Enabling High Definition Audio (HDEF) on your Hackintosh can be accomplished a number of different ways. My personal preference is to modify DSDT.aml with hardware-specific information, and install a LegacyHDA.kext in /Extra/Extensions. You must replace all references of AZAL in your DSDT with HDEF, then insert code that references your specific ins and outs.
Alternately, a solution that works for many people is to use HDAEnabler.kext combined with a modified AppleHDA.kext. There are drawbacks to this solution, as each time Apple pushes an update, Apple's AppleHDA.kext is overwritten, and will have to be replaced in System/Library/Extensions.The most universal audio fix is VoodooHDA.kext- it is an enabler which at startup uses brute force to probe your system and get any kind of audio output. Most often it is not optimized, and can leave you with audio artifacts, stuttering, volume issues and popping sounds.
I added a new set of DSDT fixes to tonymacx86-DSDT-fixes.zip with instructions on how to enable the HDEF fix in DSDT.aml to use a LegacyHDA.kext. I also optimized each DSDT in the DSDT Database to include hardware-specific HDEF fixes. Good luck!
NOTE: Here are the currently recommended LegacyHDA.kexts for P55 motherboards. For use in combination with HDEF DSDT edits.
Legacy888bHDA.kext.zip
Legacy888HDA.kext.zip
Legacy889HDA.kext.zip
Legacy889aHDA.kext.zip