[grapefruit]

I'm a high school student who's just gotten into audiophile equipment and I was wondering exactly how different headphones differ from each other, along with what makes the ideal setup. This is purely out of boredom and curiosity.  So here goes:
 
1.  What properties make for an ideal sound driver?  masslessness and no resonance?

2.  What separates a company's best headphone of a similar design to their worst?  Take sennheiser for example with their 5XX and 6XX line.  Is it just driver weight and material?

3.What the are the diaphrams made from in dynamic drivers and BA drivers?  Do BA drivers even have diaphragms?
 
4. What does impedance do,  eliminate background static?
 
5. How is soundstage created?  Is it from slight variations in the phase of each channel?
 
6. I know that our perception of frequencies from 20-20000 hz is non-linear, do linear headphones compensate so that our perception of the frequencies is linear, or do headphones simply put out a linear frequency response which we perceive as non-linear?
 
 
Just wondering because it seems like each company is trying to get the perfect sound, but they all go about doing it differently.  I have no idea how most audiophile stuff works, so any type of answer is appreciated.
 
Thanks,
Mike
 
 

 

[Shike]

1) Depends on the type of driver.  The traditional dynamic transducer is to be rigid, low mass, and able to move enough air to produce desired frequencies.
 
2) Various things.  Some headphones are marked different but virtually identical.  Some use different materials, drivers, enclosures, etc.  This requires research from model to model.
 
3) Dynamics vary, but a rigid mylar is quite popular.  BA use a vibrating metal pole/similar iirc: http://wiki.faust3d.com/wiki/index.php?title=Balanced_Armature_Driver_Principle
 
4) Impedance is the resistance presented to a an amplifier at a given frequency, it in of itself isn't inherently useful except to match to proper amps with consideration of damping factor/power requirements off the top of my head.
 
5) Perceived space between left/right, there's multiple ways to create it.
 
6) Many equalize for HRTF, so the headphone raw frequency response is not flat in most cases.

 

[Mauricio]

4.)  In general, impedance is the opposition to the flow of current in the presence of a electric potential difference (aka voltage) in a circuit.  Impendance is a function of signal frequency.
 
5.)  Actually the human auditory apparatus relies on just two mechanisms for determining location.  One mechanism is based on the difference in time that it takes sound to reach the right and the left ear.  The second mechanism is based on the difference in magnitude of the sound reaching the right and the left ear.  Where each mechanism predominates depends on the frequency of the signal.