XPost: sci.electronics.basics   
   From: spam@spam.com   
      
   On Sat, 19 Nov 2011 18:05:11 -0600, "krw@att.bizzzzzzzzzzzz"   
    wrote:   
      
   >On Sat, 19 Nov 2011 18:23:36 GMT, spam@spam.com (Don Pearce) wrote:   
   >   
   >>On Sat, 19 Nov 2011 12:17:35 -0600, "krw@att.bizzzzzzzzzzzz"   
   >> wrote:   
   >>   
   >>>On Sat, 19 Nov 2011 10:16:43 GMT, spam@spam.com (Don Pearce) wrote:   
   >>>   
   >>>>On Sat, 19 Nov 2011 20:22:43 +1100, "Trevor"  wrote:   
   >>>>   
   >>>>>   
   >>>>>"Don Pearce"  wrote in message   
   >>>>>news:4ec76c21.174471@news.eternal-september.org...   
   >>>>>> On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD   
   >>>>>>  wrote:   
   >>>>>>   
   >>>>>>>What's the difference between reverb, echo,  and feedback?   
   >>>>>>   
   >>>>>> Echo is a single reflection of a sound - the kind you hear when you   
   >>>>>> shout "Hello" near a cliff.   
   >>>>>   
   >>>>>Multiple reflections are also common in such instances.   
   >>>>>   
   >>>>   
   >>>>No they are not. One cliff, one echo. No choice.   
   >>>   
   >>>Two walls of said cliff; multiple echoes.  If you're on the edge of the   
   cliff   
   >>>with no opposing wall there will be zero echo.   
   >>>   
   >>Since when does one cliff have two walls? The cliff IS the wall.   
   >   
   >Zero intelligence.   
   >   
   >>>>>> Feedback is a situation you only get when you have an amplifier and a   
   >>>>>> speaker. The sound arriving from the speaker is a little louder than   
   >>>>>> the one that originally hit the microphone, so that comes out of the   
   >>>>>> speaker a little louder still. This loop will build until the system   
   >>>>>> howls.   
   >>>>>   
   >>>>>That would be *acoustic feedback* only, There are MANY other types of   
   >>>>>course.   
   >>>>>   
   >>>>In the context of the question it would simply be confusing to discuss   
   >>>>- or even mention - other kinds.   
   >>>>>   
   >>>>>>You cure it by turning down the amplifier so the sound from the   
   >>>>>> speaker is always a little softer than the original when it hits the   
   >>>>>> microphone.   
   >>>>>   
   >>>>>Or any other method that reduces the loop gain at the feedback frequency,   
   >>>>>notch filtering being a common example.   
   >>>>>   
   >>>>   
   >>>>Again, given the question, no need to complicate the answer.   
   >>>   
   >>>But you found it necessary to bring up loop gain.  Interesting.  You   
   wouldn't   
   >>>be an audiophool, by chance?   
   >>   
   >>Loop gain greater than unity is what causes feedback howl. There is no   
   >>way of avoiding it if you want to explain what causes the feedback.   
   >   
   >Wrong.  *Regenerative* feedback needs a gain > unity.   
   >   
   >>And make no mistake, the feedback the OP was asking about was the loud   
   >>howl you get when you turn the PA up too far.   
   >   
   >You can't even keep *your* terms straight.  You *must* be an audiophool (lack   
   >of an answer speaks volumes).   
      
   I leave the verdict to the audience.   
      
   d   
      
   --- SoupGate-Win32 v1.05   
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