2020+ IOS/IOT BOSE & Fix86 Tips

DarkKnyte · 06-03-2022, 02:38 PM

I couldn't find an accurate wiring diagram for my stereo without paying a ridiculous fee, and no one here that had one was willing to share it with me

, so I made one myself for everyone to use.

The wiring colors are pretty similar to earlier Camaros, but things are moved around in the actual connector, and they swapped the polarity of the wire colors for the right dash tweeter for some reason. I checked 3 times, because it didn't make sense, but the wires are swapped in the connector vs diagrams that can be found for earlier Camaros. I've also included a table on which outputs need to go to which inputs on a Fix 82/86. Forgive the smudging, this scan is from the actual diagram I worked off of while physically building out all the wiring for my stereo.

A word about LLJ Customs: Based on advice given here I purchased a loopback harness from LLJ customs to make these connections without cutting into the factory wiring. Having trusted that LLJ did the job right, it took me many many hours across 2 weeks until I decided the problem might be the harness and not my equipment. After cutting open the harness and examining it, I discovered that the harness was built very incorrectly with some really obvious mistakes (mismatched wire colors -- grey to green instead of green to green & grey to grey) and nothing worked the way it was supposed to when I hooked it up. Nothing. I'm still pissed about all the time I wasted dicking around with the FIX86 wondering why nothing was working correctly. I had to entirely cut the harness open to fix all the problems which made the all of their nice finish work useless. The harness was missing any connections for the tweeters & subs entirely. I even paid LLJ extra for the tweeter connections. The tweeter wires he included were threaded completely incorrectly through the harness for loopback and not even hooked up to anything! WTF dude? I had rebuild it properly with the tweeter connections looped back and then make four completely new runs for subs (rear deck speakers) to loopback. The terminals I paid extra for him to attach were hollow junk that pulled off with the most minor strain. LLJ is absolutely unresponsive to any kind of communications. He took many weeks to ship it (only shipping after I complained 5 weeks after ordering it that I wanted a tracking number), and then just ignored any of my emails when I complained about all the mistakes they made building the harness. It was a waste of a lot of time and money. 0/10 I do not recommend purchasing a harness from LLJ Customs. Just find the connectors or a cheaper harness from someone else because you are going to have to rebuild it yourself anyway if you buy it from LLJ. Not worth the expense.

The BOSE head unit sends a tremendous amount of bass energy to the speakers. I'd guess the speakers they built are not very responsive except in mid range frequencies, so they compensated for that by just pumping a lot more power into the high and low ranges. Normal speakers when hooked up to the BOSE amp sound like garbage because of this. More importantly, when you run the calibration for the Fix 86, it will detune the bass so much to create a flat signal that after the calibration it will sound like all the bass is missing. The highs sound ok when corrected, so I did not do anything special about that, but there was definitely a problem with the bass.

After spending a lot of time doing calibrations over and over again to find the problem, I took a look at the manual which gave me an idea. The Fix86 manual says you need to zero out your EQs for calibration, and while I imagine this works for most factory stereos, it sounds like trash on our cars. However, there is very simple fix. When calibrating the Fix86, set the bass EQ on your headunit to it's minimum level (-12, I think). Run the calibration, then reset the bass EQ to zero. The sound will be much, much better after calibration, even without a Twk 88 it sounded pretty good.

It's also important to realize that the BOSE headunit really, really splits up the frequencies in different areas of the car. You will need to use all 8 factory outputs to the Fix86, ignoring the center (more on that later). If you skip any of the 8 speakers, the Fix86 will not calibrate correctly and errors out (incomplete spectrum). Even if you do manage to get it to pass calibration, it will still sound bad like part of the audio range is missing. There are so many traps and gotchas when using this unit, I think I understand why it has a bad reputation for our cars. I really doubt a lot of installers put in the work to figure out the problems and do what needs to be done to make it work correctly. Following the above instructions, it actually sounds really good.

