Physics of Sound and the middle ear? Once sound waves reach the eardrum, the eardrum moves back and forth and transmits those waves/pulses to three bones that serve to transmit and amplify the pulses to another "drum" in the inner ear.
The diagram I linked below shows how that amplification occurs, due to the relationship between Pressure  = Force x Surface Area.
I don't understand how F1 and F2 are related? I think it has to do with the two pivot points but I am confused as to how to work out the relationship.

I also have trouble understanding how if these bones become more rigid, then why that would only affect the amplification but not the frequency of the sound?
Doesn't frequency get translated by the bones as well? so if the three become more immobilized/stiffer, the frequency of pitches would go up? (more stiff higher frequency). On this point I am just trying to make an educated guess

 A: You are right to some extent, the properties of bones has some small effect on the frequency. Not only that but some sound waves even get transmitted via out skull bones. 
The point is decoding what comes through and understanding the sounds happens in the brain, which has already anticipated and adjusted to the interference of our bones and acoustics of our ears. Plainly said It is the brain that understand what you hearing for example is the sound of passing bus in the street while still allowing you to hear what your friend walking next to is saying
By looking at the diagrams you have one realizes there has to be a great leap of faith to arrive at the quantities and proportions the book states. The bones are leaning and pushing against each other in very complex surfaces and in off-center axis.
To illustrate how important the role of brain is in hearing, I have to wear hearing aids and as opposed to intuition when I don't wear them I hear some low frequencies even louder, to the point of being painful. My guess is my brain in trying to compensate for lack of understanding amplifies the band of spectrum of total sound it hears, beyond comfortable level! 
