This is just more of a comment than anything specific. On my 99 Civic, I have nothing fancy. I installed a Kenwood head unit ($95), replaced the speakers in the front and back with Kenwood 5.25" and 6x9s (around $150 total) and finally added a small power Kenwood subwoofer (8in slim sub, about $150). So...nothing fancy. So, when I first installed everything, I left all the settings in the stereo stock. And....it sounded ok. I messed with the fader a bit, tried a few equalizer settings, and....a little better, but always seemed a little muddy and a little two bright in the top end. I figured that this was just because I had such a cheap setup. I finally sat down in the car now that I am quarantined and have time to focus on this, and started reading about the default settings in the stereo. Then I went back to look at what are some common settings for the crossover. For example I saw that in my stereo the default is to passthrough all sounds, it's not even doing anything at all. Hmmm....so I go in, turn it on, set the tweeters x-over to 4Kz (after tinkering between 2.5k and 4k to see which sounded better), then changed the rear to filter at 80hz (after tinkering between 250 down to 80), and the sub is now at 80hz (played with it between 100 to 80) .

The change in the car was amazing! The soundstage now "sounds" correct, being in front of me and across the front of the car, the boominess and rattles I would get disappeared from the back speakers, the woofers now sound really clear. It's so far better you would have thought I stuck a whole new sound system in it.

Anyway, I just wanted to say that it's so important to get those "little" details right and I'm glad I finally took the time opportunity that this situation created. And it shows me that you don't have to spend a ton to enjoy some decent sound if you tune it right. Obviously this isn't competition level, but for my little car this is great.