1. Post TAU speaker wires. In your case is still post Bose AMP. All 4 door speaker wires.
2. No noticeable bass roll-off. I haven't read up on a LC7i
3. most people recommend using the rear speaker signal.

 

I agree that owners should go into audio settings and zero out all audio settings. Then adjust Bass first, then Treble, then fill it in with Mid adjustment. You can use Audacity on a computer to record the music sample then analyze on computer to make sure you have adequate dynamic range. It is amazing that once you do this and you focus more on remastered music marveling at the missing music on any decent audio system. Many artists produced great analogue records, e.g. Kate Bush, so remasters are not needed for these artists that control their music and make sure record companies make a quality audio product. Junk In Junk Out.

 

Unfortunately, most people are to some degree tone def and the road and vehicle noise cancel out most everything you just posted. It ok if parked and there is little outside the vehicle noise level.
You also did not account for air volume in the cabin area your response which greatly effects the end sound adjustments. If you tailor your listening adjustments to 1 occupant and then you get a single passenger and now everything you just set up is gone. And let's not forget that lets say Sirus XM broadcasting, every channel would technically need readjustment of your sound level, gains l and frequencies.
Sorry friend but quality of the sound equipment, speaker choices and location, amps and audio control matters more in the end when pleasing the individual. And flat lining the setting really does not work for the average listener..

And then there is the the real world or the db of life. It changes with road condition, weather, vehicle speed, and operating environment. That causes a true Audiophile to simply adjust to the best overall adjustment in the sound reproduction. For none audiophile or "Joe & Jane" average it usually means the typical "V" pattern on the equalization or tonal gains adjustments and sound forward or front speakers. ROLMAO.


We would build a custom audio system in a customer's ride and use pink noise to adjust the frequency curve for the best speaker location and sound reproduction possible in the cabin environment. Only later to have the customer return complain not enough highs or a flat bass only to see they went in and did their own adjustments that totally "fricked" up what music sound and was made to sound like and the best quality basically for their budget should sound like. LOL

As for Kate Bush, while I don't listen to her, I am mostly these days smooth Jazz, some long hair but heavy Metal and old Rock is rare, but I did play a couple of her songs in my Mazda, and I will say with the windows up engine off parked in the garage with the garage door close it was Chrystal clear and concert quality. But then I have a very well-built sound system in my Mazda.

 

In the 1990s and early 2000s a simple radio upgrade using existing speakers would make a big difference due to better amp. The penny pinching is everywhere though cars in the last 10 years in general have much better base audio. My father selling a certain cutting tool brand used to call on Bose when he was sent to Rochester NY. IIRR GM was the first to use the Bose system in cars. My fathers 1985 Buick Riviera had it which was a real revelation for a young kid.

 

Speaker upgrades....
Can anyone tell me what sound quality the vehicle owner is going for when the subwoofer will move the vehicle down the road without the engine running?

 

I hate to break the bad news but in the early 80 we were experimenting with Bose speakers in vehicles.
We built a custom stereo system for a friend in my shop which used BOSE speakers with powered by a Nacmuchi connected to the 4 12-volt deep cycle batteries and a converter in a Chevy S10 with a small utility shell. The utility shell was all paneled and insulated. It really sounded very nice and hit hard with the 4 15inch subs. LOL. But the system was bulky. Worked for the Pickup but was to big for any car. At least to have a reasonable build.
My own 1982 Camaro had 4 amps and 36 speakers (you could only physically see the sub in the rear and the 4 other door speakers. The remaining speakers were all behind custom panel that resembled a OE panel. at that time and could displace 110db without distortion. The system was fantastic for the time period when stereo challenges were just begining. .


Well not that I thump around but I do have 2, 12, in my trunk. However, to be clear although I could thump just as good (better) then the kid that booms his ricer or ghetto on wheels down the street my Mazda is so well insulated that even hitting hard you can barely hear the sound outside the car. And my licence plate does not rattle! LOL
As I have posted somewhere I am all for the best quality I can get for musical reproduction and currently my taste is primarily smooth Jaz with favorite instrument listening to the Sax.

 

Ha...those woofers are bit of an over kill for smooth jazz.
I actually played sax before it was cool and long before "Dark Side of the Moon".
I switched to guitars and now wish I'd had still kept up with the sax.
But if you're into sax those woofers work great for any Candy Dulfer music.

 

No actually not really. You are assuming that they thump (they can) but they complement (all the gains on the sub-woofer amp is at the lowest setting and the cut off is 24db at 250hz) the very low frequencies that my Focal subs in my 4 doors. Thos are set at the lowest gain as well and Low pass cutoff is 200hz @12db high pass 500hz@12db. Nataully I can go into the mid bass ,mids and all the tweeters frequencies, but I think you get the picture that this was not a slam together set up. I went through at least a couple dozen speakers and install to find the best match for the Mazda for sound quality. My Focal in the 4 doors are full sets of K2's. LOL

Thanks for the tip on Candy Duffer. I like it! I also really enjoy Acustic Alcomy, but more there older music.

2 sets of these went into each door
I should mention that I removed my complete interior and sound proofed the complete floor ,roof and all the doors.

 

I am more into the older stuff as well - Sonny Rollins and John Coltrane are probably my favorites on the sax. Acoustic Alchemy is good, but Wes Montgomery is the king of the guitar with Lee Ritenour running close. Miles Davis leads the trumpet, but Louis Armstrong is hard to beat on the more traditional jazz.

However, getting back to car stereo, my hearing has gotten to the point that I no longer see much purpose in spending a lot of money and effort on signifcantly improving it.

 

Sorry to read this. I know with me a full sound experience if it be music or movies is part of my enjoyment.

I would think that if I were to recommend the best upgrade that would drastically increase the full music experience with a factory sound system would be add sound deadening material to all the door cavities, rear hatch or trunk. There are area's but it get a little more less DIY friendly and if having it done costly.