862 Views 1 Reply Latest reply: Oct 6, 2006 1:11 PM by HangTime
Before you look for a book, I'd suggest doing some web searches. Drop the "AU" part (AU stands for Audio Units and is simply the 'type' of plug in that GB uses) and search for "band pass" and "parametric EQ", etc. You'll likely find more information then you could read in a life time.
For the "When/why", for the most part that is subjective. You use an effect when the song you're creating requires it, either as an effect to add a little flair to something, or as a way to make a recording sound better. Once you learn what an effect does (and BTW, playing with effects at their min and max settings can tell you a LOT about what they do), you let your ears tell you if and when to use one.