Audio terminology is kind of a mess,which is one of the reasons why the world of audio can be so hard to learn and navigate.
Some people say “echo” and mean reverb. Some people say “echo” and mean delay. Some people say things like “aux cable,” whatever that means. Unfortunately, learning the technically correct definition doesn’t really help you understand, and it just turns you into an annoying word police nerd person.
I’ve spent years explaining this stuff to students, friends, colleagues, and all kinds of other people. I wanted to make a reference that actually helps you understand audio, so I wouldn’t have to keep explaining the definition of line level over and over.
This is a beta. I’m still building it, adding things, and figuring out the best way to present the information, but there’s plenty here to explore already. Poke around, follow the links, and see where you end up.