# Installing powered sub - speaker inputs and remote wire?



## HoTsHoT (Oct 2, 2012)

Hi guys, my first post here and also my first installation 

I have a powered subwoofer coming in soon, and I'm planning to hook it up to my stock receiver myself (the sub supports speaker level inputs), but I am not sure how to handle the wiring for the inputs and the remote wire. I have a few questions:

1. Most people recommend taking the rear speaker inputs to be used for the subwoofer inputs. However I still want to utilise my rear speakers. How should I wire them, and where should I make the splice?

2. How do I wire the remote wire from the receiver to the subwoofer? Or would it be better to take it directly from the fuse panel under the dashboard?

3. Since the subwoofer will be taking inputs from the rear speaker input, how would the receiver settings (bass, treble, left-right and front-rear balance) affect the subwoofer?

4. Would it be better to ground the subwoofer back to the battery, or to the chassis to avoid ground loops?

Your replies would help a noob very much. Thanks in advance!


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## schmiddr2 (Aug 10, 2009)

HoTsHoT said:


> Hi guys, my first post here and also my first installation
> 
> I have a powered subwoofer coming in soon, and I'm planning to hook it up to my stock receiver myself (the sub supports speaker level inputs), but I am not sure how to handle the wiring for the inputs and the remote wire. I have a few questions:
> 
> ...


gl...


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## HoTsHoT (Oct 2, 2012)

schmiddr2 said:


> gl...


Thanks schmiddr2. But wouldn't splicing from a channel (or both of them for that matter) cause an imbalance in terms of power draw?


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## qwertydude (Dec 22, 2008)

It won't cause an imbalance in power draw because the impedance of the speaker level inputs is very high compared to the speaker's draw which is very low so at most you're taking maybe a milliwatt of power from the speaker, likely the resistance of the wire and OEM connectors drops more power than the speaker level inputs would take.

Generally you tap the signal closer to the speaker or even from the speaker terminals if possible. The reason being is that this keeps the wire run short as possible which will minimize any possible source of noise being picked up from a long wire run. It's also a good idea if possible to use shielded wire and to ground the speaker level input ground. Speaker level inputs often consist of 5 wires L+ L-, R+ R- and a ground. Also get the polarities correct, sometimes you'll find some head units utilize a common ground for the speaker negatives, check for that and if you do have a common negative on the head unit always use that as the negatives for your inputs and if you find the subwoofer is out of phase correct it by reversing polarity on the subwoofer or use the phase switch if applicable.

Doing the above steps will ensure a noise free system that works well with the factory speakers.


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## HoTsHoT (Oct 2, 2012)

qwertydude said:


> It won't cause an imbalance in power draw because the impedance of the speaker level inputs is very high compared to the speaker's draw which is very low so at most you're taking maybe a milliwatt of power from the speaker, likely the resistance of the wire and OEM connectors drops more power than the speaker level inputs would take.
> 
> Generally you tap the signal closer to the speaker or even from the speaker terminals if possible. The reason being is that this keeps the wire run short as possible which will minimize any possible source of noise being picked up from a long wire run. It's also a good idea if possible to use shielded wire and to ground the speaker level input ground. *Speaker level inputs often consist of 5 wires L+ L-, R+ R- and a ground. Also get the polarities correct, sometimes you'll find some head units utilize a common ground for the speaker negatives, check for that and if you do have a common negative on the head unit always use that as the negatives for your inputs* and if you find the subwoofer is out of phase correct it by reversing polarity on the subwoofer or use the phase switch if applicable.
> 
> Doing the above steps will ensure a noise free system that works well with the factory speakers.


I have a page of the subwoofer that I'm installing here - the sub's remote turn on is detected from the speaker wire so there is no need to splice the remote turn on wire from the head unit.










I'm not too sure on what you meant at the grounding part though - are you saying that I should share the same grounding wire/point as the head unit for my subwoofer?

According to the manual, the sub will work fine even if a single channel from the speaker input is wired but not the other. My issue here is that how will this affect the subwoofer output when I change the left-right and front-rear fader settings?


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## qwertydude (Dec 22, 2008)

If you change the left to right the subwoofer will get quieter proportionally to how much sound comes out of the speakers, so subwoofer to mains loudness stays the same but if you mess with the fader you'll get lower output as you fade to the front. There's no avoiding that, even on most RCA input amps you still face that same issue because the RCA output on the head unit is often tied to the rear channels.


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## HoTsHoT (Oct 2, 2012)

qwertydude said:


> If you change the left to right the subwoofer will get quieter proportionally to how much sound comes out of the speakers, so subwoofer to mains loudness stays the same but if you mess with the fader you'll get lower output as you fade to the front. There's no avoiding that, even on most RCA input amps you still face that same issue because the RCA output on the head unit is often tied to the rear channels.


Thanks guys for the replies. I prefer the flexibility of adjusting the levels of my sub without affecting my fronts, so I had it hooked to the rear speakers which I spliced off, and disabled them since they were crap anyway.

So right now the sub requires a little tuning with the fronts to complement, and everything will be great for my simple setup. Thank you guys for the advice!


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## qwertydude (Dec 22, 2008)

If you remove the rear speakers you need to put a dummy resistor in place where you take the output to replace the load that was previously there or you may get noise coming in from electrical interference. Usually a 100 ohm 2 watt resistor works well.


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## sqshoestring (Jun 19, 2007)

I ran a powered sub in lots of rental cars, just tap into the speaker (woofer) wires in back and hook to power and ground close to it as you can. Most of them sense a signal and come on. Have run it without speakers and it worked fine, but it really does not affect the speaker you tap into. I have one of those alpine boxes with that goofy sub in it, should get it repaired something is not working in it. But the thing is pretty big for me to use.


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