R
RichD
Guest
What's the difference between reverb, echo, and feedback?
--
Rich
--
Rich
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John Fields
Guest
On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
<r_delaney2001@yahoo.com> wrote:
Reverberation is the persistence of sound in a particular space after
the original sound is removed.[1] A reverberation, or reverb, is
created when a sound is produced in an enclosed space causing a large
number of echoes to build up and then slowly decay as the sound is
absorbed by the walls and air.
http://en.wiktionary.org/wiki/echo#Noun
A reflected sound that is heard again by its initial observer.
http://www.thefreedictionary.com/feedback
Sound created when a transducer such as a microphone or electric
guitar picks up sound from a speaker connected to an amplifier and
regenerates it back through the amplifier.
--
JF
<r_delaney2001@yahoo.com> wrote:
http://en.wikipedia.org/wiki/ReverberationWhat's the difference between reverb, echo, and feedback?
Reverberation is the persistence of sound in a particular space after
the original sound is removed.[1] A reverberation, or reverb, is
created when a sound is produced in an enclosed space causing a large
number of echoes to build up and then slowly decay as the sound is
absorbed by the walls and air.
http://en.wiktionary.org/wiki/echo#Noun
A reflected sound that is heard again by its initial observer.
http://www.thefreedictionary.com/feedback
Sound created when a transducer such as a microphone or electric
guitar picks up sound from a speaker connected to an amplifier and
regenerates it back through the amplifier.
--
JF
P
Phil Allison
Guest
"Rich Dope"
** Depends on the context.
Digital delays and tape echo machines have controls with these names.
.... Phil
What's the difference between reverb, echo, and feedback?
** Depends on the context.
Digital delays and tape echo machines have controls with these names.
.... Phil
V
VWWall
Guest
John Fields wrote:
the circuit is "fed back" to a point earlier in the circuit. Depending
on its phase, this can be either negative or positive feedback.
--
Virg Wall
Or, in an electrical circuit, when the voltage or current at a point inOn Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
r_delaney2001@yahoo.com> wrote:
What's the difference between reverb, echo, and feedback?
http://en.wikipedia.org/wiki/Reverberation
Reverberation is the persistence of sound in a particular space after
the original sound is removed.[1] A reverberation, or reverb, is
created when a sound is produced in an enclosed space causing a large
number of echoes to build up and then slowly decay as the sound is
absorbed by the walls and air.
http://en.wiktionary.org/wiki/echo#Noun
A reflected sound that is heard again by its initial observer.
http://www.thefreedictionary.com/feedback
Sound created when a transducer such as a microphone or electric
guitar picks up sound from a speaker connected to an amplifier and
regenerates it back through the amplifier.
the circuit is "fed back" to a point earlier in the circuit. Depending
on its phase, this can be either negative or positive feedback.
--
Virg Wall
K
krw@att.bizzzzzzzzzzzz
Guest
On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD <r_delaney2001@yahoo.com>
wrote:
wrote:
DelayWhat's the difference between reverb, echo, and feedback?
R
RichD
Guest
On Nov 18, "k...@att.bizzzzzzzzzzzz" <k...@att.bizzzzzzzzzzzz> wrote:
--
Rich
Aren't they all delay?What's the difference between reverb, echo, and feedback?
Delay
--
Rich
K
krw@att.bizzzzzzzzzzzz
Guest
On Fri, 18 Nov 2011 16:56:56 -0800 (PST), RichD <r_delaney2001@yahoo.com>
wrote:
shorter than the decay, it's feedback. Greater than that it's reverb until
you can distinguish the individual images. Then it's echo. ...at least
that's how I see it.
wrote:
Different delay (and decay). If the delay is on the order of a wavelength andOn Nov 18, "k...@att.bizzzzzzzzzzzz" <k...@att.bizzzzzzzzzzzz> wrote:
What's the difference between reverb, echo, and feedback?
Delay
Aren't they all delay?
shorter than the decay, it's feedback. Greater than that it's reverb until
you can distinguish the individual images. Then it's echo. ...at least
that's how I see it.
D
Don Pearce
Guest
On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
<r_delaney2001@yahoo.com> wrote:
shout "Hello" near a cliff.
If you put together many echoes, arriving from different distances
into a jumble that you can't distinguish - that is reverb. You get
that in, say, a large church.
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. 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.
d
<r_delaney2001@yahoo.com> wrote:
Echo is a single reflection of a sound - the kind you hear when youWhat's the difference between reverb, echo, and feedback?
shout "Hello" near a cliff.
