To understand the fix, you must understand the hardware. The A1278 uses a specialized audio controller from (specifically the CS4206/4207), not a standard Realtek chip. Apple designed this chip to work seamlessly with macOS.
: Download the Boot Camp Support Software 5.1.5769 from Apple Support Apple Macbook Pro A1278 Audio Driver Windows 10
A: Install the "Realtek Audio Console" replacement app? No. Use Equalizer APO as mentioned above. The Cirrus chip has headroom. To understand the fix, you must understand the hardware
: Boot Camp Support Software for your specific macOS version. To understand the fix
