From: info@turneraudio.com.au   
      
   True, & true.   
      
   HOWEVER: a couple of times I have made myself look godlike (and that is a vast   
   stretch even to the best of imaginations) to a certain class of audiophile by   
   the simple expedient of connecting their speakers correctly (in phase). On one   
   very special    
   occasion, I had to practically tie one gentleman down as he INSISTED that the   
   right speaker should be connected one way, the left the other way. Until he   
   heard them connected properly.   
      
   So, relative phase angles may be inaudible. But 180 degrees out of phase is   
   most definitely audible.   
   - hide quoted text -   
      
   Peter Wieck   
   Melrose Park, PA    
      
   Phase and audiophiles are not happy marriage material. Phase is a bad word,   
   because ppl talk in terms of being un-phased as a negative experience, and of   
   course NFB is also evil, because its damned negative, and saying it ought to   
   be called "inverse    
   feedback" simply makes audiophiles feel queasy about listening to music   
   standing upside down, or mounting their amps upside down, ie, something must   
   be inverted to counter the inverted NFB.    
      
   I don't know how many times I corrected phase for sub-woofers which wen   
   connected by the audiophile made overall bass worse, while putting in an   
   unwanted boom below 30Hz. Measurements at the listening chair were usually   
   appalling, only able to be    
   improved marginally.    
      
   It is standard practice by hundreds of speaker manufacturers to have phase of   
   bass and tweeter with "normal" phase, then with midrange deliberately "reverse   
   phase" connected. I've done it myself in nearly all 3 way speakers I made.    
   One will find it is THE WAY to get a smooth transition of response between   
   bass-mid, and between mid-tweeter, when correctly damped C&L second order   
   crossover filters are used.    
      
   Its stupid to worry that the midrange is 180d to bass and tweeter. The   
   essential thing is a flat response, and SAME phase shift of L and R speakers   
   in order to get the best stereo imaging. The only time I have heard any one   
   tell me they didn't like the    
   phase behavior of a speaker was because L and R had different measurements, or   
   someone has replaced a driver and one speaker driver was wrongly phased, and   
   then they couldn't understand why a singer seems to be to the left of a LEFT   
   speaker, when we all    
   know she was standing centre stage when recorded.   
      
   Music produced at a live venue has instruments placed at many different   
   distances to our ears, and yet it makes SFA difference if the musos change   
   distance by plus or minus maybe several or dozens of wavelengths, so we never   
   ever can hear music at our    
   ear without the phase analomies occurring because of varied path length. Much   
   sound indoors is reflected, there is a huge amount if phase cancellations and   
   additions, but they sum to give an average level, and its no use thinking   
   about it all because it'   
   d lead to maths equations that are too complex to have meaning, even if worked   
   on with super computer. So what you hear is what you get, and live music needs   
   a nice venue not too reverberent,   
   and we also need a good room to reproduce that overall "room atmosphere" - and   
   remarkably, if some extra phase jiggery-pokery is added in speaker making, but   
   speakers are good quality, we really do hear what we heard live at the venue.   
      
   Scientific American did tests back in 1950s or 60s to find out if ppl could   
   hear phase change. Nobody could. You play music with speaker leads reversed at   
   amp or normal, and nobody could pick it.   
      
   But audiophiles are so often not at all scientifically minded, and go through   
   life never ever understanding any formula or technical concept. They will   
   often claim to hear or not hear some peculiar thing in their systems, without   
   their being the    
   slightest real evidence to cause the perceived phenomena, and gently I have   
   had to just demonstrate by doing and measuring and comparing to put them at   
   ease - until next time they find a reason to change amps or speakers. I have   
   surprised myself when I    
   improved total quality of what I made over a number of years which made it   
   easier to sell my gear. If the audiophiles liked what I made, and if they   
   changed houses and it all still sounded well, then that WAS really something.    
      
   Oh, and BTW, just about all recorded music has huge post recording processing   
   done on the music, often digitally, and STILL we get some excellent recordings   
   that are so good the word PHASE just never enters our mind.   
      
   Patrick Turner.    
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)