Realtek HD Audio left channel only fix for recording in Windows 7.
153For those who want the 30dB microphone boost using their onboard sound when they're using a discrete sound card like the Creative Soundblaster Titanium HD for playback but the 3.5mm mic jack on it isn't loud enough for ShadowPlay recording, Ventrilo, Mumble, Teamspeak, Skype, or Jitsi.
You MUST have the Realtek High Definition Audio Codecs (drivers) installed. As of this writing, R2.75 are available: http://www.realtek.com.tw/downloads/
You can disable the Realtek sound in Playback but leave "Mic in at rear panel (Pink)" enabled. You only get this wording when you check the box "Device advanced settings" in the official Realtek drivers in the upper-right of the window.
To fix the left channel only recording, you must enable either Noise Supression or Beam Forming. It's completely unintuitive and weird. I don't have an explanation for this, but you see the behavior right in the video.
Although the recording quality is noticeably inferior to the Titanium HD, it IS louder at the OS level as opposed to just being boosted by software such as Mumble or Ventrilo. Not all software has built-in microphone boosting.
If you know a way to boost microphone audio recording in Windows 7 with a Creative Soundblaster Titanium HD, X-Fi, or any of the later Creative cards, by all means let us know. People all across this planet would love to get OS-level microphone boosting with their Creative cards.
Original post on the overclock forums: http://www.overclock.net/t/1496574/soundblaster-titanium-hd-vs-realtek-alc889-microphone-recording
Edit: After a few trials in different chat rooms, I'd say that even though it's very quiet, the Titanium HD is the superior card to record audio with from a microphone -- at least between these two cards. Realtek ALC889 / Creative Soundblaster Titanium HD