For the "analog output is only 2CH" in the software interface, you can ignore it. Because the settings there have no affecting for the final playback effect. You don't need to worry about whether there is only 2CH analog output option on the driver interface.
 

The H951BT PC-USB input is based on CM108 chip, which has powerful functions, including 2CH analog output and S/PDIF digital output, even mixing effect, etc., All of these will be displayed on the interface.
 

But the H951BT only uses its S / PDIF Digital Output function, output to another more professional AC3 / DTS 5.1 decoding chip by S / PDIF Digital, decode it into 5.1 analog output. The CM108 The 2.0 analog function of the chip is not used in our products, even if the chip with 2.0 analog output. So we just need Select S / PDIF output, others we can ignore.