[Trevor]

"Don Pearce" wrote in message
...
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.

In the real world cliffs are not usually one straight smooth edge of course.


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.

If you prefer to simplify things so much you at least need to point that
out.


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.

Or simplify it to the point of being wrong. To paraphrase Einstein, things
should be as simple as possible, not simpler.

Trevor.