The center channel, door chimes, and turn signal clicks remain a pain points. There are only two signal processors that I am aware of that can handle more than 8 inputs, both are made by Helix and cost an arm and a leg. Without that, the center channel remains factory. Though I did not do this, my suggestion would be to put a 2 ohm resistor in series with the center to quiet it down without killing it entirely. Be sure to choose one that is rated for enough power handling, probably 20-25w is a safe choice. The major consequence of doing nothing is that you cannot properly time align the rest of the system because you can hear the audio coming from the center earlier than everything else. It's a miracle that the Fix86/Twk88 work so quickly that there is no perceptible delay as it is. The center speaker also sounds somewhat mushy in comparison to the Hertz & Kenwood speakers I chose for the front. You might think you can just turn the gain up on the rest of the speakers, but that quickly proves impossible as the 800hz chime you cannot make any quieter due to factory restriction will blow out your ear drums every time you open the door with the car running. Gains have to be kept very low in order to keep the factory chimes and dings at a manageable level. This means the center will almost always be audible in your system.

The included photos below show the diagram I made as well as an uncorrected audio spectrum measurement from the factory BOSE system into the Fix86. It's pretty apparent that the front speaker's bass (blue curves) get way more energy around 50hz than everything else. The highs are clipped so bad you can't even see the peak. The rear speakers are more reasonable, but all the low frequencies go to the deck speakers in blue, while the mids and highs go to the speakers in the rear seats.

DarkKnyte · 06-03-2022, 02:39 PM

To get the most out of the TWK-88, you will need a purpose built measurement microphone, with calibration to measure the sound output from your various speakers and make the appropriate adjustments. I used the Dayton Audio UMM-6 usb microphone. Each mic has a calibration file you can download directly from Dayton using your mic's serial and then put into your RTA program. I also purchased 15 foot USB cable so I could be outside the car while tuning certain things like gains on the AMPs. It helps to not have to get in an out of the car when calibrating gains.

I used a macbook pro as my platform to run the JL audio TUN 4 software. If you have a more recent MBP, you'll need to get USB B -> USB C data cables for both the TWK88 & Mic. Not all of the really long ones work correctly, so check the reviews. JL just released an update a few weeks ago that includes RTA functionality in TUN 4 so you can adjust your EQs and see real time feedback on the sound in a single pane. If you aren't used to tuning the TWK 88, I really recommend watching their training video on it. It's kinda dry, but you do learn a lot of useful information.

Another really, really important aspect of audio tuning, is understanding that a flat speaker response looks good on paper, but doesn't always sound good in practice. Each of us has unique hearing. I have seen an audiologist to have my hearing tested, and in my case I have a slight deficit of mid range tones in my left ear. Accounting for that when EQing my left front door speaker does make music sound better to me. There is no one perfect EQ, and in fact that is what the EQ knob is for. You can make different presets for different kinds of music and switch between them as desired.

Unbelievably there is absolutely nothing in either the Fix86 or Twk 88 manuals about integration between the two devices. However, based on advice from JL audio technical support, if you are using the Fix 86, you should only use the front and rear RCA connections when going to the TWK 88. If using the Fix82, this will not affect you.

One of the main selling points of the TWK is that it allows you to run what's called an 'active crossover network'. Basically, the TWK handles all of the crossover duties that you might normally relegate to passive electrical crossovers. If you have a TWK you do not need to include any passive crossovers (either inline capacitors or full second order crossovers) in your speaker design. There is no need, and it will not improve your sound at all -- particularly the inline capacitors.

As well, it's important to either disable, set to ;full range' or set your the crossovers on your AMP to their most permissible bandpass. The TWK is very, very good at sending only the correct frequencies based on your specifications, and it's does not sound good at all when you double up passive crossovers 'just to be safe'. As long as the the TWK is configured correctly, it will literally not send sounds to speakers where they do not belong.

When you create your crossover network, which is specifying the upper and lower pass frequencies, and slope, this will create a curve in Tun 4 that you can use to benchmark your speaker performance against when playing Pink noise. Pink noise is the sound you will need to generate through your stereo and amps when calibrating your EQs. If you are using JL audio's ridiculously expensive audio measurement tool MAX, you can generate the pink noise from that, but as I don't have ~$3,000 to lay down, I used a noise generating app on IOS literally called 'noise gen'. You can also use either test tracks on apple music or a different frequency generator to generate specific frequencies so you can verify your crossovers are set correctly per speaker.

