Steps:
1. Downloaded cm-10.1-20130426-NIGHTLY-i9100.zip and copied to internal SD. Verified MD5 checksum (9f62e5804c42acf46f43130132c5d6e2).
2. Reboot into CWM Recovery.
3. Created backup.
4. Flashed cm-10.1-20130426-NIGHTLY-i9100.zip
5. wipe cache partition.
6. advanced > Wipe Dalvik Cache.
7. Reboot.
Settings > Sound
