To me that's just a bunch of random words, I'm probably thick, can you explain what you mean in words I might be able to understand?
Sanctimonious prat. Some of my favourite tracks were probably recorded on cassette, or the 60s equivalent thereof. And that’s perfectly fine. I want to hear every last bit of hiss, exactly what was recorded. I don’t pretend to know better than the artist.
That goblty-goop translates to an amplifier that is able to slew it's output to reproduce the complex composition of many harmonic rich instruments all at once.
That was amazing to me when I first studied amps, how in the world does one path to the speaker make all those different vibrations at once ? LOL
That was amazing to me when I first studied amps, how in the world does one path to the speaker make all those different vibrations at once ? LOL
Much the same as a single mouth produces all those rich frequencies all at once ;-)
Fourier showed us how that is possible. He showed that even with a lot of simultaneous sounds, frequencies, if you look at it in the time domain, at any one time there is only one 'level' in the signal that needs to be reproduced.
This is typically the hardest thing to comprehend by the 'fourier deniers' (not saying you are one).
Jan
Fourier showed us how that is possible. He showed that even with a lot of simultaneous sounds, frequencies, if you look at it in the time domain, at any one time there is only one 'level' in the signal that needs to be reproduced.
This is typically the hardest thing to comprehend by the 'fourier deniers' (not saying you are one).
Jan
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I love FFT. I'm simply too worn out to do much with it. And yes THAT is the explanation, but how about the person in fascination finding this out too soon to enjoy the find ?
But still that does point to the importance of an amp's slewing ability. And it's ability to eat back EMF without mutilating it's feedback system. LOL
But still that does point to the importance of an amp's slewing ability. And it's ability to eat back EMF without mutilating it's feedback system. LOL
Slewing ability is a dead horse. Whatever the multitude of frequencies and signals from the orchestra, in the end what comes out of the mic preamp and the mixing console is band-limited. So if you can slew the max signal at that highest freq, you're done.
And an amp doesn't know anything about back EMF. It appears to the amp as a change in load and the amp will sink or source whatever is necessary to maintain its 'commanded' Vout. The back EMF may cause the load to appear inductive, capacitive and even as a negative impedance, like a positive Vout requiring current sinking.
As far as the feedback is concerned, it just divides down Vout and the result and the Vin determine the drive voltage for the amp itself. That system has no concept of back EMF or whatever.
Many of these issues stem from people that 'anthropomorphize' amplifiers, i.e. seeing them as a person almost that is troubled by everything that is going on simultaneously. But that's just our limited ability of comprehension.
Jan
I was thinking intertia of the cone could try to push current through both the global feedback and the emitter feedback resistor in the output. The amp voltage suddenly drops by signal, then the voice coil generates the back current and injects it into the feedback path as it is returning to neutral.
I don't see anything irrational about that consideration. I suppose these modern semiconductor output stages win by the brute force and ignorance of being an ultra low impedance current source.
I don't see anything irrational about that consideration. I suppose these modern semiconductor output stages win by the brute force and ignorance of being an ultra low impedance current source.
No, nothing irrational, but there may be a better way to look at it.
The cone wouldn't 'push' anything into the feedback path. The feedback is just a resistive divider, dividing down whatever is at the amp output end. The current into the feedback path is just Vout/Rfeedback. Assuming the inverting input is very high impedance, Rfeedback is the sum of the two Rs in the divider.
All straight ohms' law, no need to invoke cones that push or amps that eat ;-)
Actually, if the amp has very low Zout, you would see very little or no change in Vout when the cone resonates or otherwise generates EMF. So then there would be very little or no change in the current through the feedback divider.
If that low amp Zout is generated by high feedback, what you would see is a change in the internal drive voltage to the drivers and output devices to keep that Vout from changing by sinking or sourcing more or less current, as required. But as we know that is how feedback works anyway.
Jan
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Mother Nature is always willing to change something for something else. But never a free lunch ;-)
Jan
Jan
Haha, nice. I always thought NFB was more of a philosophical concept. I tried explaining to a tutor when handed a feedback form that I only give negative feedback because it was the only positive thing to do so I don't bother because it tends to be ignored because it's considered negative
You're bad!
But seriously, it is true. Nature will change things for you but not give anything out for free. That is the explanation why E=MC^2 works but a perpetual machine does not.
Jan
But seriously, it is true. Nature will change things for you but not give anything out for free. That is the explanation why E=MC^2 works but a perpetual machine does not.
Jan
"Rien ne se perd, rien ne se crée, tout se transforme."
Laurent de Lavoisier (1743-1794)
Nothing is created, nothing is lost, all is transformed.
Laurent de Lavoisier (1743-1794)
Nothing is created, nothing is lost, all is transformed.
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If you want to see RTEP at work. Take two (op) amps and connect a resistor between the outputs and apply two different signals to the inputs. It is like magic how each output still maintains the correct voltage.
What is RTEP ?
I guess your point about a resistor in between two op amp outputs is to show the very low output impedance from negative feed back.
No significant crosstalk can occur with extremely low Zout versus the resistor value in between.
I guess your point about a resistor in between two op amp outputs is to show the very low output impedance from negative feed back.
No significant crosstalk can occur with extremely low Zout versus the resistor value in between.
Real-Time Error Prevention, formally known as Negative FeedBack.
Why Let an Amplifier Sound Good when You can Force it to?
Why Let an Amplifier Sound Good when You can Force it to?
Why Let an Amplifier Sound Good when You can Force it to?
Why Let an Amplifier Sound Good when You can Force it to?
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Maybe you listen at a lower volume than was used during mastering. As Fletcher and Munson found out in 1933, you hear less bass at low volumes.
There is a fullness a live band has that I have never heard at living room levels. I think for studio work the 200hz to 500hz band gets scooped a bit for a cleaner sort of sound. Fat is actually a bit accented in that freq band to "punch through the mix". Such as the guitar in live performances has that sound similar to switching the tweeter off and limiting bandwidth.
I have never heard playback that could fool me into thinking I was listening to a live band. Close but not quite.
I have never heard playback that could fool me into thinking I was listening to a live band. Close but not quite.
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