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Analog Signal Processor - ASPThe ORION could not have been built without the use of
active line level crossovers and equalization. The various filter and gain
functions, which are necessary to derive the tweeter, midrange, and woofer drive
signals, are implemented with operational amplifiers, capacitors and resistors
forming an analog signal processor with one input and three outputs. Identical
ASP are used for left and right channels.
The location of each function block in the signal path is critical for obtaining the desired amplitude and phase response and to control signal levels at each stage for minimum distortion and noise. The function of the ASP could be duplicated with a digital signal processor, DSP, by realizing the poles and zeros of the different transfer functions, and following the same signal flow and gain distribution. Still great care must be taken to have enough dynamic range for each number processing stage to minimize non-linear distortion. Such custom DSP design is not trivial and requires good firmware programming knowledge and technique. I doubt that off-the-shelf DSP based crossovers have enough flexibility to duplicate the three outputs of the ORION ASP in magnitude, phase, distortion and noise level. It certainly is not just a matter of adjusting for similar magnitude response since the ASP is not minimum-phase. But, it could be a worthwhile learning exercise in digital filtering to obtain not only the magnitude and phase response, but also the dynamic range, distortion and noise performance of the ASP. It probably can be done, but it is not trivial. I would want to see actual measured analog output response and distortion data, taken over a realistic signal level and frequency range, to be convinced that off-the-shelf DSP is a simpler, or less costly way, to make an ORION crossover/equalizer.
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