/usr/src/linux-headers-3.13.0-61-lowlatency/sound is in linux-headers-3.13.0-61-lowlatency 3.13.0-61.100.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/src/linux-headers-3.13.0-61-lowlatency/../linux-headers-3.13.0-61/sound