I rarely have free time to work on my car lately, so progress on anything has been really slow. Today I thought I would finish installing wire loom over the speaker cables in the visible portion of the trunk and wrap up the manual portion of the sound system tuning. Well, I did both. Then I noticed the right rear speaker wasn't outputting any sound. I checked the wiring at the amp and the speaker terminals, then swapped the left and right rear speakers. Now there was no sound from the left rear speaker.
One of my old Pioneer TS-A6857 speakers is dead. Well, it was a cheap factory replacement grade coaxial anyway, only rated up to 50W RMS. I don't remember what I paid for them 15+ years ago, but it definitely wasn't much. I'll be getting a replacement pair that's a better match for my amp. It makes no sense to get the Alpine R-S68 again like I did for the front because I don't need pivoting tweeters in the rear, and I'm applying a -6 dB level adjustment on the head unit for the rear channels to enhance the front soundstage.
Since I want something with a true 6x8" frame instead of a 5x7"/6x8" combo, I'm looking Kenwood's way now. I won't be working on anything for at least another week though since I'll be on vacation. I'll probably order the speakers toward the end of the trip though.