Windows Media Player Dolby Surround 5.1 II Plugin 1.4. Enjoy all your CD's, WMA, MP3 and other streaming audio in 5.1 surround sound with SRS Lab's Circle Surround II (CAII) Plugin for windows media player 9 series. The CSII seamlessly integrates circle surround's powerful controls directly into the windows media player 9 series, enabling you to customize the multichannel audio experience on your PC.