The large usage of multimedia portable devices has contributed to rapidly increase the demand for multimedia entertainment services. In this paper we focus on the karaoke service: several systems have been proposed but they are too difficult to be directly used over audio devices. Conversely, in this paper we propose a very simple approach to provide a karaoke-like service over any audio device that can play out mp3 files. Our approach is essentially new, as no additional files, beyond the mp3 file, are necessary. A simple description language has been designed to characterize audio-text timing synchronizations, which are transparently stored inside the mp3 file. The effectiveness of our approach is proved through a developed java mp3 player. The simplicity of our approach along with java portability allow a straightforward use of our player over any OS and over any audio device that supports java applications.