Sorry, I accidentally replied to Chris himself and forgot to "reply to all" . Here is a repost.
Hi Chris,
First of all, kudos to your book (Learning CoreAudio: A Hand on Guide...) which has served as my very first CoreAudio learning resource (and still one of the main references)!
In fact the examples I talked about include the Ch10_iOSPlayThrough example of your book where only one AU is used, no graph. I'm not sure if my copy is up to date though. I got the book and code in 2011.
The Xcode iOS example aurioTouch2, which does input play through, and waveform/spectrum/spectrogram visualization, also uses a single AU, no graph.
Hence my question. I do realize that my original question was a little rushed up. AUGraph is of course needed when multiple AUs are required to form a processing chain. My concern at hand is a specific case: I have really just one AU in a graph.
Thanks!