If you put together many echoes, arriving from different distances
into a jumble that you can't distinguish - that is reverb. You get
that in, say, a large church.
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. 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.
d
T
Trevor
Guest
"Don Pearce" <spam@spam.com> wrote in message
news:4ec76c21.174471@news.eternal-september.org...
course.
notch filtering being a common example.
Trevor.
news:4ec76c21.174471@news.eternal-september.org...
Multiple reflections are also common in such instances.On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
r_delaney2001@yahoo.com> 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.
That would be *acoustic feedback* only, There are MANY other types ofFeedback 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.
course.
Or any other method that reduces the loop gain at the feedback frequency,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.
notch filtering being a common example.
Trevor.
D
Don Pearce
Guest
On Sat, 19 Nov 2011 20:22:43 +1100, "Trevor" <trevor@home.net> wrote:
d
No they are not. One cliff, one echo. No choice."Don Pearce" <spam@spam.com> wrote in message
news:4ec76c21.174471@news.eternal-september.org...
On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
r_delaney2001@yahoo.com> 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.
- or even mention - other kinds.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
Again, given the question, no need to complicate the answer.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.
d
D
Dick Pierce
Guest
On Nov 19, 12:12 am, "k...@att.bizzzzzzzzzzzz"
<k...@att.bizzzzzzzzzzzz> wrote:
is meant by "reverb" and "echo" and "feedback."
By "echo" and "reverb," do you mean the acoustical
phenomenon of echo and reverberation? Or do you mean
the analog or digital effects (simulations, if you
will) often labelled "echo" and "reverb"?
"Feedback" is, in some ways, an effect that's in a
different class. But all systems with a connection
between the output and the input are capable of having
feedback, By "feedback," are you talking about when
a system, breaks into self-oscillation, which means
positiive, regenerative feedback?
Wrong. Feedback requires two conditions: first, the delay
must be an integral multiple of a wavelength (or complete
phase rotations: essentially equivalent) and second, the
system must have a power gain equal to or greater than one.
Feedback cannot occur unless both conditions are present.
The requirement of gain in the system is what makes feedback
very different than either echo or reverb.
The notion that feedback requires a delay on the order of
a wavelength is easily shown to be false when one observes
acoustical feedback in amplified PA systems happening at
middle frequencies (several hundred to several thousand
Hertz) where the amplifier and speaker are quite some
distance apart, many dozens of feet, where the corresponding
delay between the two corresponds to many wavelengths.
In such a situation, one very quick cure is to turn the
volume down: this reduces the overall gain of the system
to less than 1, and the regnerative feedback then stops.
There's still feedback, but without the necessary gain,
the system no longer oscillates.
that an echo becomes reverb?
--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+
<k...@att.bizzzzzzzzzzzz> wrote:
Perhaps we might ask the original poster whatRichD <r_delaney2001@yahoo.com
wrote:
On Nov 18, "k...@att.bizzzzzzzzzzzz" <k...@att.bizzzzzzzzzzzz> wrote:
What's the difference between reverb, echo, and feedback?
is meant by "reverb" and "echo" and "feedback."
By "echo" and "reverb," do you mean the acoustical
phenomenon of echo and reverberation? Or do you mean
the analog or digital effects (simulations, if you
will) often labelled "echo" and "reverb"?
"Feedback" is, in some ways, an effect that's in a
different class. But all systems with a connection
between the output and the input are capable of having
feedback, By "feedback," are you talking about when
a system, breaks into self-oscillation, which means
positiive, regenerative feedback?
Aren't they all delay?
Different delay (and decay). If the delay is on the order of a wavelength and
shorter than the decay, it's feedback.
Wrong. Feedback requires two conditions: first, the delay
must be an integral multiple of a wavelength (or complete
phase rotations: essentially equivalent) and second, the
system must have a power gain equal to or greater than one.
Feedback cannot occur unless both conditions are present.
The requirement of gain in the system is what makes feedback
very different than either echo or reverb.
The notion that feedback requires a delay on the order of
a wavelength is easily shown to be false when one observes
acoustical feedback in amplified PA systems happening at
middle frequencies (several hundred to several thousand
Hertz) where the amplifier and speaker are quite some
distance apart, many dozens of feet, where the corresponding
delay between the two corresponds to many wavelengths.
In such a situation, one very quick cure is to turn the
volume down: this reduces the overall gain of the system
to less than 1, and the regnerative feedback then stops.
There's still feedback, but without the necessary gain,
the system no longer oscillates.
So, is there some specific delay value in which you claimGreater than that it's reverb
that an echo becomes reverb?
--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+
Guest
The original post sounded like a homework question.
