RCF's new generation of speakers include an innovation in the processing: FiRPHASE, a proprietary and advanced FIR filtering technology, conceived for delivering transparent sound, absolute clarity and perfect stereo images to the listener. The FiRPHASE algorithm optimizes dynamics, amplitude and phase patterns, ensuring at the same time minimum system latency.
The design of the FIR filter for this specific purpose should start from an accurate measurement of the loudspeaker phase. The FiRPHASE algorithm uses this measurement and adapts the loudspeaker’s phase without touching the amplitude equalization. The heart of the advanced technique used by FiRPHASE is a recursive method (Least Squares method) combined with a proprietary algorithm that calculates the best FIR filter coefficients set in according to amplitude and phase constraints. The algorithm corrects phase and amplitude (when necessary) by taking into account the weak points of the transducers and the resonances or cancellations due to the cabinet of the loudspeaker. Despite the design perfection of our transducers and cabinets, we realize that the phase corrections are the “missing point” for the best sound reproduction. This technique allows a deep control of phase at mid-low frequencies with relatively small filters, reaching a higher resolution than that one as theory suggests.