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                                                            Paul S
                                                        
                                                        
                                                             San Diego, California, USA
                                                             Posts 2,797
                                                             Joined on 10-12-2006
                                                        
                                                         
                                                        
                                                            
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                                                                        26118
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                                                        Robin, your point is well taken, but I don't think they are trying to circumvent the laws of physics here. I did not read it yet, but Alexandre did provide a link that gets one in the vicinity of an explanation:
  https://www.ds-audio-w.biz/wp-content/uploads/2021/03/EQ-infover1.02.pdf
  Clearly, this EQ system is based on the RIAA curve embedded in the LP grooves, and just as clearly it might be adapted to other recording curves.
  Not saying I understand how it operates so precisely, to begin with, but I have heard that optical readers are integral parts of high speed manufacturing processes that are just as amazing, in use all day, every day, around the world.
 
  Best regards, Paul S
 
                                                        
                                                        
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