D
Don Pearce
Guest
On 19 Nov 2011 16:40:38 GMT, sgordon@changethisparttohardbat.com
wrote:
rest for any real physics teacher to have set it.
d
wrote:
I'm not so sure. The feedback part was too far out of kilter with theThe original post sounded like a homework question.
rest for any real physics teacher to have set it.
d
Guest
I was thinking of a recording class in a music department.
In rec.audio.tech Don Pearce <spam@spam.com> wrote:
: On 19 Nov 2011 16:40:38 GMT, sgordon@changethisparttohardbat.com
: wrote:
: >The original post sounded like a homework question.
: I'm not so sure. The feedback part was too far out of kilter with the
: rest for any real physics teacher to have set it.
: d
In rec.audio.tech Don Pearce <spam@spam.com> wrote:
: On 19 Nov 2011 16:40:38 GMT, sgordon@changethisparttohardbat.com
: wrote:
: >The original post sounded like a homework question.
: I'm not so sure. The feedback part was too far out of kilter with the
: rest for any real physics teacher to have set it.
: d
D
Don Pearce
Guest
On 19 Nov 2011 17:26:59 GMT, sgordon@changethisparttohardbat.com
wrote:
d
wrote:
Ah. That probably makes it worse, not better.I was thinking of a recording class in a music department.
In rec.audio.tech Don Pearce <spam@spam.com> wrote:
: On 19 Nov 2011 16:40:38 GMT, sgordon@changethisparttohardbat.com
: wrote:
: >The original post sounded like a homework question.
: I'm not so sure. The feedback part was too far out of kilter with the
: rest for any real physics teacher to have set it.
: d
d
K
krw@att.bizzzzzzzzzzzz
Guest
On Sat, 19 Nov 2011 03:11:23 -0800 (PST), Dick Pierce
<dpierce.cartchunk.org@gmail.com> wrote:
feedback. There is no reason why feedback must be exactly in phase.
certainly can.
obviously a gray area there.
<dpierce.cartchunk.org@gmail.com> wrote:
Disagree.On Nov 19, 12:12 am, "k...@att.bizzzzzzzzzzzz"
k...@att.bizzzzzzzzzzzz> wrote:
RichD <r_delaney2001@yahoo.com
wrote:
On Nov 18, "k...@att.bizzzzzzzzzzzz" <k...@att.bizzzzzzzzzzzz> wrote:
What's the difference between reverb, echo, and feedback?
Perhaps we might ask the original poster what
is meant by "reverb" and "echo" and "feedback."
By "echo" and "reverb," do you mean the acoustical
phenomenon of echo and reverberation? Or do you mean
the analog or digital effects (simulations, if you
will) often labelled "echo" and "reverb"?
"Feedback" is, in some ways, an effect that's in a
different class. But all systems with a connection
between the output and the input are capable of having
feedback, By "feedback," are you talking about when
a system, breaks into self-oscillation, which means
positiive, regenerative feedback?
Aren't they all delay?
Different delay (and decay). If the delay is on the order of a wavelength and
shorter than the decay, it's feedback.
Wrong.
No, it can be sub-wavelength. Half wavelength would essentially be negativeFeedback requires two conditions: first, the delay
must be an integral multiple of a wavelength (or complete
phase rotations: essentially equivalent)
feedback. There is no reason why feedback must be exactly in phase.
To regenerate, sure. There was nothing here about regeneration.and second, the
system must have a power gain equal to or greater than one.
Oscillation cannot occur unless the gain at 360degrees is greater >1. FeedbackFeedback cannot occur unless both conditions are present.
certainly can.
You're conflating "feedback" and "oscillation" (regenerative feedback).The requirement of gain in the system is what makes feedback
very different than either echo or reverb.
Ok, I'll buy that regeneration can occur at > 1 wavelength.The notion that feedback requires a delay on the order of
a wavelength is easily shown to be false when one observes
acoustical feedback in amplified PA systems happening at
middle frequencies (several hundred to several thousand
Hertz) where the amplifier and speaker are quite some
distance apart, many dozens of feet, where the corresponding
delay between the two corresponds to many wavelengths.
Oscillation stops but feedback continuesIn such a situation, one very quick cure is to turn the
volume down: this reduces the overall gain of the system
to less than 1, and the regnerative feedback then stops.
^^^^^^^^^^^^^^^^^^^^
Ok, you've admitted that you're confusing feedback and oscillation.There's still feedback, but without the necessary gain,
the system no longer oscillates.
