Using such perceptual tools as Head Related Transfer Function (HRTF), the @ PET RP-U100 creates a realistic surround environment with only two speakers. The sound field created by virtual surround technologies is optimized for computer users, since the position of the listener is known and the listening area is relatively narrow. In addition to the receivers controls, the computer screen provides an easy-to-read display for control and operation of the receiver via a mouse. In addition to Virtual Dolby Digital, the @ PET RP-U100 provides six different DSP modes with user adjustable parameters for Effect, Initial Delay and Room Size. Based on Yamahas sound field sampling over more than a decade, three proprietary DSP modes enhance Dolby Pro Logic and other full-surround technologies and include: Movie (to recreate the acoustics of a true movie theater), Live (which immerses the listener in a rich sea of sound) and Game (to add immediate impact and greater involvement to game play).
The Yamaha RP-U100 is a great small receiver with the bonus of a USB link for PC use. I have used it extensively for copying old tapes and records to digital format (note, you need an additional pre-amp if you are using a turntable, as the RP-U100 does NOT have an phono input). Although the RP-U100 was designed back when Windows 98 was popular, it does seem to work with Windows XP, although I've read some reviews where some folks have had troubles with this.
The ability to use USB 1.1 (sorry, post-USB 2.0) provides better sound quality than going from your stereo amplifier to you sound card analog inputs.
I don't know that I would buy it today as there are many more USB DACs available on the market today and software support for this system is long past, but if you come across a used one it might be well worth your while. Back in 1999, it was highly rated by Stereophile magazine as well!