What can I use for mixing/muxing/splitting/leveling audio inputs and outputs? I was hoping to find a single tool that could arrange, in any configuration, any audio inputs and outputs on a Mac.

A specific example follows.

Devices

a) Line In from XBOX 360 Audio Out
b) USB from Headset Microphone
c) Audio out from Skype App
d) USB to Headset Earphones
e) Audio in to Elgato Game Capture (Narration track)
f) Audio in to Skype App


MIX

1) a + b + c =&gt; d
2) b + c =&gt; e
3) b =&gt; f


Audio needs to be mixed at different levels. For example, the USB mic level for headset, narration, and Skype can all be different.

I have come close with Audio MIDI Setup, Soundflower, and several copies of LineIn. But I can't split and join audio easily and I can't save the configuration - it has to be painstakingly set up each time apps are relaunched. Rogue Amoeba's paid app Audio Hijack looked like a good candidate but I did not see how to send resulting audio to an application or to a virtual device that could be designated as input for an application.
Audio Hijack is great for recording. For routing/combining inputs, look at Rogue Amoeba's Loopback. Unlike Soundflower, it is a paid app -- easier to use, supported, and handles multiple routings/combinations (which can be saved).