Convert multichannel raw file to wav

Hi, Jeremy, hi all:

I'm converting to wav format a raw file that comes from this:

 $ pacat --record -d alsa_input.usb-BEHRINGER_UMC404HD_192k-00.analog-surround-40 > dump.raw

because it's the result of a three-microphone live recording using my
four-channel Behringer audio interface.  I expect the result to be a
three-channel file: what will the right sox command be?  The following:

 $ sox -t raw -r 44100 -e signed-integer -L -b 16 -c 2 dump.raw output.wav

produces a two-channel file: please help.  Instead, if I record with:

 $ sox -t alsa hw:2,0 output.wav

I get a four-channel file.  But I'd prefer using pacat.  Please help.  Thanks.

Cheers, Jeremy

Rodolfo