After one whole month of researching, I've found a solution to Instagram's major reduced audio quality problem! The culprit are the Baseband versions in GB27 & GB28!
Though I've fixed it by first upgrading to Cyanogenmod 10.2-20140330-NIGHTLY-d710, then flashed it with FL24, through ClockworkMod Recovery v220.127.116.11!
Note: I have a rooted Epic 4G Touch, through Virgin Mobile. Also I'm not responsible if your device gets bricked. If you don't know what you're doing, then I most definitely guarantee that you first research before actually doing any of the following below.
Requirements/Summary (Steps in order):
Step 1: Make sure that your Epic 4G Touch is rooted first!
Step 2: Download & install a recovery firmware. I used: ClockworkMod Recovery v18.104.22.168
Step 3: Upgrade to Cyanogenmod 10.2-20140330-NIGHTLY-d710
Step 4: Download FL24, the file's attached below the page.
Step 5: Flash FL24 through ClockworkMod's recovery mode.Note: This is risky! So yeah..
Reboot phone, then tada..enjoy!
Also note, GAPPS (aka..Google app store), is not installed with this version of CyanogenMod.. & you may encounter a MMS problem through this version of Cyanogenmod. Fix for the MMS is here: MMS Fix
problem can be fixed by researching through sources! Enjoy!