The short version:
The low sound volume problem appears to have been solved in kernel 3.10.16 (and 3.10.17).
The long version: After installing the 3.10.16 kernel, I noticed the low volume problem seemed to have returned. Just on a hunch I removed the file in /etc/modprobe.d/ (as described above), rebooted, and the sound was back to what passes as normal.
Thanks, again, to Mr. Volkerding and all of you for your help and suggestions.