car audio info websites please ???

so im looking for somewhere to learn more about car audio. Im not exactly new to the game , i have done a decent amount of research but there's so much more id like to know ive been to the reference websites listed on here and liked the info but there wasnt enough. Some where that i can find very detailed information , when i read some of the posts on this website some of the people are so knowledgeable and i want to know where the hell they learned all this stuff lol , Ive done some looking on this website and other forums and Google and cant realy find to much of what im looking for , maby i just dont know how to search lol .. thanks !