Hi
Sugestion is to Develop a programme in Matlab (or the language you wish to develop skill C, VB, LabVIEW etc) which will do the following things..
1) Get the MP3 file from user
2) Decode the MP3 file
3) Drive the speaker
For decoding MP3 file, Strong understanding of file format is needed
MPEG-1 or MPEG-2 Audio Layer 3 (or III), more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression. It is a common audio format for consumer audio storage, as well as a de facto standard of digital audio compression for the transfer and playback of music on digital audio players.
Two standards are governing the MP3 standards
MPEG Version 2 (ISO/IEC 13818-3)
MPEG Version 1 (ISO/IEC 11172-3)
This link
MP3 - Wikipedia, the free encyclopedia has some basic information to understanding about file structure, you may wish to refer this also
MP3 File Structure [HowTo]
coming to the programming part refer official website for mp3
MP3'Tech - www.mp3-tech.org (check "programmer's section" )
codes are available in Mathworks (Matlab's official website). Temptation will be there to check. But my suggestion will be to "try to develop your own code and compare with the codes available there)
once MP3 file has been decoded you may wisht to do
1) Zero crossing rate
2) Average energy
3) Auto correlation
4) power spectrum analysis
5) Fourier transform
Hope this helps you...