2018 Grand Cherokee build help for beginner

sonicbooms said:

Looking to upgrade the sound in my 2018 Grand Cherokee which currently has the factory Alpine 9 speaker setup. I intend on running the factory head unit for now.

I’ve been reading the forum threads and understand I need to run a clean line out because the factory unit mixes the speakers for the current setup. For this I’ve chosen the JL FiX 86. The following are the rest of the components I’ve put together for this upgrade. Please make any suggestions as far as compatibility or if there is a better, comparable choice. Or any other tips and tricks I probably don’t know about.


Equipment:

Fronts: JL C1-690 Components

Rears: JL C1-650 Components

Sub: JL HO110-W6v3 ported wedge

Amp: JL VX1000 5i

Signal Converter: JL FiX 86

DSP: TuN built into the amp

Knob: DRC-205 adjusting sub volume

Deadening: around the speakers in the doors

4 Gauge amp kit

16 gauge speaker wire; 12 gauge to Sub?

JL Audio Fix-LSA-4 for the FiX 86 to keep the head unit from shutting down when it can’t sense a center speaker any longer? Do I need this?


Questions:

1. It says the Fix 86 gets its signal from the speaker wiring - do you just splice into the speaker wire for each speaker behind the head unit or factory amp? And then run it into the 86? And then RCAs from the 86 to the VX1000 amp? And then the new speaker wire from the VX1000 back out to the speakers?
2. Is the FiX 86 better than the PAC AmpPRO AP4-CH41 or the Rockford DSR1 which are also compatible with my car? Figure it makes sense to keep the system all JL, but wasn’t sure if it mattered.
3. Should I just disconnect the center dash speaker and built in sub? From what I understand, the VX1000 5i and TuN software will only do a stereo L/R mix? So that center channel is not compatible with that?
4. Do people ever run coaxial 2-ways in the doors and separate tweeters in the pillars as well? Is that overkill or can it be tuned well?
5. Will I miss the center dash speaker’s output or will the center soundstage with the new setup be so awesome I won’t care about that center?
6. Does it make sense to run components speakers in the rear doors since I have the rear pillars as well? I’ve seen some just run coaxials in the rear and disconnect the pillars.
7. I’ve considered Audiofrog, but they are significantly more expensive. And I like the idea of all the same brand speakers and don’t know enough about mixing them.
8. Can I make spacers to flush mount the 1” tweeters in both front and rear? I like the tweeter being less filtered and also like the badging showing.
9. I’ve seen the setups some people have done with the spare tire cavity and might do something like that one day, but want to start with something simple, which is why I chose the W6 in the premade wedge enclosure. I’ve seen some people bolt them down; I’ve been thinking velcro might work well.
10. Should I run wires in flex tubing or any other type of insulation to avoid engine noise/interference? Any recs on wire? Battery is under passenger seat so I shouldn’t pick up any noise from the engine cavity.

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Use the AmpPro, this keeps your center channel information and lets you control the volume of chimes so you don't miss the center channel and also gives you a flat digital signal. All of the factory EQ and DSP are in the OEM Amplifier so by using the AmpPro you get the original signal before all of that... This also means that you won't HAVE to disconnect the center channel and factory sub as you 'could' run them in parallel with the new JL equipment but that would likely cause all kinds of problems with Time Alignment and Phasing so the best suggestion is to disconnect them at the driver.

Yes, people have run coaxials and tweeters in the sails or pillars at the same time but it's a HUGE No No. Running multiple drivers of the same size and frequency range on the same channel causes comb filtering and that's nasty. Just don't.

The midbass in the rear door and the wideband in the D-Pillar is the about the dumbest idea that Jeep has ever had and if you want to simplify the system, then coaxials in the rear doors is a simple solution but it always irks me to have speaker grills with no sound coming from them and people asking why so I use the widebands in mine for the bulk of the sound and the midbass door speakers are bandpassed and reduced in output to the point that no one but the person sitting by that door can even tell they are there. More on the D-Pillars in a moment.

Audiofrog is a HUGE jump from JL C1 components and there are a whole bunch of drivers in between that you should consider before simply using C1 for the name. In fact, before going with C1 components, I would suggest that you install the AmpPro and the amplifier on the factory components first and see what it sounds like without all the factory filters and EQ, you will be amazed at how good they can sound with a proper tune and source.

