2000 audio upgrade
 

I've never messed with car audio. Decided to try revamping my sound system. I believe I have the m490. There's an amp in the frunk, rear speakers, door speakers, dash speakers. No Bose. I'm having an issue with overall volume, the rear speakers aren't working at all, and there's distortion at max volume. Car already has a Kenwood head unit. No idea what horrors await behind it with wiring.

Parts ordered so far

Power acoustik single din car play/Android Auto https://www.walmart.com/ip/5055269224?sid=d0fa6bf7-d565-450f-89e7-f8cf7e102cff

Kicker ksc40 to replace dash speakers (crutchfield inxluses a pnp harness it looks like) https://www.crutchfield.com/p_20651KSC40/Kicker-KSC40.html?tp=105

Metra 70-1787 harness (also comes with crutchfield diagram and support which I'll need since I don't know what I'm doing)

From what I gathered searching here, the rear speakers are in series and powered off the head unit not the amp. My guess is someone didn't wire them when they installed the Kenwood head unit. But I suppose it's equally possible a driver is bad so the series isn't working. I'm hoping the crutchfield documents help me isolate the issue.

Suggestions for door speakers are welcome too. I know the amp crossover only sends lows to them. Most things I'm seeing are 4 ohm so I'm worried they won't be loud enough.

The rear speakers I'm also not sure about. Are they 2 ohm wired in series stock?

Are you running stock amp? the crossover makes it a pain. Honestly, I regret messing with speakers on my car - the surrounds were in better shape than i thought, and honestly sounded good enough. Swapping to the kickers will make them quieter (because they are lower db sensitivity than the factory speakers). If you are going to replace speakers, might as well get a 6 channel amp. I put a 4 channel amp in up front, and the rear speakers running off the head unit are severely underdriven. debating a 6 channel amp for a future upgrade.

Let me see if I can be of assistance, as I just went thru the same exercise:

My car;
2002 Base
Stock amp
Replacement HU
Rear speakers put in by me running off the HU
Door Speakers - Stock (2ohm)
Dash speakers - Kicker CSC 4" (4ohm)

Disclaimer: I am no audiophile by any strech of the imagination. I wanted/did upgrade to get a little bit more volume.

I installed HU (generic amazon Android 2din) and rear speakers a while back. HU is "ok"
Rear speakers (I ran one on each side (not 2 on each side) 4ohm 3.5" speakers, direct wired to HU.

Result: Worthless to rears, barely audible, just no good. Disconnected them.
Lived with it for a while. Decided I probably need an amp to replace stock, but did not want to spend a ton (or 1/2 ton) of $, just wanted something that was unobtrusive, cheap, and I could return to stock.

Got super-cheap 4 ch amp on Amazon (Boss Riot r1004 - $50), and wiring install kit ~$15
Decided (since amp is not strong at all, that i could run off factory speaker wires and save some time (plus, the speaker wire in install kit was not much (or at all) more robust.

Result: louder, yes, but ton of Alternator whine.
Checked with my installer (ChatGPT), and suggested running dash speakers and door speakers on separate channels, and high level filter the dash speakers. They suggested using Y cables to split input to amp from HU to 4 connectors. Also suggested filter for Alternator noise.

FIndings: Boss amp did not have HlF function, and adding more hardware to $50 amp seemed ridiculous, so I looked for next best thing, 4 ch amp with crossover filters.
Got another cheap amp (Taramps TS400 x 4 ~$75), and the y cables (~$7)
Result: RESULT!! Better-fuller sou-nd for dash and door, louder, cleaner, NO Alternator whine/buzz!
Just set the high pass filter on ch 1/2 (dash) and left full on door speakers.

Smaller amp fits on stock amp bracket, which the boss didn't

Hope this helps!!

This is a super nice write up, thanks for sharing! Out of interest, did you get an adapter for the amp side that connects the stock car connector to the new amp?

Thanks! glad to be of help. no, I did not use an adaptor (I was going super-budget0, tried some tap-it's, but that did not work well. Access is super tight. i ended up just cutting the speaker cables from the harness (the outbounds)..