absolutely.Not in a multidriver system though. There we would have acoustical mixing and no FM but 2 pure tones.
How big would the amplitude difference need to be before it becomes audible (assuming linear transducer)
no idea
absolutely.Not in a multidriver system though. There we would have acoustical mixing and no FM but 2 pure tones.
How big would the amplitude difference need to be before it becomes audible (assuming linear transducer)
One is totally in the electrical domain.
This example is half electrical domain, modulating the physical domain with respect to the actual position of the sound emanating source (the vc and its acceleration characteristics) in real time.
Not in a multidriver system though.
How big would the amplitude difference need to be before it becomes audible (assuming linear transducer)
I think @March Audio is saying FM modulation of an electrical signal is essentially the same as Doppler modulation of an audio (electromechanical driver) signal.
I think @March Audio is saying FM modulation of an electrical signal is essentially the same as Doppler modulation of an audio (electromechanical driver) signal. Look at the equations posted by @SIY in post #7 (https://www.audiosciencereview.com/...sense-edit-it-actually-does.8994/#post-228911 ) and compare to e.g. Wikipedia's (somewhat long and confusing) description of FM modulation https://en.wikipedia.org/wiki/Frequency_modulation (I have a much better description in my old RF books but not with me at the moment.) Similar, and similar in spectral results, but not quite the same though you could mash them together (I have a vague memory of being forced to do that in a RADAR class ages ago but have mercifully forgotten the details).
They are closer in this context of speaker modulation than the basic equations SIY showed as the velocity is time-varying with the signal. I think. It's early yet here, and my test just finished, so back to work.
HTH - Don
Intermod shows as bands at f1-f2, f1+f2, and combinations of nf1+/-mf2, where n and m are integers.
Doppler will show frequency shift that's velocity dependent. So if the the bands don't broaden and the broadening isn't a function of the lower frequency amplitude, it's not Doppler.
As for the speakers, the 6k tone alone looked like this (left speaker only):
View attachment 33556
And 80 hz added:
View attachment 33555
It's interesting, because the 6k alone already produces a sideband. Maybe it's due to the tweeter itself or the internal amplifier, I don't know how distortion free It should be. And when I add the 80 hz tone, the existing sideband stays pretty much the same, and it adds another, higher one. It's about the same level as the one present in the Lcd2c. Not sure what to make of this. Could be the microphone itself is distorting or some other effect I missed. At any case, the Clears show significantly more distortion (whether doppler or IMD) than the rest, which is how it sounded like to my ear.
So I gather you've heard it and don't like it? I've only ever seen one AFAIK and it was pretty impressive but I did not have much time with it.
Whatever, except for the relation to a fan, not relevant to this thread.
My question about this phenomenon comes from the fact that when multiple simple acoustic sources are simultaneously emitting sound, the sources combine into a complex (summed) waveform. When a listener hears this complex waveform, the acoustic processing area of the brain 'decomposes' this complex waveform back into a perceived set of simple sources once again (similar to a Fourier decomposition, but done using the neuronal processing within the auditory center of the brain). Therefore a speaker driver must follow this complex waveform precisely, so that the emitted pressure wave is a faithful copy of the complex (superimposed) waveform that impinged upon the recording media in the first place. As long as the driver can follow the complex waveform, the brain should be able to decompose the complex signal back into the perception of a set of simple sources once again. In this understanding, the "modulation" of one of the components of the summed waveform other components of the summed waveform is supposed to happen - since this is what produces the complex waveform in the first place. Is this not correct?and think of any signal being frequency modulated by a sine wave. does it not do the same thing? Sorry I am probably having a dumb day
so with the speaker the higher frequency wave is being compressed and rarefied by the lower frequency signal. Its frequency is going up and down.
For example, here is the sum of four simple (sinusoidal) sources. This just seems like a complex waveform that would have to be traced out by the loudspeaker driver, and then 'decomposed' back into simple sources by the listener.My question about this phenomenon comes from the fact that when multiple simple acoustic sources are simultaneously emitting sound, the sources combine into a complex (summed) waveform. When a listener hears this complex waveform, the acoustic processing area of the brain 'decomposes' this complex waveform back into a perceived set of simple sources once again (similar to a Fourier decomposition, but done using the neuronal processing within the auditory center of the brain). Therefore a speaker driver must follow this complex waveform precisely, so that the emitted pressure wave is a faithful copy of the complex (superimposed) waveform that impinged upon the recording media in the first place. As long as the driver can follow the complex waveform, the brain should be able to decompose the complex signal back into the perception of a set of simple sources once again. In this understanding, the "modulation" of one of the components of the summed waveform other components of the summed waveform is supposed to happen - since this is what produces the complex waveform in the first place. Is this not correct?
How is the brain supposed to decompose a signal that has been distorted by a speaker? How is it going to compensate for the distortion if it doesn't know the nature and amount of distortion? How is it even going know the sound is not as intented?As long as the driver can follow the complex waveform, the brain should be able to decompose the complex signal