XPost: sci.electronics.design   
      
   Clive Arthur  wrote in   
   news:tp0uv4$23lge$1@dont-email.me:   
      
   > On 03/01/2023 02:30, Brian Gregory wrote:   
   >> On 02/01/2023 13:48, Rink wrote:   
   >>> If you change the wires of one speaker you get a 180 degree   
   >>> difference on all audio frequencies.   
   >>> If from two speakers at the some radio (left and right), one is   
   >>> wrong connected, you can hear that at exactly the middle between   
   >>> the speakers where there is a fase-out for all audio   
   >>> frequencies.   
   >>   
   >> I've never heard an audible null between out of phase speakers.   
   >> It usually just ruins the stereo effect, makes it sound almost   
   >> like two separate lots of music (or whatever).   
   >>   
   > With a mono source (ie both channels the same phase) you lose a   
   > lot of bass in the centre.  Block one ear and the effect is   
   > clearer and at higher frequencies too.   
   >   
   > A long time ago, when stereo records were often mixed with the   
   > vocals in the middle and other instruments to the sides, inverting   
   > one channel and adding it to the other channel (ie subtracting it)   
   > could do a not-too-bad job of removing the vocals for karaoke.   
   >   
      
     And then, in 1971 IIRC, came "quadrophonic"   
      
     Heathkit had an amp and there were quadrophonic album pressings.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)