Sony is packing its new Walkman digital music players with noise cancellation and other audio-enhancing technology in its latest attempt to challenge the dominance of Apple's iPod.

"The strongest point is audio quality," said Hiroshi Yoshioka, corporate senior vice president of Sony and head of its Walkman division, which intends to make the noise-cancelling technology the centrepiece of its portable music marketing.

The system is tuned to cancel out background noise in the 100Hz to 1KHz range, a particular problem on trains, aircraft or cars.

On the new Walkmans, a microphone to detect the noise is integrated into the headphones, which means listeners must use the supplied headphones for the noise cancellation to work. In a demonstration today, the headphones did a good job of cancelling out simulated train noise.

The technology is something that really has to be experienced to be understood, Sony said, so it is planning to offer demonstrations in shops across Japan.

Two other features, both of which are headphone independent, include "clear stereo", a system that separates the left and right channels and stops audio bleed between them, and "clear base", which improves the bass response.

The players have a battery life of 50 hours, and can display album art on a small colour OLED (organic light-emitting diode) display panel. Listeners can search through their music by song name, album name or artist name.

The players are compatible with MP3, Windows Media, AAC, ATRAC, ATRAC Advanced Lossless and Linear PCM audio files. However, they won't play Windows Media or AAC tracks encoded with DRM (digital rights management): that limits downloads of DRM-protected tracks to stores using Sony's ATRAC system.

The products in the new S700-series include an FM radio and will come in versions with 4GB, 2GB or 1GB of memory. They will cost around ¥29,000 (£130), ¥23,000 (£105) and ¥18,000 (£80) respectively.