The TUN 4 software does include a difficult to use, but powerful auto EQ feature that will do it's best to flatten your speaker response to the curve created by your crossover specifications using the 10 available parametric EQs. Explaining how the EQ works, and what you need to do with it is well beyond the scope of this forum post, and is itself a really complicated topic. It is however covered in detail in the JL training videos (there are several). I will say that the EQ settings it came up with did a wonderful job flattening the response without any extra work on my part, and I could verify that live using the mic. That said, I did make some changes afterwards because I felt that the bass response wasn't where I wanted it to sound, even though it matched the curve very well.

I did run into a problem with the number of TWK outputs (8) vs the number of amp channels I needed to drive (9). My compromise was to use RCA splitters to drive both the rear deck and subwoofer from the same 2 outputs on the TWK. I then used the crossovers built in to the AMP to put reasonable limits on the speakers so the deck speakers don't get blown by the bass, and subs don't get distorted by highs. The EQ settings you make do apply to both sets of speakers, but there is only a relatively small area of the frequency range between 120 & 80 where it actually applies to both speakers. The rest of the response can be well controlled with manual EQing in TUN. You will not be able to time align the rear speakers with this compromise, but because of the center channel that isn't managed by the TWK at all, this doesn't really matter. You will always hear the center first, and there is little that can be done about that unless you want to disconnect it or run 10 amplifier channels and run the wiring for it. Even then the TWK still only has 8 outputs and isn't really designed to build a center channel. Though I think it can be done using settings in the TWK to mimic a 'passive center' circuit if you want to forgo dedicated rear deck or rear seat speakers, or entirely skip them to use the channels for the center and sub. I did not go this route, but I did research it.

If I had to design another system for a Camaro, I would have went with a 10 or 12 channel Helix DSP, and figure out how to fit 10 channels of Amplifier in that tiny well inside the trunk. Not because I'm unhappy with the sound, but because I think doing the time alignment and having a real center would be nice. It also would have cost about 4 times what I paid for the Fix 86/Twk 88 and 2 amps I purchased.

DarkKnyte · 06-03-2022, 02:41 PM

Equipment Selection:

Please don't consider my selection of equipment as an indication of anything other than this is what fit my budget, I believed sounded good, and in a couple cases, design compromises to fit the available space and power budget.

I expect that everyone has sometimes very passionate views of what equipment they believe creates the best 'sound', and my way of doing it is not more or less valid than anyone else's. I will say that for the most part, I'm very happy with my choices. Everything sounds amazing, and excepting that I need to resolve some heat issues by insulating my trunk floor, I'm really happy with my work and choice of equipment. No 'raygrets' as it were.

Design philosophy: I don't need a stereo for everyone else to hear. Honestly hate that people play their music so loud out of their cars. I want a system that sounds good, has enough power to hear it clearly with the windows down without cooking the amps, and has some base kick to it without rattling the trunk. I do not want to sound insulate the car, I like the road and exhaust noise and consider that part of the experience. It's a Camaro not a Lexus. My target system designed around 4 ohm equipment, and the amps will need to deliver enough power at that impedance to meet the above requirement.

Interface: JL Audio fix86. I desperately wanted a NavTV Zen GM-AVB. I bought the last one on amazon, which was marked incorrectly and was actually for a Mercedes. Nobody wanted to sell their's used, and the manufacturer kept saying "two weeks" for a year. It's not available, so I moved on. I'm not disappointed. The Zen experiences problems I don't have and my system sounds great with the Fix using the process I described in the first post.

