The ATSurround Processor is a DSP plugin for the foobar2000 and Winamp audio player.
The ATSurround Processor performs audio matrix decoding to extract surround information inherently present in many music and audio sources to enhance the listening experience. This ensures that your 5.1 system is fully utilized.

Many songs today found on CDs, MP3s, etc. have surround information encoded. Even when played on a 5.1 PC system, the surround channels may not be extracted from the audio as it is processed from start to finish as a 2 channel source. What you get as a result is simply many speakers playing exactly the same sound, which does not enhance the audio. A surround decoder such as the ATSurround Processor is required to extract the encoded surround information for playback.

The process of extracting surround channels and routing it to the appropriate speaker is known as matrix decoding. Hardware and software decoders are available for this purpose. The ATSurround Processor is a software decoder designed to work as a plugin in the foobar2000 and Winamp players. Multichannel output capable soundcard and speakers are required.

The Headphone mode allows the listening of audio sources which sound like they're really coming from a live 5 point surround system. Music no longer sounds like it's "inside" your head, listening fatigue is thus reduced. Perfect when you don't want to disturb anybody around you by using headphones, but don't want to sacrifice the surround decoding capability of ATSurround.

ATSurround Processor is also capable of performing matrix encoding. The Processor receives multichannel audio and matrixes it into stereo. This stereo output may be distributed via any 2 channel medium, such as CD-Audio and MP3 or direct to an external audio receiver which performs audio surround decoding, useful when the receiver is connected using a stereo cable.

Features of ATSurround Processor 0.1.6 :

- Reproduces surround sound information present in many stereo audio material
- Headphone mode allows listening of audio in virtual surround
- Compatible with Dolby® or similar processors
- Makes full use of your 5.1 speaker systems
- Bass redirection for discrete 5.1 satellite systems
- Surround channel delay
- Channel amplitude trim
- Converts multichannel audio into surround encoded stereo audio

Changes in ATSurround Processor 0.1.6a :

• ATSurround Processor 0.1.6a for foobar2000
- Fixes bug causing foobar2000 to remain in memory after closing.
• ATSurround Processor 0.1.6 for Winamp and foobar2000
- Added system tray icon to change processing modes.