Obviously after all the hype, demos and finally a release, Audiobus is one of the most influential apps put out in 2012 for iPad music making. There are plenty of in depth reviews, previews and demos out there already so I finally got to making my own piece with it and will let you know my impressions. First and foremost though, here it is:
This particular piece was almost entirely done on Audiobus with live recording into Harmonic Dog's MultiTrack DAW. The source synths for this piece included: Animoog, Sunrizer, Rebirth and the Korg iMS-20.
The only non-Audiobus pieces were the vocal effects which used Audiocopy/paste and were captured from freesound.org via the iPad GoodReader app and processed in Hokusai before pasting into MultiTrack DAW.
Audiobus allows iPad users to finally put together a sort of best-in-breed DAW. Rather than relying on sandboxed all-in-one solutions that are limited to one vendor, by providing live audio recording across apps, we can use any compliant synth, any compliant effects and any compliant target. Note the word "compliant"! This means that for apps to work with Audiobus, they need to update and include code to support the standard. The great news is that many apps have already done that. The not-so-great news is that not every app is there yet.
Already, tons of synth apps support recording their audio into target apps. On the target side, however, the choices are still a bit limited. I suspect it is harder to be a "target" than a source, so we will see this grow over time.
As you can see elsewhere in greater detail, audiobus supports "sources", "effects processors" and "targets" (apologies if I have the terms wrong). Many apps already exist in the "sources" and "effects processors", but for serious recording you need DAWs to support the target side.
I am very anxious to see Auria support, but that is going to take a few releases before it and Audiobus work well together. Since I'm impatient, I invested $10 in MultiTrack DAW which already supports Audiobus. I also bought "Loopy" which is a live looper app, but of the two, MultiTrack fits my workflow much better. Loopy is better suited to live performance but is by the authors of Audiobus, so its support is not surprising.
One of the biggest advantages of audiobus is that it allows you to live record audio from any source application - particularly those that do not have convenient or easy recording facilities on their own. In the piece above, I recorded Sunrizer and Animood directly into Multitrack DAW with Audiobus rather than rely on the flakey recorders in each app. This was really much easier than audio copy/paste.
In the sandboxed environment of the iPad (which is gradually becoming the norm on desktops as well), this may be the future for inter-application recording. We may see similar schemes eventually replace the VST and AU plugin architectures on desktop DAWs since sandboxing solves so many of the security concerns on desktops (but at a price of convenience).
I will be doing much more with Audiobus in the future and will let you know how it goes. As things stand right now, I think audiobus works well in conjunction with audio copy/paste. Things will only get better as time goes on.