I bought my 6 Signature in May of 2018. It was one of the early ones that did not automatically come with Apple Car Play and Android Auto. I did get a free Car Play/Android Auto upgrade last October but the stupid dealer mechanic (the first Car Play/Android Auto upgrade he had done) had to replace the USB module in the center console, which also included the factory NAV SIM card, which he did not insert into the new module. The original USB module did not provide enough electrical power to power iPhones and run Apple Car Play at the same time. Since I used Waze as my main NAV app, it was not until a few weeks later that I noticed the factory NAV did not work and the SIM card was missing. The Mazda dealer refused to take responsibility for removing the SIM card, so I had to pay $55 to buy one from another Mazda dealer off of eBay. Never the less, I really like the Car Play interface. I use the Vox app to play mostly hi-res FLAC files.

I do not use the Bose Centerpoint processing. When Centerpoint is turned off the center channel is only used for phone calls. The center channel is a matching mid to the left and right dash speakers. My settings are as follows: Centerpoint off, Fader set all the way to the front, Balance center, Bass set to 0, and Treble set to +1.

The factory speakers are cheap and fairly generic. The door midbasses play all the way down to about 50 Hz with a factory hi-pass filter in the Bose amp to keep them from distorting. The midbasses, although being about 9” in diameter, are very thin and the cone does not have much movement (X-max), which limits their low frequency performance. The door midbasses and tweeters play off the same channels of the amp, like in a two way component set. The midbasses have no passive crossover and play all the way up to their physical limits while there is a generic crossover hi-passing the tweeter. All three dash mids gets their own independent amp channel. It seems the left and right dash mid is just there to fill in the midrange that the door midbass can’t play up to and the tweeter can’t play down to. It’s like the Bose engineers said “we have a large gap in the midrange just using the midbass and tweeter, lets just add another midrange to fill in the gap. I haven’t tested if there are active crossovers built into the Bose amp yet.

The rear door speakers are on their own independent amp channels while the mids in the rear deck are on one channel and are played in mono. If you fade the system all the way to the back, you will hear no bass and no treble. I estimate the rear doors are cut off around 500 Hz and below.

Overall the Bose system does sound ok and slightly better than other factory systems I have heard but nowhere near audiophile quality level.

There is a “Tuner and amp unit” located in the dash to the right side of the glovebox. PAC audio makes an adaptor that plugs into this unit that has RCA outputs, but it is not certified to be used with 2018-2019 6s. Coming out of this unit and going to the Bose amp are left and right front and rear audio signal wires and an “Audio Pilot” wire that should be similar to RCA cables. The Audio Pilot wire should carry the center channel and NAV sounds. I have not tested them yet but I suspect the signal wires are probably un-equalized full range stereo. I’m hoping any eq/active crossover work is done in the Bose amp and that the factory volume knob adjusts the volume in the tuner unit and not in the Bose amp. If so one could just tap into these signal wires and run them directly into the RCA inputs of a DSP and still be able to use the factory volume knob!

If I have to use the speaker outputs of the Bose amp to go to my DSP, I have a JL Audio Fix-82 that will “correct” the Bose eq to give me a flat signal.

In my system I plan on not touching the center or rear channels coming out of the amp. Since I am not using Centerpoint processing, the center channel is used only for phone calls. Since I have the audio faded all the way forward, only the rear deck mids play the warning beeps when I am backing up. I will either tap into the front left and right signal wires before the Bose amp (preferred) or run the front four (L/R doors and L/R dash) speaker channels into my JL Fix-82.

As far as speaker layout I am going to use I will start out with tweeters in the factory dash locations, mids in the kick panels, midbasses probably under the dash on the firewall, and subs in the trunk. The a-pillars have the side defroster vents in them and unless you are willing to get rid of them putting mids and tweeters on the a-pillars will require you to build them out from the a-pillar and blocking forward vision, which is something I don’t want to do. I did buy a spare set of a-pillars from my Mazda dealer (at $276 a set!) if I ever want to custom build mids and/or tweeters into them.

As far as speakers go, Morels have a really good reputation, but the overall sound will mostly come down to install and tuning. I don’t know what your budget is so I can’t really recommend certain speakers yet. I would not recommend using the factory door midbasses. I would replace them with a thin (under 2-3/4” mounting depth) 6-1/2” to 8” midbass. Metra makes a speaker adapter plate that will fit the 6: https://smile.amazon.com/Metra-82-75...ronics&sr=1-12

I would bypass the Bose amp on the front channels and run the signal to a DSP/amp combo like from a reputable company like Audio Control, JL Audio, Arc Audio, Zapco and other well respected brands. That will give you the best bang for the buck.

As far as install pics go, look on page 3 of this thread: https://www.diymobileaudio.com/forum...ld-thread.html

Although Jay's 6 is a 2016, the metal structure of the 6 under the panels has not changed.

Hope this helps the let me know if you need any more info!