Where are you planning to mount the amp if not in the tire well? The factory amp is in the left rear quarter and you have to remove the load floor and spare tire surround to get to it but once you do you can get a T-Harness to use the factory wiring and not have to pull all new wire through the vehicle. This also lets you return to OEM if you decide to sell down the road. 12 gauge wire is fine for the Sub.

Flush mounting the tweeters in the sail is easy, you pop out the oem grill and then modify the opening to fit the tweeter you buy, the rear D-Pillar is not as easy. The wideband that's in there is a 3.5" and you need skills to modify an opening that big to fit a small tweeter but if you've got the skills then go for it but you really should try just doing the Amp and Sub 1st to see what you've got... I think you'll be surprised.

My suggestion for mounting Subs in the rear cargo area is to do it in some way so that it can be removed easily (like the twist clamps on road boxes for touring gear) but velcro won't do and using ratchet straps would be more secure. Bolting it down to the false load floor is also problematic as it makes removing the load floor to get to the spare almost impossible for one person. But at least bolting it down is safe.

Flex tubing or any other tubing won't change interference. You only need to run power from the passenger seat to Amp mounting location. Then, Fiber Optic from the AmpPro in the dash to the JL Amp and speaker wire from the JL Amp to the OEM Amp so interference should not be an issue. Use 1/0 OFC Copper Welding Cable for the power and any reputable OFC Speaker Cable.

Deadening: once you get the door cards off you are going to see a huge plastic assembly that's fairly well sealed off to the metal door (compared to the designs of the past) but don't be fooled, to get that panel off you have to remove the window glass 1st and it is not for the faint of heart. Once you do, deadening inside the door is much easier than the previous designs and this is not where you want to skimp out. The investment you put in deadening and doing it right the 1st time will be the most cost effective improvement you make...

sonicbooms said:

Thank you so much for taking the time to write that out - many great ideas.

Using the factory speaker wiring would definitely make the install easier and smart thinking to just try wiring up an amp first to see how it sounds.

I've demoed speakers a couple times and thought the C1s sounded really clear, accurate, and warm - I liked them better than the alpine R series. I've thought about infinity reference and focal as well, but feel like the C1s are really strong performers for their price. Plus I could leave them in when I sell this car and just take the amp and sub with me.

Mounting the amp in the extra battery compartment under the front seat sounds like a super clean way to do it.

On my return run from the amp, it's just one set of speaker wires routed to the OEM amp? Thanks for explaining how those wires are run.

I have to remove my window to add deadening? Not sure I'm ready for that lol

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Alpine, Infinity, JL C1 are all on about the same level. JBL is a step up and Focal is another step (depending on the model) but there are other 6x9s that are better for the money.

Hybrid Audio Tech (HAT on the Jeep forums), CDT, Morel and of course the and during my journey I started with replacing speakers and went from JBL thru all of the drivers above and eventually settled on the Morel Ultra Tempo as they had the best overall sound. They weren't the best in any particular area but had the most even coverage by far with a 6x9 reaching up to a tweeter.

But... in the end replacing the speakers was for naught without an amp an dsp. The oem rolloff on the top end (supposedly to keep you from hearing the harshness in the satellite radio compression) and booming midbass due to an apparent 120-140 Hz boost was infuriating no matter which speakers were installed.

So then came the Helix to fix the factory filters and then an AmpPro cause the factory amp has some stuff that simply became more than I wanted to deal with but then I eventually sold that and went back to high level from the oem amp cause I learned how to better setup the Helix and figured out how to send digital Bitstream from my phone direct to the Helix. That way I can stream music direct digital from my phone and leave the HU on the unused Aux input and if the navigation or a BT cell phone call comes in the Helix autoswitches to the factory amp.

Speaker wire: you will still need to run wire for every speaker you want connected to the VXi. The factory wiring has all the speaker runs going to the amp on individual runs so there's no need to pull any wire. So 4 sets of wire to the factory amp location and one to the sub.

If you decide to go Helix check out the integrated dsp amps and then get a separate mono amp for the Sub. I already had more than enough amps on the shelf but if I was starting from scratch then a V12 would be at the top of my wish list. Then you maintain the center channel and have enough channels left over to go 3-way in the front if the bug strikes.

