thebarmaeffect/echo

Echo is an audio engine designed to take a normal, flat sounding music track and turn it into a spatial listening experience through headphones, the kind where sound feels like it is coming from specific points in space around the listener rather than just left and right. It is part of a product family called Aura. Instead of applying a quick effect on top of a finished mix, Echo works by rebuilding an explicit, inspectable model of the sound scene first, something the project calls a sound scene graph. Every version it produces, whether a headphone friendly binaural mix or other output formats, is generated from that underlying scene model rather than being a one-off tweak, so it can be regenerated or adjusted later. The project is careful to describe itself honestly: it is an offline tool that processes a finished audio file rather than something running live during a performance, and running it twice on the same input produces an identical result down to the byte. It is built using common scientific computing tools in Python. The project is explicit that outcomes like a sound feeling like it is truly outside your head, or feeling enveloping and intimate, are goals it is designed to work toward rather than guaranteed results, and it keeps a public log of measured test results rather than only describing intentions. Alongside the core spatial engine, Echo includes a toolchain for mastering a track, meaning cleaning it up and adjusting its loudness to a professional standard, and for creating an immersive up-mix version of a track. Every output from these tools checks itself against a set of measured quality rules before it is considered finished. There is also a simple browser based listening tool that plays different versions of a render back to back so a person can compare them fairly by ear. The code and documentation in this repository are released under the Apache 2.0 license. A demo video and its music are not covered by that license and remain fully owned by their creator.