Haha! I thought for a minute you were serious. Good joke! You had me fooled there...
Jan
Vibrato (frequency modulation, FM) would cause distortion when for instance the upper sideband(s) have been removed by filtering. The human voice is incapable of producing such FM. Regarding "digitized sounds that could make one (feel) sic" the best example (yet) is DRM as used on shortwave. Even the BBC (one hour daily, 3995 KHz), despite the format allowing up to 12 KHz audio in stereo, actually sounds worse than cassette recordings from the 1970s. Other broadcasters even are using DRM (lower bandwidth) that sounds far worse than the antique AM + interference - best example, AIR at 7550 KHz.
Well - no religion; the forum rules states. You seem delusional in more than one way it seems.
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So why would anybody do that? Some secret equipment know body knows about?
And even if, that's not distortion. That's frequency response roll off.
Jan
I think there is a frequency demodulator missing from the story. A frequency modulator - filter - frequency demodulator chain will always distort to some extent, especially when the frequency deviation is large compared to the modulating frequency and the filter is too narrow. I haven't a clue why this would be relevant to a discussion about vibrato and audio equipment, though.
Nope. "Aridace" is right: band limiting of FM-modulated signal always leads to non-linear distortions, because the spectrum of any FM signal is infinite. But I dont think this is 100% relevant to a problem of spectra squeezing by digital sampling. Voice signal with FM vibrato - yes, expanding the spectra to infinity to both sides (and ADC cuts them), but I think the resulting distortions are pretty small.
The spectra "squeezing" as you call it is non-causal and is not accounted for in any of the references you posted. The same thing as a time invariant process creating in-harmonic distortion, it can't happen.I'm afraid you are going to have to produce some actual data sets, we are talking about maths here.
Where is the FM demodulator located?
Filtering an FM modulate, or anything else for that matter, with a linear time-invariant filter cannot cause non-linear distortions. Only when you FM demodulate a filtered FM modulate, then you get distortions. (Note that an FM demodulator is non-linear: doubling the amplitude of the input signal doesn't double the amplitude of the output signal.)
The mark of FM (which is what vibrato is about) is the absence of AM. Filtering (part of) FM side band energy results in AM so in terms of the human voice, conversion from vibrato to tremolo.
Don't answer that Yes, that's how people used to receive this FM station back in 1919 and the early 1920's:
The first Kurhaus radio-concerts
Tune the receiver such that the RF signal is in the transition band of its filters. The filters then convert FM to AM, which can be demodulated with anything that rectifies. Conversion from FM to AM by filtering is in itself not a non-linear process, though.
Getting back to audio, is the worry that a system with bandwidth limitations could convert the vibrato on the umpteenth harmonic of a soprano's voice into tremolo? That will indeed happen to some extent, but it will happen in any system with a bandwidth limitation. The ears of the listener, for example.
Almost all of your theories should be measurable, untill I see some measurements my money is on BS. Way to many question marks. So much about frequency deviations, when the wow and flutter of vinyl is huge compared to digital.
This is comedy. I just got of the floor. Musician do drugs because of digitized music.
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