[alsa-devel] newbie questions on alsa architecture (e.g. who reads .asoundrc)

hello i recently found that a few android devices build their audio stack upon alsa (SGSII for example), and become interested in creating an audio output capture application through alsa api (since android stack does not support such feature) Some tutorials suggest .asoundrc tweaks work for pc, so i want to know what happens when a copy device line is added to the conf file, and is that possible to achieve the goal through plain api calls. i'm ok if a kernel rebuild is necessary, just hoping to dig into alsa a little deeper.