When you can hear it, but not discern the individual images (echo). There isGreater than that it's reverb
So, is there some specific delay value in which you claim
that an echo becomes reverb?
obviously a gray area there.
K
krw@att.bizzzzzzzzzzzz
Guest
On Sat, 19 Nov 2011 10:16:43 GMT, spam@spam.com (Don Pearce) wrote:
with no opposing wall there will be zero echo.
be an audiophool, by chance?
Two walls of said cliff; multiple echoes. If you're on the edge of the cliffOn Sat, 19 Nov 2011 20:22:43 +1100, "Trevor" <trevor@home.net> wrote:
"Don Pearce" <spam@spam.com> wrote in message
news:4ec76c21.174471@news.eternal-september.org...
On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
r_delaney2001@yahoo.com> 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.
with no opposing wall there will be zero echo.
But you found it necessary to bring up loop gain. Interesting. You wouldn'tFeedback 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.
be an audiophool, by chance?
D
Don Pearce
Guest
On Sat, 19 Nov 2011 12:17:35 -0600, "krw@att.bizzzzzzzzzzzz"
<krw@att.bizzzzzzzzzzzz> wrote:
way of avoiding it if you want to explain what causes the feedback.
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.
d
<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" <trevor@home.net> wrote:
"Don Pearce" <spam@spam.com> wrote in message
news:4ec76c21.174471@news.eternal-september.org...
On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
r_delaney2001@yahoo.com> 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.
Loop gain greater than unity is what causes feedback howl. There is noFeedback 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?
way of avoiding it if you want to explain what causes the feedback.
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.
d
K
Kaz Kylheku
Guest
On 2011-11-19, Don Pearce <spam@spam.com> wrote:
If there is a lot of distance between the speaker and microphone,
you can hear echos rather than howls.
Feedback can be (but does not have to be) used for generating echos and
reverbs in effect units or software.
In digital effects units, feedback is used to make it look like there is more
RAM. Rather than computing all echoes from the original input function (which
requires enough RAM to store a window of sound representing the longest echo
time) the echos are faked by taking the output and feeding a fraction of it
back to the input. The same is done for faking long reverbs.
I have an old Yamaha unit here from 1989 which has only a 700 ms delay,
but the reverb can be cranked to 40 seconds, haha. Any sample you hear beyond
700 ms, related to the original signal, has already been through the digital
mill and is reappearing via feedback. Accordingly, the reverb starts to sound
like crap beyond 2 seconds.
A honestly modeled 40 second reverb would actually have an impulse response
sample of 40 seconds from a nice sounding hall, and use a 40 second window of
the input to do the convolution.
That is positive feedback. Feedback is not always positive.On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
r_delaney2001@yahoo.com> 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.
If you put together many echoes, arriving from different distances
into a jumble that you can't distinguish - that is reverb. You get
that in, say, a large church.
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.
If there is a lot of distance between the speaker and microphone,
you can hear echos rather than howls.
Feedback can be (but does not have to be) used for generating echos and
reverbs in effect units or software.
In digital effects units, feedback is used to make it look like there is more
RAM. Rather than computing all echoes from the original input function (which
requires enough RAM to store a window of sound representing the longest echo
time) the echos are faked by taking the output and feeding a fraction of it
back to the input. The same is done for faking long reverbs.
I have an old Yamaha unit here from 1989 which has only a 700 ms delay,
but the reverb can be cranked to 40 seconds, haha. Any sample you hear beyond
700 ms, related to the original signal, has already been through the digital
mill and is reappearing via feedback. Accordingly, the reverb starts to sound
like crap beyond 2 seconds.
A honestly modeled 40 second reverb would actually have an impulse response
sample of 40 seconds from a nice sounding hall, and use a 40 second window of
the input to do the convolution.
K
krw@att.bizzzzzzzzzzzz
Guest
On Sat, 19 Nov 2011 18:23:36 GMT, spam@spam.com (Don Pearce) wrote:
of an answer speaks volumes).
Zero intelligence.On Sat, 19 Nov 2011 12:17:35 -0600, "krw@att.bizzzzzzzzzzzz"
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" <trevor@home.net> wrote:
"Don Pearce" <spam@spam.com> wrote in message
news:4ec76c21.174471@news.eternal-september.org...
On Fri, 18 Nov 2011 13:51:37 -0800 (PST), RichD
r_delaney2001@yahoo.com> 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.
Wrong. *Regenerative* feedback needs a gain > unity.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.
You can't even keep *your* terms straight. You *must* be an audiophool (lackAnd make no mistake, the feedback the OP was asking about was the loud
howl you get when you turn the PA up too far.
of an answer speaks volumes).