JL Stealthbox Install - Tips and Tricks

[stokey]

Is anyone on this forum making this harness for purchase?

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[myMUSICveins]

Most good amps have high level inputs correct?

Wouldn’t I just need to tap into a full range signal pre amp right from the headunit and run it straight to an external amp for a sub?

I didn’t see exactly where you were getting that signal from

 

[mikes2017gt]

It really depends. Some great amps don't have high level inputs. I think my JL XD600 is a very nice amp, but it only has low-level RCA inputs, hence me needing a line output converter (LOC). Both pictured here along with a "final product." Shame all my original pics that I put in the OP got ganked by Photobucket. :(

 

[myMUSICveins]

It really depends. Some great amps don't have high level inputs. I think my JL XD600 is a very nice amp, but it only has low-level RCA inputs, hence me needing a line output converter (LOC). Both pictured here along with a "final product." Shame all my original pics that I put in the OP got ganked by Photobucket. :(

That second picture is really close to showing me what I need.

Are you at the driver side kick panel or drivers door?? If I knew what specific harness and colored wires to steal signal from...

Did you have diagram so you knew where to get the preamp signals right from the HU?

 

[mikes2017gt]

You mean the picture of the LOC? I'm grabbing the signal from the wiring harness that runs next to the right deck speaker. I don't remember what color the wires are, but you can see three of them in the pic clearly. I uploaded the instructions from the PAC-SNI35 LOC I'm using as well. Once you cut open the black tape that wraps the wires/harness you can trace the wires very easily to which speaker they go to.

 

[myMUSICveins]

You mean the picture of the LOC? I'm grabbing the signal from the wiring harness that runs next to the right deck speaker. I don't remember what color the wires are, but you can see three of them in the pic clearly. I uploaded the instructions from the PAC-SNI35 LOC I'm using as well. Once you cut open the black tape that wraps the wires/harness you can trace the wires very easily to which speaker they go to.

So you are getting the signal for your LOC at the back speaker deck?

You had said in your original post

“My car is a premium so I decided to go the route of grabbing signals pre-amp. It was easy enough to get to in the drivers foot well“

I had assumed you were getting signal there at the driver foot well/kick panel

The spot you ended up using at the back speaker deck, is that still pre amp?

 

[mikes2017gt]

@myMUSICveins: I'm not the OP in this thread. The OP made a super-slick harness to grab the signal pre-amp in the driver's footwell...I am not that cool.

 

[myMUSICveins]

@myMUSICveins: I'm not the OP in this thread. The OP made a super-slick harness to grab the signal pre-amp in the driver's footwell...I am not that cool.

Ah, that explains my confusion. Thanks for the input. I don’t know for sure but I think grabbing it at the back deck isn’t a full range signal and also has bass roll off at higher volumes?

The JL Audio JX250 amp I’m looking at has high level inputs so I may not even need a LOC or a line driver if I can figure out where to take the signal from (preamp)

 

[mikes2017gt]

I was concerned about the same hi-pass allegedly applied to the rear speakers (I'm sure there's one but I've not measured) and my worries were unfounded. Now, if you're looking for 25Hz or something really low like that for competition or giggles, you may have a problem, but I have the bass on the HU at about 65% or so and I have no issues getting real thump out of rap, techno or other low-bass-containing music. Most non-EDM music's low bass bottoms out around 40-45Hz.

BTW, if you tap the signal off the rear speakers, the HU fader has a large impact on the voltage getting from your tapped point to the amp's inputs. You can make up for that with the gain control on the amp. I can't say I have a competition-level soundstage, but my image is decidedly on the dashboard somewhere and I have good bass to boot. FWIW, IIRC, I have the gain on my JL amp set at about 65-70% or so.

 

[myMUSICveins]

I was concerned about the same hi-pass allegedly applied to the rear speakers (I'm sure there's one but I've not measured) and my worries were unfounded. Now, if you're looking for 25Hz or something really low like that for competition or giggles, you may have a problem, but I have the bass on the HU at about 65% or so and I have no issues getting real thump out of rap, techno or other low-bass-containing music. Most non-EDM music's low bass bottoms out around 40-45Hz.

