RCF speakers are designed using a proprietary and advanced FiR filtering technology, conceived to deliver transparent sound, absolute clarity and perfect stereo images to the listener.

The special FiRPHASE filters allow to achieve coherent distribution of sound for all listeners without phase distortions, ensuring minimum latencies to the system.


The design of the FIR filter for this specific purpose should start from an accurate measurement of the loudspeaker phase.

FiRPHASE algorithm use this measurement and adapt 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 constrains. The algorithm corrects phase and amplitude (if necessary) by taking into account the weak points of the transducers and the resonances or cancellations due to the cabinet of the loudspeaker. This technique allows a deep control of phase at mid-low frequency with relatively small filters, reaching a higher resolution than that one as theory suggests.

Thanks to the 0° phase response, all the FiRPHASE speakers are acoustically compatible. In other words, if you use FiRPHASE speakers as downfill, sidefill or infill, there is no need to adjust the phase response.

ANDREA CAPRA, R&D Electroacustic Engineer

Explains the RCF proprietary FiRPHASE Technology

Read our technical White Paper to discover all the features about the proprietary RCF FiRPHASE Technology