The RPI has one major problem with audio. The clocks coming from CPU can only output one frequency clock perfect (very close), resulting in major problems with audio files sampled at 44Khz (and multiple). Too much jitter on i2s clocks. So we invented the Kali but there is a second way.
The board will come pre-programed as a 2.1 output (but you can create your own custom design and load it the board and can access the xover frequency directly from linux (we made a small app).