How can I enable mixing with the “Direct Audio Device” mixers on Linux?
The “Direct Audio Device” implementation on Linux is based on ALSA. Mixing is available in the Mixer instance if ALSA provides mixing. This is the case if the soundcard can do mixing in hardware and its ALSA driver supports this feature. This is true for some common soundcards like Soundblaster LIFE! and Soundblaster Audigy and cards based on the Trident 4D Wave NX chipset. If this feature is available at all, it needs no special configuration. It is enabled by default. Using ALSA’s dmix plug-in does not work together with Java Sound. The reason is that the “Direct Audio Device” mixer implementation based on ALSA queries the available hardware devices. However, a dmix device in ALSA is no hardware device, so it is not recognized. Discussions about this issue led to the conclusion that there is no easy way to integrate a query for additional devices. See also Q: 3.