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sonicbooms said:

Thoughts on the AudioControl D-6.1200? It can do 5 channels and matrixing, seems like it might be a good solution for me. They also have a strong mono amp to pair with it, the LC-1.1500.

Not a Helix, but maybe a little more plug and play? And seems to have many reviews about not being noisy.

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The AC dsp is good enough to do a basic SQ setup especially if you do coax rear doors but they aren't in the same league as the others.

DSP contenders in alpha order:
Arc Audio
Helix
JL
MiniDSP
Zapco

Browse thru some of the dsp comparison threads rather than rehashing that in this thread.

Sub Amp has a fixed non-defeatable 24 Hz HP filter. Not an issue if you're going ported at anything =/> 30 Hz but it's a huge turn off for me personally cause I'm a bottom feeder and even if the only thing down there is subharmonics I simply can't abide them putting a brick wall there that I can't turn off...

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sonicbooms said:

I appreciate the comment and I've definitely had this thought! Unfortunately or fortunately, I usually dive off into the deep end lol. I'm definitely going to keep doing research before I spend money, I've already learned a lot I wasn't aware of in a short time. Ultimately you're right, the biggest driver for me is having some nice pounding bass... but the factory alpine amp is only 500 watts I believe, so I'd need more power right away. And the mids/tweets aren't bad, but almost any aftermarket speakers will be of higher quality and sound better, most likely. So I feel like if I'm adding power, might as well swap out the inferior speakers. But you're right, it quickly becomes several thousand bucks, especially if you get nice amps like Helix... which are pretty damn sexy.

Ultimately this factory head unit has to be doing the same thing in some capacity - taking a stereo L/R input and creating a center channel with a matrix of it?

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Not exactly - the factory center channel has things like GPS, Chimes and Cellular BT audio that are directly mono and only in the center channel. The actual center channel content for music is a combined LR signal and there have been many attempts to analyze the factory signal (by ear, by REW and oscilloscope) to decide if the oem content is "good enough" or if one of the upmixed dsp center solutions is better but ultimately this becomes one of those listener preferred things and what YOU expect a center channel to provide.

Ultimately IMO the oem center is a "front seat tune" as differentiated from the idea of a 2-seat tune (more mono with content meant to anchor the image between the doors vs becoming the differentiator for 2 separate listening positions simultaneously) and can totally destroy the classic 1 seat tune where there's no need to have a center. What do YOU want the center to do?

My advice to every Grand Cherokee and Durango/Citadel owner that I've spoken to is that if you can't specifically pick apart the oem center and what that center has done to destroy your image or experience then you are much better off leaving it alone and starting with the subwoofer.

ICYMI - they make a stack-fab factory sub replacement in Florida: https://store.audiodesignscg.com/product/jeep-grand-cherokee-subwoofer-box/

The stock design requires no cutting but is limited to about 20L (0.7 cuft) displacement but if you don't mind cutting sheet metal they can make it much bigger.

So to summarize:

Start with the subwoofer - if you use the AmpPro you'll be surprised at what that factory 500W amp can do by turning down the bass in the HU EQ and adding it back in with the AmpPro and/or bass EQ in whatever amp you add...

Second: look to get a replacement amplifier that can ultimately handle all the channels (there's 10 channels if you include the sub) including if you are even remotely interested in doing 3-way fronts. So that's 12 channels... WITH DSP and if that level of $$$ commitment makes you go into sticker shock then know that you should incrementally upgrade the amplifier 1st (you can compare doing high level or sharing the AmpPro if you get an amp that accepts high level inputs) and let your ears tell you whether the oem speakers are the problem or the oem filters/EQ.

Make no mitsake even for a veteran installer doing a full system change out with top shelf gear and integrating oem signals with digital is a HUGE undertaking. I've been attempting to beat mine into submission for 4 years only to realize that due to my own blind pride and stubbornness that I had the high level front tweeter inputs swapped (happened at about the 2y mark when I finally went all in with the Helix) and literally was flummoxed for 2 years at why my direct digital sounded so good but the high level input was literally like being in a drug induced haze. All of that to say that that now that I've got that SNAFU behind me and I'm able to effectively tune the oem signal that I'm VERY pleased with what the system sounds like and unlike most members here who would hear the difference between direct digital and oem signals instantly, 99% of the people I've demoed for (including my family) really can't tell a difference. But I'm like most of the long termers here and happy tuning for hours on end and taking measurements and tweaking and fiddling ad nauseum (3 decades in the audio scene) and if you simply want to be able to get in and go then totally redoing the signal chain from scratch may not be for you.

