XTerra 50 swing speed....Read a comment on the MXT forum that the M6 with the small coil in trashy areas works very well with a slow swing speed. My XT50 doesn't work very well with a slow swing speed, seems to lose depth. Since the M6 is a 14 KHz freq machine, I just wonder if the XT50 will work the same way with a small coil in the 18.75 freq as far as a slow swing speed goes? Thanks, John