Fixed the sound issue finally by using full sample plist and editing CPU frequency.
I am using 0.5.8 opencore
Drivers: Vboxhfs, Openruntime
Kexts required: Voodoohda (hdmi and analog audio works), Realtek8111, VirtualSMC, XLNCUSBFix, Lilu
Optional kexts: Whatevergreen (testing DRM currently not...