And now, the Xonar DSX
With a $49 asking price, the Xonar DSX costs just $7 more than the standard DS. That's more like it. But the DSX still costs nine bucks more than the DGX, so it has to outdo its headphone-focused sibling.
If you haven't been paying close attention, you'd be forgiven for mistaking the DSX for the DGX. The two look very similar, right down to the size of their half-height circuit boards. Like the DGX, the DSX comes with a midget backplate. The card also has the same internal input and output headers. However, there's no headphone amp onboard.
Instead of boosting headphone output, the Xonar DSX lets users choose how to amplify stereo sound. The front channel is fed through a socketed operational amplifier that users can replace easily on their own. A chip-puller is ideal for the task, but the op-amp can be separated from the socket with no more than a small screwdriver.
The DSX's op-amp socket is filled by a Texas Instruments NE55329. Asus told us at the Computex trade show earlier this year that socketed Xonars are outfitted with neutral-sounding op-amps by default. If users crave a particular acoustic profile, they can swap in a different chip.
Because it applies to just the front channel, the op-amp can only shape the sound coming out of two speakers. Headphones plugged into the green port at the rear will be affected, but the op-amp doesn't touch signals going to the front-panel headphone connector or to the card's rear, side, or center/sub outputs.
With one more output channel than the Xonar DGX, the DSX has to resort to sharing to fit all of its ports on a half-height card. The rear-channel output uses the same jack as the digital S/PDIF out. Asus includes a TOS-Link adapter for the 3.5-mm port, but you'll need to supply your own optical cable to use the digital connection.
There's some temptation to go digital, because the Xonar DSX supports DTS Interactive, a real-time encoder capable of mixing surround-sound bitstreams on the fly. Everything from games to movies can be pumped to a compatible receiver or speakers over a single digital cable instead of the mass of analog cords usually required. The Xonar's DTS implementation also features Neo:PC, which can expand stereo sources to pseudo-surround sound. Neo:PC comes with strings, though. It has to be used with DTS Interactive, restricting surround-sound simulation to digital output.
The Xonar DX's drivers look all but identical to those of the DGX. A few of the options are different, but the two drivers share a common interface. They have the same mixer and equalizer, plus access to the same suite of effects.
Of course, the DSX drivers have a few special knobs to twirl related to DTS. The DTS Interactive mode features a speaker shifter that allows users to map how their speakers are laid out in the room. The software should adjust the audio fed to each speaker accordingly. Folks can also tweak a couple of sliders related to how Neo:PC expands stereo sound. There's no echo-cancellation mode, though.