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sonicbooms said:

Are 10 channels currently used with the Alpine factory amp or are either the fronts/rears components?

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Yes - the only model that doesn't have fully active components is the base 6 speaker system so everywhere you have a driver currently (even more if you tweeters in the rear doors) has a home run of speaker cable to Factory Amplifier.

sonicbooms said:

If passive crossovers were used, that would cut the channels down to 6.

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Yes, if you do passive then that would cut the channel count down. Mine are currently passive to the front doors with the passive crossovers mounted on the amp board in the spare tire well so I can experiment between active and passive as the inclination strikes me...

sonicbooms said:

If I get a 6 channel amp (or 8-10 if needed) and then a mono amp, would I then bypass the alpine and just be adding more power to the existing channels? And then I could disconnect the sub in the back and run that speaker wire to a new subwoofer box?

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The stock speaker wiring all terminates in two different connectors (you'll see on the wiring diagrams linked above) on the factory amp and you can bypass or maintain the connection on each driver as needed by cutting into the factory harness (or using a T-Harness if you intend to be able to return to stock.) But for the sub I would expect you'll want to run new wire as the factory wires are either Dual Voice Coil or Quad Voice Coil in some years and the gauge wire used won't support big power levels.

sonicbooms said:

Can I just amplify the center and system ‘as is’ and add a mono amp and sub box as well?

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If you keep all the factory speakers and use an amplifier with high level inputs designed to accept the output of the factory amplifier then yes, but if you are intending to use passive components or coaxials then you'll need something to combine the factory component signals and sum them for a full range output.

sonicbooms said:

I would have to disconnect the existing speakers and install the new ones... and run new wires from the 4 channel amp to the new speakers.

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You install new speakers using the existing wires and then make the connection to the new amp in the rear left quarter panel where all the oem speaker wires terminate at the oem amplifier. Unless you simply WANT to run all new speaker wire but that's a huge hassle for zero gain. The factory wiring is sufficient gauge and twisted.

sonicbooms said:

Additionally, if I did this, I could STILL have my center and rear pillars running on the factory alpine amp, correct? Do I need any load resisters for the channels I disconnect?

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Correct you can use a combination of the oem amp and an aftermarket but if you use the AmpPro to feed the aftermarket amps then you are losing the factory Time Alignment. If you are going to use a combination of oem and aftermarket amps then you really should be running High Level inputs off the factory amplifier to maintain the alignment which is much more important to the imaging than factory filters and EQ.

Yes, you need load resistors for any channels you disconnect (IIRC 2014 and older models do not.)

sonicbooms said:

This is the direction I'm leaning now, review for the AmpPRO:

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The AmpPro is great for getting a clean, flat, digital signal (if you opt for the optional toslink output for an extra charge) but keep in mind that any amps you add have to share that fiber so you need linkable amplifiers or a way to split the fiber optic signal. Additionally (unless the 2018 is different from the 2014 and earlier models) you are getting a straight stereo signal with no fading, no EQ, no Filters and most importantly, NO TIME ALIGNMENT. Now for adding a subwoofer, this is generally not an issue as the factory sub is farthest away and usually the one driver that's not delayed, but as soon as you start looking to replace other drivers and specifically the fronts, then this becomes a huge issue... to put it simply; as soon as you start looking at the AmpPro then you should be using a DSP to properly route, manage and align the stereo signal.

sonicbooms said:

Got it and it's all sinking in.

I think it makes sense to start with the new subwoofer lol

Maybe I'll try replacing the factory speakers next and still keeping them on the alpine.

Then I might try running them on the new amp - there seems to be lots of people who are running part of their systems on the factory amp and part on the new amp with no DSP or regard for time alignment. Maybe they don't notice any issue, I don't know. I understand what you're saying and believe you, just wondering how perceptible it is.

I can also try disconnecting the center and pillars, just running fronts and rears and a sub.

