Fixed: Skype FOR BUSINESS automatically adjusting microphone volume control

I got a shiny new HP laptop, and started having the echo problems in my conference calls again.

What the heck?

I discovered that Skype for Business also automatically adjusts the Mic, and it runs the gain too high causing echo.

These registry keys and a reboot fixed it.

reg add "HKLM\Software\Microsoft\RTC\DeviceSettings" /v "AnalogAGC" /t REG_DWORD /d "0"
reg add "HKLM\Software\Microsoft\RTC\DeviceSettings" /v "DigitalAGC" /t REG_DWORD /d "0"
reg add "HKLM\Software\Wow6432Node\Microsoft\RTC\DeviceSettings" /v "AnalogAGC" /t REG_DWORD /d "0"
reg add "HKLM\Software\Wow6432Node\Microsoft\RTC\DeviceSettings" /v "DigitalAGC" /t REG_DWORD /d "0"

Run those commands from an administrative command prompt to disable the AGC (Analog Gain control) for the RTC (Real Time Communications) API.  This API is documented here, but the registry keys are not.  The registry keys came from this Technet blog post in Japanese

I'm happy it is fixed.  Now I can be on conference calls without causing echo and having to dial in from my phone.

For the record, this has been raised on Skype For Business' User Voice site and currently has over 1600 upvotes.  Please take a moment and add your vote.