Sorry if I wasn't clear. The attached traces don't help very much. By "stack trace", I mean you use gdb's "backtrace" command to see what function was running when the crash occurred. If you have a core dump, the syntax is something like
 
gdb -q -n -ex bt -batch /usr/local/bin/sox coredumpfilename
 
If you can't get a core dump, you would use gdb to run sox, then when sox crashes, you would execute the "bt" or "backtrace" command. Something like:
 
dcook% gdb sox parameters...
gdb% run
.
.
.
SEGFAULT
gdb% backtrace