I remember Concord. Wow.
I also remember putting a system together in the very late 70s using component drivers I bought from... [cough]... Radio Shack.
It sounded kinda good to my cheap assed high school ears. There were no car subs back then. Those drivers were meant for building home speakers. They survived OK in the car, though. I had a surround tear one winter but it didn't make any difference to the sound.