The Phonofone is a gramophone-style acoustic amplifier for your MP3 player — dock your headphones in its core and it will amplify it to by 55dB.
Without the use of external power or batteries, the Phonofone inventively exploits the virtues of horn acoustics to boost the audio output of standard earphones to up to 55 decibels* (or roughly the maximum volume of laptop speakers)
Upon connecting active earphones to the Phonofone their trebly buzzing is instantly and profoundly transformed into a warm, rich and resonant sound.
(via Gizmodo)