Alsa and software speech

[Zachary Kline]

Hello,
    I am dealing with a fairly annoying problem--one which seems quite complex.  How do I achieve software mixing with Alsa?  (I want to be able to play an MP3 stream and also have software speech going.)  The information I've found so far seems to center on a file named asoundrc--which I've never heard of before, and who's format is a mystery to me.
    Could anybody be so kind as to give some general information on this?  What is Dmix, for example?
Thanks,
Zack.