Do the Doppler effect and the redshift indicate a decrease in amplitude and an increase in wavelength?
If so, who is trolling here?
If so, who is trolling here?
N101N - you lost me, but I am trying to understand your points. Do you have evidence that sound absorption through felt or foam decreases the magnitude AND changes the wavelength / frequency ? Or am I misunderstanding your point? I have never measured this phenomenon, but I am always open to new ideas and concepts.
Amplification is to raise vibrational velocity, thereby increasing amplitude, frequency, current and a bunch of other parameters. The opposite of amplification is attenuation. Damping and filtering are methods of achieving attenuation.
No and yes, respectively.
If you put a ringing tuning fork under a blanket, does it resonate at a different note?
Why no and yes? Anything that moves must give up kinetic energy and must lose velocity increasingly with Distance. Let`s call it natural attenuation. Damping is a methodical attenuation.
Amplitude and wavelength are inversely related. Planck's equation says: E = hc/λ where λ = wavelength
The sinusoidal waveform represents a nonexistent physical state.
Amplitude and wavelength are inversely related. Planck's equation says: E = hc/λ where λ = wavelength
The sinusoidal waveform represents a nonexistent physical state.
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Don't bother, we now know your omnipotent knowledge expires after mere 59 minutes. 🙂
on topic: with regards to felt on the baffle, it's my understanding as well the felt creates a "virtual" edge at the boundary and hence birth of sound wave diffraction, and that the strength of diffraction is dependent on how well the felt absorbs.
edit: come to think one interesting thing to test out is to place a felt cut after the Fibonacci spiral on a square baffle.
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A sound wave is propagating mechanical energy that is harmonically exchanging the kinetic energy of the moving mass and the potential energy of compressing the medium.
The air squeezing through small holes creates large velocity gradients and significant viscous stresses which the moving air works against transferring kinetic energy to heat.
The presence of the solid material adds heat capacity and moves the largely adiabatic compression process in air alone towards a more isothermal one (the main reason for the apparent increase in volume of a sealed speaker with light-to-medium stuffing).
The kinetic energy can also changed by the solid material moving with the air which varies significantly with the type of material with short fluffy fibres tending to move more than foam glued to a wall.
These additional effects compared to air alone tend to vary strongly with frequency. The frequency doesn't change but the speed of sound through the material and the corresponding wavelength does. A brief google for sound in porous material can provide examples of what can be achieved/expected.
This discussion is interesting, but it sounds more or less like discovering the Hot Water again (or the wheel if you prefer).
The late John Dunlavy did a lot of research and practical at that ( he was a major speaker manufacturer with Duntech in South Australia and then DAL in his native USA) on the topic.
For anyone who doesn't know, all his speakers employed a lot of felt on their front baffles and a lot of other manufacturers copied John's effort without ever acknowledging his input.
So do not want to sound arrogant and offend anyone, especially on NYE, but please study his work first and then argue as much as you would like.
As far as I am concerned all the work has been done long time ago and all the knowledge is there.
One only needs to be willing to find it.
The late John Dunlavy did a lot of research and practical at that ( he was a major speaker manufacturer with Duntech in South Australia and then DAL in his native USA) on the topic.
For anyone who doesn't know, all his speakers employed a lot of felt on their front baffles and a lot of other manufacturers copied John's effort without ever acknowledging his input.
So do not want to sound arrogant and offend anyone, especially on NYE, but please study his work first and then argue as much as you would like.
As far as I am concerned all the work has been done long time ago and all the knowledge is there.
One only needs to be willing to find it.