Amps:

Rear/Main amp: JP95 5 channel, 1500w (200x4 + 700 x1) RMS, Class D I bought this particular amp before anything else, based on appearance alone. Review here. The red amp looks incredible in the back of my wild cherry car, and really stands out compared to almost universally dull black/grey equipment from other manufacturers. Has way, way more power than I need, good sound quality, excellent build quality and IMHO is really a standout show piece among competing amps. I think eventually, I'd like to cut my trunk deck cover to display this, it just looks phenomenal. This amp is driving my subwoofer, as well as my rear mid-bass and rear seat full range channels.

Front amp: I tried bridging my speakers as front and rear to only use 4 amp channels. It became complicated with crossovers, sounded bad, and just felt like too much of a compromise. Ultimately This is why I went with the TWK 88 and a second amp. I wanted better control over the sound and needed independent amplification channels for each speaker for this to work. The fronts do not use a ton of power, so I was able to pick a physically smaller amp. This was really important because I was out of room. In order to integrate this amp, I had to relocate the fuse box & magnetic ride controller to the passenger wheel well. Without it, there just wasn't room for everything.

A lot of forum discussions on audio quality and amp class/design will say amp class doesn't matter, but my own experience has taught me different. The class A/B amps that I have used have a very distinct and 'warmer' sound that they impart to music vs the class D amps I have. The class D amps sound great for dialog clarity & bass, they are lighter and use less power than A/B. The music I listen to however has a quality that just sounds better with the distortion harmonics from A/B amps. Even better, there are two particular, rare classes of amps that use an A/B audio output stage, but also combine a power saving design that varies the power usage of the amp to match what is required by the music. These are called classes G & H. Classes G & H amps have multiple or variable power supplies that only ramp up when needed, and so stay cooler and use much, much less power compared to a typical class A/B amp with a single power stage. They are very hard to find, and generally a bit more expensive.

I found one such amp made by JBL, the Club A754. There were no reviews of the actual amp sound that I could find, except one in Russian maybe. I translated the words, but it was kinda useless. There were a bunch of returns on Amazon which is not a good look, but because of that I was able to get an Amazon warehouse deal which made it really cheap @ <$200. That's actually an amazing deal.

Compared to the JP95, it's not really a looker. It's super basic gunmetal grey, with a removable cover and bezel that hide the gain and crossover controls on the top the amp, which I do appreciate. I cannot adjust the JP95 at all with the amp installed. I have to pull the entire amp rack out to access the gain/CO knobs.

After some time with the amp I don't get why anyone returned it. I sounds incredible, and in fact is what drives the main 'sound quality' part of my system. The amp is possibly under rated for power. Even with the gains turned literally as far down as they go, I still have to turn down the speaker levels in the TWK88 to make the door chimes tolerable. It's that powerful. The door speakers I got are sensitive @ 93.5 dB, so that probably contributes to it. That said, if it turn the gains up even half way, it make more sound at 50% volume on my headunit than I can physically tolerate sitting in the car. I'm sure it'll easily blow the factory speakers if you aren't careful. I do recommend this amp if you are looking for anything with 4 channels to drive tweeters, 6.5", or 6"x9" speakers. I do not expect this would drive a subwoofer with enough power, and is not intended to do so. The version of this amp that does have a subwoofer channel is class D and so does not have the audio qualities I was looking for from the A/B. It doesn't dim the lights, or indeed seem to make any serious impact on the electrical system of the car on it's own. It uses a 60amp fuse from the battery and has 2x 30amp fuses built in. It stays generally cooler than my class D.

DSP: TWK88. I needed a processor that would give me enough channels to drive each speaker in the system and enough configurability to make it sound good. This uses the same TUN software as the Fix86, and fit the bill nicely. I have a whole section on it in the previous post.

Speakers:

Tweeters: Kenwood Exelon KFC-X2C. These were recommended to me by my sales rep at Crutchfield as a good match to my door speakers, and because they fit in the factory locations without any modification. They are pretty nice, and sound clear up to about 10khz. Above 10khz, they lose responsiveness, but that can be compensated for in the TWK 88. It doesn't much matter because for me, loud distinct sounds above about 10khz trigger my tinnitus and in general hurt my ears which are really sensitive in that range. This is a really good example of why you should get your own hearing tested and figure out what works best for you. Little 1" tweeters instead of these 2.75" ones that mostly push volume in the 5-20khz range are wasted IMHO in a vehicle with a lot of noise anyway. Unless you are listening to orchestral music, symbol crashes and snares are mostly what go into that range and they sound great on the 2.75" speakers.

