Electronics... my findings

//Hopefully it's fine to post this here and not in CH//
So for the first time ever, I decided I'd do some real messing around with electronics - primarily a set of passive speakers and some signal amps. I dismantled an old battery powered iPhone dock with speakers that I probably got for $10 and took out the tweeters and amp. I've also got an old stereo system with speakers wire outputs that I'm testing with.
I'm mostly looking to see if someone with experience can corroborate what I found after about and hour and a half gumming around with this stuff:

1) A decent amplifier can push cheaper speakers REALLY far; I hooked the old tweeters from the phone dock to the stereo and could get them WAY louder than I've ever heard them, without ANY distortion (although being so small, shallow and cheap quality, they're super bright and tinny-sounding)
2) A crappy amplifier sounds bad even on GOOD speakers; I managed to run a signal directly from my audio interface THROUGH the amp from the phone dock and then into the speakers from the stereo. Audio quality was horrendous (although I think with proper, solid connections set up and soldered it could actually be made to sound a bit better, so this could be slightly biased by the fact that I only touched the wires to the different contact points. In addition, some part of the circuit introduces a high pass filter so no lows came through at all.)
3) All speakers need either internal or external amplification/power?; I hooked one of the stereo speakers to a 1/4" cable running directly into an output of on audio interface, but can't really get a particularly high level of volume, nothing close to my powered monitors or what I can get when the speakers are attached to the stereo.


This is all super-interesting! It makes me want to get into doing some real electrical stuff for fun. I'm wide open to tips and thoughts, esp. stuff regarding amplifiers and tweeters/woofers and whatnot. I can definitely see why building speaker boxes and stuff is a real hobby for some people.