Subwoofer install using rear speaker wires, no cutting or speaker panel removal

[AVC]

I did it and it shows that it's now set to flat EQ in forscan. Although when I fade to only the back speakers there's no noticeable difference in bass output like at all still lacking base on the rear speakers. I think when I do add my amp and sub I'm going to tap the fronts just to be sure I'm getting a full range signal.

I mean not even one single vibration at all, I know they're only 4-in OEM speakers but they should have at least the slightest bit of base output unless it's being completely cut off.

For my XLT, I have a 6.5" Kicker sub behind the back seat. With Forscan set to "flat EQ" you get full range to back speakers and work very well and convenient as the taps for the sub. The factory rear speakers have a capacitor at them, which rolls off LF when they are being used with factory settings, as there is a VERY substantial LF boost around 60Hz.

It's worthwhile to remove the capacitors if you leave the system in "flat EQ" mode., as it will restore some mid-bass, which you will find lacking in "flat EQ" mode.

The sub wont make up the mid-bass loss without also exciting a natural 67Hz peak from cabin resonance. The sub low pass has to be kept below 55Hz to prevent that excitation.

I will also note that in "flat EQ" mode, there is a rather broad dip in acoustic response between 200Hz and 600 Hz (my memory of it), that sucks the meat out of voices and many instruments, which you can partially restore by boosting the BASS and MID EQ settings on the head unit. "flat EQ" also causes a high frequency roll-off, which you can largely compenstate by boosting the head unit TREBLE.

** "flat EQ" appears to mean NO EQ applied to speakers, which means the resulting acoustic response is whatever the speakers produce natively in the cavities they are mounted. As noted above, I could use the head unit tone settings to largely bring the acoustic response back in line, and also blending in the new sub with careful low pass and level settings.

My goal (personal challenge) with the XLT was to add a sub, with NO ADDITIONAL speakers or parts, and then settings available from the head unit and the powered sub. I'll publish my process and results in the near future.

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[Aisar]

EDIT: I discovered I gave some bad info. The left rear and right rear speakers are on their respective sides. So the left wires (grey/violet and brown/green) are under the driver side panel. The right wires (green/violet and solid grey) are under the passenger side panel. I included a picture of the right side wires.

As title states, I made a .4 cubic foot box with a dual voice coil 8" sub power by a Plinius Mono block Class D amp. I kinda went cheap but was very pleased. This little guy moves some serious bass.

Basically remove the rear driver side panel, pry up the white plastic wire cover, and the Left rear is grey/violet+ and brown/green-. Do the same thing to the passenger side rear panel and the Right rear is green/violet+ and solid grey-. Bought some Posi-Taps, wired into the high level inputs, ran a power supply to battery and ground to existing battery ground. For insurance, I used an inline 30 amp push button circuit breaker. I've heard some of these amps will come on when not in use and drain the battery. Just push the button and no power. And yes, I was in a hurry so I custom wrapped my box with a Dunkin Donuts tee shirt.

Edit to the edit: @jewc75 pointed out that by tapping into the rear speakers you won't get full bass range. I did a bass frequency sweep from 200hz down to 10hz and all bass dropped from my sub around 45hz. For most people you might not notice but you are cutting out some of the deeper bass notes if you use the rear tap. The way around this is thru Fordscan or just tapping into the front speakers. I'll leave this post up for those who still want to tap into the rear. Thanks again @jewc75 for making us aware

Hello, May you tell me how do you get the remote signal for your amp? I know there are some converters that do the job, but I found a lot of complaints for each one. Thanks.

 

[Toddman45]

Hello, May you tell me how do you get the remote signal for your amp? I know there are some converters that do the job, but I found a lot of complaints for each one. Thanks.

Some amps will not only use a remote turn on wire for its signal but also high level inputs which are the signals from a vehicles speaker wire.

 

[Carlitos_92]

The factory rear speakers have a capacitor at them, which rolls off LF when they are being used with factory settings, as there is a VERY substantial LF boost around 60Hz.

It's worthwhile to remove the capacitors if you leave the system in "flat EQ" mode., as it will restore some mid-bass, which you will find lacking in "flat EQ" mode.

I think I claimed in another thread that the rear speakers didn't have physical crossovers, but it sounds like maybe they do... I never in a million years would have assumed that Ford would use processing to BOOST bass all around and then whittle it back down selectively with capacitors.

I really can't wait to get rid of all the Ford EQ settings and capacitors (AND SPEAKERS) and put a system with a DSP in my truck. The stock setup has got some real Rube Goldberg-esque shenanigans.

 

[Aisar]

Some amps will not only use a remote turn on wire for its signal but also high level inputs which are the signals from a vehicles speaker wire.

Ah ok, thank you.