Front Doors: Hertz Cento CX 690. After using Crutchfield's really, really cool speaker comparison tool, I chose these because they sounded so damned clear compared to literally everything else more or less expensive. Yes, I choose full range speakers for the door, despite forum complaints about "muh sound stage" & "muh imaging". The windshields in these cars have a very tight angle, and it does have an impact on how the tweeters sound crammed back in the dash like that with a probably 50 or 60* angle on the glass above it. Again, I don't personally feel like I need to listening to music as if I'm at the front row of a concert when I'm in the car, with the windows down, going 75MPH, in sport mode with the NPP exhaust. I wanted to be able to hear the instruments. Where it seems like it they are overpowering the tweeters, the TWK is able to compensate and drop the levels on the higher frequencies so it's audible without being overpowering. Because they are 3 way speakers, they are also able to fill in the high-highs that are quieter from the dash. They aren't pointed right at you either, so the highs don't make your ears bleed. I do love these speakers.

Rear speakers:

I haven't actually installed these yet. Installing the rear speakers is a chore because you have to disassemble the entire rear interior to get to any of them. It's ridiculous. Not looking forward to it. That said, I have a set of older, but better made Infinity Kappa 6.5" that were installed, but never used in a project car that I plan to move to my Camaro. In that same project vehicle, I also have a set of Infinity Reference 9623i's that were also purchased a long time ago, installed, but never used. These will eventually be my deck speakers.

Subwoofer:

The last, but not least I settled pretty quickly on a Stealth box from JL Audio. These things were hard to find in stock last year. Due to covid, JL had manufacturing problems and they just weren't in stock anywhere. Fortunately, just as I was shopping, I found a member here who wanted to sell his. I snapped it up right away. Except for some scuffs in the carpeting and small dent in the grill, it was in great condition. Missing some mounting hardware I had to make by hand as well, because I guess his installer thought it was easier to drill an extra hole in the box rather than use the bracket made by JL specifically for installation in this vehicle. I ended up fiber glassing the extra hole, then cut and welded together a new bracket out of steel and carriage bolt based on measurements from JL's tech support.

I love the factory look, and the sound is amazing. The 12w3v2-4 kicks really f'ing hard. It's an excellent match to the output of the JP95. At 4 ohms, the JP95 can push 485 watts. I don't even have the gain turned up anywhere near that. I have it in balance with the system and you will feel toms and bass drums in your chest through the back of the seat when they kick. More modern pop music that includes synthesized bass music also sounds incredibly full with this thing in the car. Having come from an 8" factory sub in my Jeep, this 12" is just next-level. I honestly can't believe people feel like they need two of these or twice as much power. It bumps.

Installation gear:
People have mixed opinions about Crutchfield, but I do find they are a good resource for making things easier. I purchased my front speakers from them, and they forgot to include the brackets and wiring harness with my order. You will need adapters to mount aftermarket speakers. The installation brackets are built into the factory speaker brackets, and unless you want to hand cut adapters out of acrylic, just get the adapters. Crutchfield sent me mine, along with wiring harness adapters for the doors for free. I build my own harness adapters for the tweeters, but if I were doing it again, I'd definitely get the adapters for the tweeters too. I used NVX silicone rubber guards to protect the door speakers from water infiltration from the door. They work somewhat, but I did notice some water drops inside the liner laying against the speaker basket after washing bird shit off the door while working on the speaker install. Not sure how to feel about that, but I left the liners in place as it's better with than without out it. They were difficult to fit into the Metra adapters, but with some persuasion fit in there. I used the included open cell foam deadeners in the doors directly behind the speakers as much as I could with the reinforcement welded into the door panel there.

