This seems like it should be a really easy one, but I'm having trouble finding a clear reference or explanation for it.
According to Wikipedia, line level has a peak around 0.5V, but I can't tell if that's GND to 0.5V, or -0.5V to 0.5V, or something else entirely. Which is it? (EDIT: Nevermind, it's now clear that it's the second case. Here's a scope capture linked from the Wikipedia page.)
The reason is that for switching ICs (mux, pot, etc), you need to have a V+..V- which exceeds the range of the analog signal, eg from MCP42XXX datasheet p15:
For linear operation, the analog input and output signals must be in the range of VSS to VDD for the potentiometer...
Since the line level audio goes below GND, I assume I need a charge pump or virtual ground arrangement to use an IC such as the MCP42XXX. Is this so? Which is the recommended approach?
Edit: I discovered the answer to the first part of my question, but the second part remains relevant.