 

[AVC]

I think I claimed in another thread that the rear speakers didn't have physical crossovers, but it sounds like maybe they do... I never in a million years would have assumed that Ford would use processing to BOOST bass all around and then whittle it back down selectively with capacitors.

I really can't wait to get rid of all the Ford EQ settings and capacitors (AND SPEAKERS) and put a system with a DSP in my truck. The stock setup has got some real Rube Goldberg-esque shenanigans.

For the $1.25 the engineers were likely budgeted for the XL/XLT entertainment systems and speakers and the (likely) very limited processing capability of the non-Sync 3 system, applying overall filters and boost to all channels and then using capacitors to protect small speakers (dash tweets and rears) for excess LF boost, I would have made similar design choices.

Now that I have a sub doing the heavy lifting for LF, I'll (someday) experiment with the rear speakers to see if they can be used to fill in the last bits of the mid-bass--low-mid suckout.

While a low priced DSP (parts express) could be inserted between the head unit and the ACM, I'll not experiment with that until my extended bumper-bumper warranty expires.

Again, my goal with this phase of improvement was working with the base system and speakers as much as possible.

 

[burtbrn]

So I tapped my rear speakers the other day for a powered sub install and the sub isn’t powering on and I’m only getting 22 mili volts at my taps. What am I doing wrong?

 

[Toddman45]

So I tapped my rear speakers the other day for a powered sub install and the sub isn’t powering on and I’m only getting 22 mili volts at my taps. What am I doing wrong?

What amp are you using?

 

[burtbrn]

So it’s a cheap powered sub I got off a friend. It says it’s made by bermans. The install instructions say it will work off high level inputs and what I’ve read online the high level inputs should be around 12vdc but I’m only reading 22mvdc.

 

[Toddman45]

So it’s a cheap powered sub I got off a friend. It says it’s made by brenner. The install instructions say it will work off high level inputs and what I’ve read online the high level inputs should be around 12vdc but I’m only reading 22mvdc.

Can you post a picture of it as well as a model number for reference?

 

[burtbrn]

I will try to post a picture this evening.

 

[AVC]

For my XLT, I have a 6.5" Kicker sub behind the back seat. With Forscan set to "flat EQ" you get full range to back speakers and work very well and convenient as the taps for the sub. The factory rear speakers have a capacitor at them, which rolls off LF when they are being used with factory settings, as there is a VERY substantial LF boost around 60Hz.

It's worthwhile to remove the capacitors if you leave the system in "flat EQ" mode., as it will restore some mid-bass, which you will find lacking in "flat EQ" mode.

The sub wont make up the mid-bass loss without also exciting a natural 67Hz peak from cabin resonance. The sub low pass has to be kept below 55Hz to prevent that excitation.

I will also note that in "flat EQ" mode, there is a rather broad dip in acoustic response between 200Hz and 600 Hz (my memory of it), that sucks the meat out of voices and many instruments, which you can partially restore by boosting the BASS and MID EQ settings on the head unit. "flat EQ" also causes a high frequency roll-off, which you can largely compensate by boosting the head unit TREBLE.

** "flat EQ" appears to mean NO EQ applied to speakers, which means the resulting acoustic response is whatever the speakers produce natively in the cavities they are mounted. As noted above, I could use the head unit tone settings to largely bring the acoustic response back in line, and also blending in the new sub with careful low pass and level settings.

My goal (personal challenge) with the XLT was to add a sub, with NO ADDITIONAL speakers or parts, and then settings available from the head unit and the powered sub. I'll publish my process and results in the near future.

Posted here, for those with XL/XLT systems, and adding a sub, but keeping the factory dash, door and rear speakers

https://www.mavericktruckclub.com/forum/threads/forscan-flat-eq-before-key200-4.37908/post-956818

 

[burtbrn]

This is the sub. I’ve really got no info on it other than what you see there.

 

[DrNoobNStein]

@burtbrn
That should work as long as it powers up and gets the high input signal. To ensure you tapped off the right wires you can hook up the taps to the +/- of any old cheap speaker to verify you have sound. The high level amplifier should come right on as soon as it detects a voltage input. Also make sure the sound profile from the head unit is set to All Seats and not Driver Only. Keep us posted

 

[Toddman45]

This is the sub. I’ve really got no info on it other than what you see there.

Since you say it's not turning on, and if everything is wired properly having your power wire from the battery your ground to the chassis and then your speaker taps going from the rear speakers to the speaker inputs on the sub amp. I would check the fuses on it and make sure they're not blown.

Since there's no model number or any real info to go by for that AIO. Also is there a switch somewhere to select for the trigger or high level inputs for turning it on?

Also can you post a full shot of the side inputs and outputs, of what you have connected?

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