Sweet, after a bit of playing around, I got Marsyas running on my laptop.
Some things that might help you:
1) You need qt4 for some of the GUI tools - In Fedora Core 7, just use yum:
yum install qt4-devel
2) Some soundcards only support playback at 48000Hz, if you try to play a file that isn't at 48000Hz, you'll get a strange error from RtLib:
RtApi: no devices found for given stream parameters:
RtApiAlsa: error setting sample rate (22050) on device (hw:I82801CAICH3,0): Invalid argument.
RtApiAlsa: pcm device (hw:I82801CAICH3,1) won't open: No such file or directory.
RtApiAlsa: error setting sample rate (22050) on device (hw:Modem,0): Invalid argument.
3) When you're trying to record from the microphone, you need to set the capture device to be the microphone in alsamixer. You want to type:
alsamixer -V capture
Then move the selected device to the microphone with the left and right arrow keys and then press SPACE to select the microphone device. The spacebar was not the key that I was expecting to use, but the Wikipedia page for alsamixer helped me out. Thanks wikipedia!
(by the way, that's interesting, that's the first time that the Wikipedia page for a program was more helpful than the man page or "-h". Maybe Wikipedia will be the best manual for programs in the future. Neat)
