To enable audio on a hackintosh there are three basic options.

• Use a patched version of AppleHDA.kext.
• Use VoodooHDA, which works for almost all motherboards but is unstable.
• Purchase a sound card that is natively compatible with OS X.

Patched AppleHDA Method

Premade Realtek HDA Patches

Realtek ALC885
Realtek ALC887
Realtek ALC888
Realtek ALC889
Realtek ALC892 Note: follow readme install guide. Kext will not be preserved upon update.
Realtek ALC898
Realtek ALC1150 Note: requires DSDT patch. Your DSDT must be placed in /EFI/EFI/CLOVER/ACPI/patched for use with Clover.
More AppleHDA patches can be found at Insanelymac and osx86.net.
It is also possible to patch AppleHDA for your audio chip yourself. This is an advanced topic. If you are interested, check out this guide.

Installing Patched AppleHDA

Download the Audio Kext Enabler kext.
Copy your patched HDA and Audio Enabler kext to /EFI/EFI/CLOVER/kexts/10.9
Navigate to /System/Library/Extensions backup and delete the AppleHDA.kext located there. Note: You may have to redo this step after an update.
If in the process you cause your computer to kernel panic, boot to safe mode (-x) and restore the original AppleHDA.kext.

Using VoodooHDA

VoodooHDA is compatible with more products but what it gains in compatibly it loses it reliability and quality. Most users are expected to have mixed results.
Download Link
To Install, copy the kext to EFI/EFI/CLOVER/kexts/10.9. Navigate to /System/Library/extensions. Backup and delete AppleHDA.kext and reboot.
Here is a list of fixes for common VoodooHDA problems.

Purchasing a USB/Firewire/PCI Sound Card

This is probably the most reliable option. I recommend that anyone working with audio or music production do this.
Any interface advertised as compatible with OS X should work. Just be sure that Firewire/USB3.0 are functioning if you get a card for them.
I use a Lexicon Alpha on my system and it worked completely OOB.