Fixed Mine (Realtek ALC1150) gigabyte z97 ud5, all i did was right click on multibeast for yosemite. select show package contents then open contents folder and in resources folder find (AppleHDA-1150.pkg) and run it. once installed reboot goto system preference and select SOUND and in the output menu select "internal speakers built in. This worked for me and should work for most Realtek ALC1150 motherboards and also other motherboard types by selecting the correct package. To keep sound working after waking from sleep i use the Reset AppleHDA app. ps might be worth posting this in the El Capitan BIG fix list, good luck!