Then finally if that all sucks, I can get a Helix 12 lol

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Correct - start with the Sub - you would be amazed at the number of people that I've consulted who had grand ideas of replacing everything but I convinced them to start with putting a "real" subwoofer in a properly aligned and designed enclosure in the vehicle and then never heard from them again till years later when they wish they could get back to that vehicle that they sold or traded... recollection is an evil companion.

The amp or drivers 1st is one of those things that is so subjective, I've seen it go both ways starting from different sides where some who swapped drivers were ecstatic and some had to move on to the amp in order to get satisfaction and then the same for the amp 1st, but if you put in a DSP/Amp combo on the OEM speakers then you can get to 95% of what you would have with better speakers but it takes practice, knowledge and ability to properly tune something. Keep in mind that the Manufacturer paid a team of engineers to tune the factory system and while tuning a system to the lowest common denominator is a means of reaching mediocrity it does mean that they spent some serious coinage and used some equipment that we can only dream about to design that system in the 1st place. Starting from scratch with a straight stereo signal can be an eye opening experience if you've never done it before...

Then there are "lots of people" who simply wanted their system to be louder and wouldn't know the difference between edge diffraction or comb filtering if you showed it to them and like you said, don't know or can't hear the difference. But I will say this, I've yet to see someone who has heard the "good stuff" who didn't dive head long into the rabbit hole.

So that brings us to your perception (which is all that matters) and that means that whether the gains are real or confirmation bias doesn't matter, if you are happy then everyone else can have a good day. So, start small, and take your time, do one thing, do that thing well and then give it time to sink in before jumping in to the deep end and realizing you forgot your life jacket.

This is simply my rule of thumb but anytime you have more than 10x the rating of the alternator then the 2nd battery becomes "suggested"...

Ex: 240A Alternator so anything over 2.4kW and mine is close to 4.5kW thus the dedicated battery.

Big NO on the battery charging...

You still run the 1/0 wire from the starter battery to the audio battery and they get connected in parallel so the alternator is charging both all the time. Mine has an isolator but that's overkill for running parallel batteries of the same type.

If you have the audio battery a few inches from your big mono amp then you can get away with a pretty small battery. Mine is the XS Power XP750 which is about the smallest one they make and the 750 is the rated Amp Maximum (which by the rule of thumb is 7.5kW even though they rate it for much less) draw.

Now, if you intend to run ignition off for hours at a time then obviously you'd want one much bigger. But even with mine idling at night with all the lights and the AC running there's no dimming (led interior lights) even at full boogie.

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"Ultra" or "Super" Capacitors work extremely well but the old Rockford Fosgate paper that suggested 1 Farad per kilowatt was overly optimistic because at that time getting a 500 Farad capacitor was unheard of... And it would be more accurate to say that they (stiffening capacitors) are more suited to large amplifiers unless you are looking to do a full on custom build with individual cells.

Advances in manufacturing and electrolytic design have made this 500 farad (and more) reachable now and the new rule of thumb is more like 8-10 WATTS per Farad so a 500 Farad Capacitor is good for 4-5kW. The reality is that it will do MUCH more than that but calculating actual ESR (equivalent series resistance) and possible change in charging rates for all the possible variations in installation and equipment means that overkill in capacity is much easier. The bad side is that they are extremely dangerous and have to be initially charged very carefully along with appropriate discharging and grounding methods anytime you do maintenance cause the short circuit potential is in the 20-25kVA range (equivalent to the service level for a large residential home.)

But for smaller (who would have thought that we'd be calling a 1.5kW amplifier small?) Installations that run AGM batteries with their enhanced ability to deliver transient amperage and recover with greatly increased recharge rates, the squeeze is not worth the juice. But if you are stuck with the old SLA (sealed lead acid) batteries from the past then a capacitor is definitely worth looking into...

Multiple batteries: The current trend of start stop designs is a perfect example of a smaller battery connected in parallel with the starter battery and adding a third battery in parallel with these two is fine. There are arguments and research being done that say this actually extends the life of all the batteries connected together. (Utility Scale electric substations use DC Power from huge battery banks that have from many tens to a hundred cells connected in series/parallel combinations with no problem.) And while there are situations where you need to "level" multiple battery installations when all the connected batteries are called upon to deliver massive amounts of power simultaneously, an installation like this where the bulk of the long duration current draw is handled by one battery (cold start) that is not really a concern.

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