calibration: A2B was broken for tetrahedral mic, probably due to tests when starting work on the Octathingy, sigh

calibration/src/A2B_matrix.m

@@ -55,7 +55,7 @@ function [A2B pv max_err] = A2B_matrix(Y, X, v_z_factor)
     end
   else
     %% W X Y Z
-    A2B = [1 0 0 0; 0 1 0 0; 0 0 1 0; 0 0 0 1] / pv;
+    A2B = ([1 0 0 0; 0 1 0 0; 0 0 1 0; 0 0 0 1] \ pv)';
   end
 end