Expandore is one of the cheapest around. Those guys in SLS are more expensive. Higher overheads. But be warned the FX1 and FX7 has lots of short comings besides the audio. This is Sony's way of dealing the seperation between the Pro cams and the prosumer stuff.
From the VX2000/2100 with the PD150/170, the FX1 and Z1, now the FX7 and V1.