The audio quality is degraded, sounding like it’s missing some low or high frequencies or sounds very low bit-rate.
TuneBlade captures system-wide audio using WASAPI Loopback APIs. Music applications can notify Windows that they are playing protected content such as DRM files; On receiving such information, Windows degrades the sound quality on the WASAPI Loopback to copy-protect the audio stream. Hence, TuneBlade captures degraded audio from the OS which gets transmitted over AirPlay.
We’ve found XBOX music application (Metro UI) on Windows 8 to degrade the quality on WASAPI loopback for all it’s audio. We haven’t seen other popular music application such as Spotify, iTunes, Amazon Music and several other web based players to cause the degradation. Although, it is possible that they may do so when playing certain files that require copy-protection.
Another cause is when the Windows audio engine cuts off certain frequencies (usually low frequencies) that the laptop speakers cannot handle.
Fortunately, the solution is quite easy. Install a kernel driver software which provides a virtual LineIn->LineOut digitally connected pair on the system, and then configure TuneBlade to capture audio through this pair.
There are a few software which can provide virtual Line-In -> LineOut connected pair. We recommend VB-Cable Driver (Donationware). Or, if you already own a license to Virtual Audio Cable (VAC) or any other commercial application, you can use that too.
For a step-by-step instructions, refer to the TuneBlade documentation on this topic here.