Right away the primary design goals of the MX400 become clear from the specifications Diamond's listed for their new card.

First the enabling of the 32 simultaneous audio streams is made clear, as is the focus on "True Quad Playback", meaning that, unlike the MX300 which used a panning technique to produce sound to the rear speakers, the MX400 is able to fully utilize four speakers with digital clarity.

The next spec on the MX400's sheet you'll notice is the "Rio Upgrade" which is basically a daughter card that will allow for true digital encoding and playback of MP3 files, along with the addition of a stereo FM receiver within your PC. While the cost of this add-on board isn't yet known, we've been told that a range of $25 - $40 seems likely at the time of its launch (Q1/2000).

The MX400 offers support for PC-based DVD home theater setups through its inclusion of the Dolby Digital 5.1 audio format via the MX400's included S/PDIF digital out port. Previously MX300 owners had to purchase the MX25 daughtercard to get this level of support with their card, we're glad to see that Diamond has included it right out of the box in the MX400.