The ROSSO 460 employs state-variable 4th-order Linkwitz-Riley filter alignments to minimize phase difficulties in the critical crossover region. Simply put, a Linkwitz-Riley alignment is two cascaded 2nd order Butterworth filters exhibiting identical phase characteristics on their low pass and high pass outputs. This characteristics guarantees in-phase outputs at all frequencies. In-phase outputs are mandatory for proper acoustic summing of common signals from adjacent drivers in the crossover region. An added benefit of this topology is steep 24dB per octave rolloff slopes. A slope of this magnitude guarantees drivers designed to produce a specific range of frequencies, and no more, will not be driven past their limits, thereby minimizing distortion and drive fatigue.
General crossover characteristics:
- Alignment: Linkwitz-Riley.
- Slopes: 24dB per octave.
- High quality passive components (1%, 100ppm/K resistors, 2% PPS film capacitors).
- Low noise, low THD op amps (THD+N < 0.0006%).
- Signals routed through sealed electromechanical switches.
- DC coupled stages (LF sections).
- Cut off frequency and LF gain user-adjustable.
The main key-parameters are user modifiable through the serial interface and can be stored into the non-volatile memory of ROSSO 460. Simply put, the product can operate according three different modes: setup1 (standard), setup2 (mono subwoofer) and setup3 (flat).
Setup1
The setup1 is the standard mode. In this mode each channel (left and right) is split up into a Low Frequency section (LF) and in a High Frequency section (HF) by the electronic crossover. The adjustable parameters are:
- Crossover frequency (70,75,80,90,120,180,250,300,400,500,700,1000,1400, 1900,2700,3600 Hz)
- LF section amplitude (-12...+12 dB, with resolution of 0.1 dB)
Setup2
Select the setup2 if you want to drive a mono subwoofer loudspeaker. The LF sections amplify the same signal so the outputs can be paralleled in order to double the power capacity and to halve the load impedance. Alternatively the two LF outputs can be used to drive two woofers in push-pull topology. The adjustable parameters are the same of the setup1 mode.
Setup3
The setup3 is the flat mode. In this mode the internal crossover is by-passed and all the four amplifiers operate as full-range amplifiers. Besides, the outputs of section LF and section HF can paralleled together so to drive extremely low impedance loads (for example some particular electrostatic loudspeakers). This mode doesn't expect adjustable parameters.