BTW, if you tap the signal off the rear speakers, the HU fader has a large impact on the voltage getting from your tapped point to the amp's inputs. You can make up for that with the gain control on the amp. I can't say I have a competition-level soundstage, but my image is decidedly on the dashboard somewhere and I have good bass to boot. FWIW, IIRC, I have the gain on my JL amp set at about 65-70% or so.

Ok thanks for the info. I’ll be messing with my setup soon enough. Just need to decide where I’m getting the signal from.

 

[19 GT Premium]

Is anyone on this forum making this harness for purchase?

I'd be interested in one of these harness's as well.
Tapping into the signal straight from the head unit would take away any concerns of the low end rolloff in the amp.

 

[myMUSICveins]

Just wanted to post an update in case anyone would find the info useful.

I was able to successfully take the signal pre amp from the drivers kick panel. The smallest connector was where I took the pre amp signal which was coming directly from the HU

I tapped into the front left and right speaker wires and ran wires back to my JL LoC and then sent that to my JL mono amp which feeds the JL stealbox.

As expected the stock 9 speaker system sounds pretty decent with the addition of some low end from the JL 12”

I have the “gain” on the JL LoC at 100% (the pre amp signal is not amplified) the amp at about 30% gain crossed at 50hz and the bass setting on the headunit about 3 clicks up from the minimum (so below the mid/half point)

I do this to ease the load on the stock door “woofers” for higher volumes.

 

[FreedomPenguin]

I just bought an 17 Ecoboost premium, non shaker pro model. I have a JL stealthbox in another car and it sounds phenomenal. How are you liking the box in the mustang? I have a stock system, do you hear the base in the cabin clean and clear behind seats and everything being in the trunk? Would you do it again if you had the choice?

If I can get away with it, id like to add the box, and maybe swap 2 speakers out for coaxials, assuming the difference between 9 and 12 speaker system is 2 of them are coaxial speakers, right? anyone know which ones.

 

[myMUSICveins]

I just bought an 17 Ecoboost premium, non shaker pro model. I have a JL stealthbox in another car and it sounds phenomenal. How are you liking the box in the mustang? I have a stock system, do you hear the base in the cabin clean and clear behind seats and everything being in the trunk? Would you do it again if you had the choice?

If I can get away with it, id like to add the box, and maybe swap 2 speakers out for coaxials, assuming the difference between 9 and 12 speaker system is 2 of them are coaxial speakers, right? anyone know which ones.

Definitely worth it definitely would do it again. Obviously stealthboxes are much more expensive for me it was worth it to keep it clean and retain trunk space.

I ended up keeping the bass/mid/treble settings in the middle (default position) on the headunit and kept the gain on the amp around 30% plenty of bass. Changed to crossover to 100hz to make sure I still hear a little of the punch from the upper frequency bass

I also use the Spotify EQ and pulled some 50hz down since it’s a little peaky there and also pulled some 2.5k since that part of the spectrum is harsh at higher volumes.

 

[FreedomPenguin]

Definitely worth it definitely would do it again. Obviously stealthboxes are much more expensive for me it was worth it to keep it clean and retain trunk space.

I ended up keeping the bass/mid/treble settings in the middle (default position) on the headunit and kept the gain on the amp around 30% plenty of bass. Changed to crossover to 100hz to make sure I still hear a little of the punch from the upper frequency bass

I also use the Spotify EQ and pulled some 50hz down since it’s a little peaky there and also pulled some 2.5k since that part of the spectrum is harsh at higher volumes.

Have the 9 speaker or 12 speaker upgrade? if you have the 9, did you do any other changes to your system to make it sound good? or 9 stock + 1 sub sounds pretty good? (just now getting into this information, I am reading people changing out the middle speaker on the stock system makes an improvement quite a bit.)

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