp

when i played with the head unit settings some more i found out my rear right signal is super weak even to the stock speakers. when i have it faded all the way back and then mess with the balance, the left side is way louder than the right. also when i am on the right side i will get a small amount of sub if i turn the sub alllll the way up.

so does this mean i just have weak connections with my right side wiring? can that cause a quieter signal instead of just no output?

 

If you switched the RCAs and the issue was exactly the same, it is theoretically different. When you balance to the left now the music has moved to the right channel. You can't hear this because its a mono sub amp, but that means that the amp if fine and there is an issue with the signal going to amp. If your right rear signal is weak then that almost has to be the source of your problem. Now the question is why is the signal weak? If you tapped in to the signal pre OEM amp then that would be the signal from the head unit is low. I would unhook the RCA splice that you made and put everything back to factory and see if that makes a difference.

 

well if my splice is just a poor connection, woudl that cause the drop in output volume to the rear right speakers? in that case i could just goin in and correct the splice and all would be great?

 

I don't think it would - I think an improper splice will be all or nothing. It is possible that if it is a two wire low voltage signal (which I think it is) if you only have one wire connected the signal will be muted.

The first step in troubleshooting something is to identify anything that has changed. The splicing of the signal is an obvious change and that is where I would start. The fact that it is an easy task to undo makes it an even better first step.

 

so i checked the splices for the right wire connection and they all looked fine but went ahead and redid them.
problem solved!
the signal to the left and right speakers is equal now and my sub is hitting sooo much harder with both signals coming in.

sadly i broke my proclip iphone mount taking the dash apart again