Installation notes:

The tweeters were a bear to do. The windshield pillar trims absolutely did not just pull out like the videos of anyone else show. I guess the upper retention clips were manufactured poorly, but instead of pulling out of the metal like every other panel retention clip, these ripped the damn plastic right off the trim piece! Ruined the trim pieces. After that you have to detach the microphone connectors and then carefully pry the clips for the elastic safety clips down and towards the trim piece to get them off. Then, you should be able to lift the trim out of the way. Afterwards I tried to glue the trim retention pieces back together, but the plastic is TPO with something like 6% wax mold release built into the plastic formula, and requires $60 specialty 3M epoxy for repairs. No other kind of glue I had, including cyanoacrylate (crazy glue) and regular epoxy would stick. The replacement trim, new is about $75 for both pieces, and the passenger side was out of stock. The car was new and I did not want junk yard parts from an older car in there, nor did I want to pay $60 for epoxy so I pulled the clips out of the pillars, rebent them to grab on to whatever remaining plastic they could find and reattached them. Thankfully, this time, they stayed. I do not expect that I will be able to reattach them again if I never need to pull them off a second time.

Every door panel has plastic clips that break. These panels have two types of clips that break. GM is so amazing sometimes, right? Even better, GM wants $5 PER clip. PER clip! Can you believe that bullshit? Talk about inventing a problem and selling the solution. Some enterprising forum members found the clips from a manufacturer for about $1.25/clip I think? Thank you, but seriously no thanks. These are molded for pennies and sold for dollars. It's clearly rip off, don't support either them. I could probably print them on my 3D printer for $0.05/ea. Instead I got my clips from Amazon for ~$0.50ea, and that was probably still too much money. They are, as far as I can tell identical to the factory grey clips. The yellow clips are a bit different, but I found that replacing the yellow clips that break with the grey ones had zero negative side effects. My door panel is tight to the metal, and I didn't have to pay rip off prices for cheap plastic. My driver's side door came off and went back on without breaking a single clip. My passenger side broke 4 clips on the way off, and 3 clips going back on, which required me to pull it back off and broke 2 more flipping clips. Glad I got the 30 pack.

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That's it for now. I'll probably update this thread with pictures and more information when I get more time to work on the car, but for now, I hope this forum post helps anyone working on their own car.

SomeGeoffGuy · 06-04-2022, 09:43 AM

I wonder if one of our vendors who can handle programming can do anything about the chimes? Hmmmm..... @GTPprix maybe?

-Geoff

keep_hope_alive · 06-08-2022, 02:57 PM

I did download all of the schematics for the radios (Bose and non) as well as interior removal instructions (about 100 documents). If anyone wants to PM me, I can share them.

keep_hope_alive · 06-08-2022, 03:42 PM

Nice work on this post. Great detail and good information.

I specifically avoided the Bose system in what I've ordered to save some of the hassle. You'd like to just steal the signal before the amp (which may eliminate chimes) but then you lose factory volume control and have to deal with the DSP volume control instead. Annoying but fairly typical for SQ builds that I see (IASCA SQ judge but not too active lately).

If chimes come through the door speakers, do BT calls also come through the door speakers? What signals come out of the center that do not exist in any other channels? Simply put, can you just disconnect that center speaker and ignore the signal to maintain the soundstage and tonality? I assume you've already experimented with just disconnecting that center to see what's left. It appears that the center signal is generated within the amp and doesn't come from the head unit.

One idea to incorporate the center signal is to omit the rear signals. We don't really care about rears anyway in an SQ system and with some DSP you can regain a fader with control knobs.

Another idea is to run an AC LC8i to sum the fronts before bringing channels into the DSP, this gets you two extra inputs by doing a pre-sum and only adds $250 to the setup. I don't like extra noise sources but it's one way to do it.

Another idea is just run a few JL VXi amplifiers then you can use the DSP and mixing/routing within the amps and use preouts to provide additional signal summing. Since you can run 5 amps with a hub, you can have up to 40 individual channels (with five 8 channel amps) tuned from a single USB cable.

DarkKnyte · 06-08-2022, 07:13 PM

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