I know little about these Roland MPU-401AT cards (short of their basic purpose), but how does one "get" the sound from the daughterboard to your computer speakers?
On an SB16/AWE32 with a wavetable header connector, the audio is piped to the sound card's internal/onboard mixer/audio bus via several pins in the connector. But, in the instance of connecting a DB to the Roland MPU-401AT, how does the audio get transfered/sent?
If the card included line output jacks (that would normally be fed to an external amplifier, or the line input of your sound card), I have a good hunch that it's strictly a line-level signal... in other words, the Roland MPU-401AT contains no amplifer or pre-amp. AFAIK, in that case, there prolly would be no way to control the connected DB's volume via software.