# Are front and rear signals different on head units?



## xtremevette (Apr 14, 2011)

So I know this must seem like a dumb question but Iam working on creating a new system. I want to use the head units speaker outs to power the small dash speakers left and right sides and also want to use the rear speaker outputs of the head unit to power the door speakers. Question is...do head units send the same exact signal on the front and rear speaker outputs? or is there a difference? I understand left and right sides are different because of stereo imaging/separation but was just curious if head units (Pioneer AVH-5500BHS in my case) have any difference in the front to rear channels besides left and right side stereo. Wasn't sure if they do something different on the rear channels. I wouldn't want to power up my door speakers causing weird imaging by using the rear outputs if there is some difference in signals.

Any help appreciated.
Thanks


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## Jepalan (Jun 27, 2013)

Yes and no.

Most aftermarket head units can/will put the same signals on front and rear outputs, unless you have purposely altered the rear outputs by changing fader, crossover setting or mode, or by engaging processing (fake surround processing, etc) or by changing time-alignment settings (if HU has them). 

That said, some car factory head units do put out different signals on rear outputs - like maybe frequency limited signals so rears are just filling mid-bass, etc.

You should have no problem using rear outs with the pioneer unit you reference.


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## edouble101 (Dec 9, 2010)

Funny that I was asking myself this yesterday. The hu I had in mind was the Pioneer 880PRS.


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## jdsoldger (Feb 14, 2012)

I ran the tweeters off the front and woofers off the rear for a while in my car. With an aftermarket unit it should work fine.


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## minbari (Mar 3, 2011)

as Jepalan said. depends how you have it set up. if it is just front/rear stereo, then no. no difference what so ever. if you have it in "network" mode ( I think that is the pioneer term) then it acts like a 3-way crossover.


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## xtremevette (Apr 14, 2011)

thanks guys...Pioneer got back to me saying...that if a particular HD channel is broadcasting different information on the rear channels, the unit will decipher it and play it that way. They also said if a particular track was recorded with different infomration on the rear tracks, then yes it would also play those accordingly. Just thought I would pass the info along.


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## AAAAAAA (Oct 5, 2007)

also sometimes (or always? not sure) bluetooth phone only goes to the front and not the rears.


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## Jepalan (Jun 27, 2013)

AAAAAAA said:


> also sometimes (or always? not sure) bluetooth phone only goes to the front and not the rears.


Really? I've never experienced this with Bluetooth streaming music. Maybe you are referring to hands-free phone use (voices only)?


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## AAAAAAA (Oct 5, 2007)

Yes, I did say phone not music streaming.


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## CK1991 (Jul 13, 2013)

I think it depends on the unit. In general I'd say no, but it depends from unit to unit

I do know that I had a 90s high power clarion unit that had separate signals on the front and rear channels. On some songs (especially noticeable on a couple songs by The Animals) the vocals would go to the rears and the fronts would be the instruments. It was very odd sounding. I don't think it was internal processing either, as it did not do it on all (or even most) songs. Just a few.


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## pullin-gs (Jan 12, 2014)

I have a similar unit (DEH-X3500UI).
YES, rear RCA-outs IS different that fronts!!
.....and I'm pissed about it too!
When I bought the unit, It specifically said it had two sets...one for front, one for rear. OK, no problem, that is what I wanted.

Here is my beef....there is no way to set the head-unit to pass "flat" frequency output out the back line-feeds. It is set to attenuate all highs (configurable to between 50-200hz) as if it is feeding a subwoofer amp.
Well, what if you dont want to feed a subwoofer-amp????
Your hosed!
THERE IS NOT WAY to configure it to send it out the same setup (same EQ, loudness, etc. settings) as the front.

I'm very dissapointed. I'd send it back if I could. I did not get it installed until after my 14-day Amazon money-back window was up.

[/QUOTE]


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## pullin-gs (Jan 12, 2014)

Here is the fix!
It turns out I am right.....there is no place to allow for full-range outs from rear RCA jacks using the available menu settings.

There is a "hidden" menu that is only accessible by pressing/holding a key sequence upon power-up. NOWHERE is this documented. Even after a week after I called Pioneer about they could not even help.

Here is the solution (Thanks Crutchfield!):
Press & hold the “SRC/OFF” button until the unit turns off. Press & hold the master control knob until the main menu appears in the display. Turn the M.C. knob to highlight “Initial” and press in on the knob to select the option. In the resulting menu, turn the M.C. knob to highlight “SP-P/O Mode” and press in on the knob to select. Turn the M.C. knob to highlight “Rear/Rear” and press in on the knob to select the desired setting.

This option should provide full-range and fading output from the rear amplified speaker outputs & the rear pair of pre-amp outputs.

Fixed! What chaps my _ss is that this is not in the documentation at all. So even when I RTFM there was nothing to be found.


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