The new Reference Series crossovers are computer-modelled to optimise integration. The boards are decoupled to isolate them from cabinet vibration and internal acoustic pressures, and three-tier construction eliminates crosstalk. High saturation iron core inductors are used for the bass sections, with more linear air-cored inductors elsewhere; bipolar capacitors for low frequencies, with very low loss polypropylene capacitors for the upper ranges. Wire-wound resistors minimise compression and maximise linearity.