Physis technology, is our latest attempt to revolution the classic organ market, showing it’s time to change the old PCM sound generation paradigm. A sampled note will always sound unnatural, no matter how many tricks you use to resemble a real pipe organ. Physis technology, calculates instead, in real-time the physics of a flue, reed or bourdon pipe. The result is a living organ, changing in real time, resembling the organ you prefer, or creating a new sound. Let’s explain this with a few examples. What if a GPS navigator had to know every possible route instead of calculating it for you in real-time? What if we had to film the Titanic sinking instead of calculating and rendering the scene with computer-graphics? What if we had no physical models to forecast the weather? Physis technology is the answer to all these questions. Physis technology is our implementation of physical modeling applied to organ pipes, something no one has ever tried before. It is the culmination of years of technological evolution.
Tech talk: an organ pipe can be seen as a mechanical multi-modal waveguide resonator. The input air flow stimulates the pipe, which after a variable attack time starts oscillating. The upper termination determines the harmonic components to be filtered, hence acts as a filter, while the lower termination is subject to regressive waves, which are added to the stimulus with a non linear law. This whole mechanism is in feedback. This provides a high dependence on small random changes, generating remarkable modifications in the sound from time to time, as in every real pipe organ. The algorithms take into account every physical and mechanical parameter of the air and the pipe, including shape, material, terminations shape and dimensions, incoming air pressure, etc. This leads to many benefits, including a more realistic “ensemble” effect, because all the pipes are playing and resonating together, subject to the same airflow, variable attack and decay times, realistic harmonic recreation (no artifacts from pitch-shifting samples), no split points. Remarkably, the air pressure changes in dependence to the amount of active stops, like in real pipe organs. Another important benefit is the fast and complex attack after ribattuto: if we press a key twice in a short time, the pipe starts resonating with a certain attack time after the first key has been struck, then if we do not leave enough time for a complete decay, the second time we strike the key, the attack time and resulting sound will be different and richer from the first time. A sampled sound would just repeat unchanged.
Digital Signal Processing: Physis organs hide, inside elegant woodwork furniture, up to eight powerful DSPs, to generate sound. The DSPs in use belong to the SHARC family, and have working frequency of hundreds of MHz, and performances close to, and higher than common PC CPUs (up to GFLOPS, i.e. Billions of Floating Point Operations per Second). They are used to calculate in real-time the aerodynamics of flute, reed, bourdon pipes, metal, following complex mathematical models. Reverberation is another important step in the processing chain, requiring the knowledge of the position and spatial parameters of the pipes, ambience dimensions, and windchester layout, which can be adjusted stop by stop. The sound finally routed in the proper way throughout up to 20 external out connections.
