Recording acoustic grand piano with 2 mics

Is anybody else recording acoustic grand piano with 2 mics or setting up and using an aggregate device?

I purchased an Apogee MiC 96k that plugs into my iPad mini's lightning input. It records very nicely.

But I want to put this Apogee mic on one side of the piano and another mic (just a regular mic that plugs into the 3.5mm input) on the other side of the piano.

Hopefully to get a better balanced sound recording from the piano.

I've been told that it can be done by setting up an aggregate device. Then I could use the 3.5mm input with a regular mic. I was given instructions but they pertained to setting up on an iPhone, not my iPad.

I wish that plugging into the lightning input would not cancel the 3.5mm input, but it does. I have the iPad mini 4th generation and using the newest version of iOS, 9.0.2.

Thanks for any suggestions.

Don