A German company is offering MP3 files for download, unencumbered by DRM (digital rights management). Instead, Akuma discourages copying by adding a unique 'watermark' to each download.

Major record labels have mostly chosen DRM to protect their copyrights, limiting the number of copies buyers can make of a downloaded track and restricting the music players they can use to listen to it.

However, Akuma is taking a softer approach: the music store sells MP3 files that can be played on almost any digital music player, but adds a unique tag to each download using watermark technology from Germany's renowned Fraunhofer Institute for Integrated Circuits, which helped create the MP3 audio compression algorithm.

The watermark technology makes slight changes to the data in sound files, such as a higher volume intensity in a tiny part of a song, that are undetectable by even the best-trained ears, according to Fraunhofer researchers. However, if unauthorised copies of a download turn up on, for example, P2P (peer-to-peer) filesharing networks, the watermark allows Akuma to identify the purchaser of a file and take action against them.

"Around 40 percent of the labels we offer are embedded with watermarks," said Sascha Hottes, a managing director of H2 Media Factory, which launched Akuma. "This is the compromise we've reached with labels that are willing to release their titles in the MP3 format and not in Microsoft's Windows Media Audio format with its DRM technology."

As part of its service, Akuma monitors songs embedded with a watermark against illegal distribution on P2P services, according to Hottes. "We monitor P2P networks on a random basis," he said.

Around 350,000 songs, mostly from independent labels, are currently available on the Akuma portal, with 700,000 planned by the end of the year. The roster includes artists from Simply Red to Deep Purple.

A single song title costs €0.89 (about £0.60), an album €4.49 (£3). Customers have various payment options: online, direct debit, telephone invoice and PayPal.

Akuma offers MP3 files at a quality similar to CDs, with bit rates from 192Kbps (kilobits per second) at the low end to 320Kbps at the high end.

Like eMusic, the German music download store hopes to break into a crowded market by making song downloading a piece of cake. The German portal requires no special download software and places no restrictions on the choice of music player, including the iPod from Apple.

Customers can make as many copies of the songs as they like, burn them to CD and transfer them onto multiple portable music players.

The Akuma portal is now available in a beta version to registered users.