Fraunhofer Expands MP3 Surround Sound Capabilities

The Fraunhofer Institute for Integrated Circuits IIS and Thomson have announced the addition of two new elements to the MP3 Surround demo software: MP3 SX (MP3 Stereo eXtended) allows enhancing MP3 stereo files for multi-channel playback and Ensonido provides portable MP3 Surround sound using stereo headphones.

MP3 SX enables listening to two-channel content in surround and guarantees playback with a stable localization of vocalists and solo instruments even off the sweet spot. Additionally, MP3 SX presents the feeling of envelopment by using the ambience sounds already present in the stereo source.

Traditionally, surround sound has been primarily limited to loudspeaker setups in living rooms or theaters. With the Ensonido technology, the individual listening experience through portable MP3 Surround players and stereo headphones is enhanced. To achieve this, an acoustic model simulates the natural transmission of multi-channel sound from the loudspeakers to the human ear.

MP3 Surround enables high-quality surround sound at bit rates comparable to those currently used to encode stereo MP3 material. It is backwards compatible to stereo MP3; a legacy MP3 device plays back MP3 Surround as high quality stereo.

MP3 Surround was developed by Fraunhofer IIS in collaboration with Agere Systems, introduced in December 2004 and is licensed by Thomson, co-inventors of the MP3 codec.

Demo software of these two new enhancements to the MP3 Surround technology are now available and can be downloaded for free at

Leave a Reply