[Stereo Skunk]

there is a 'state space' for headphones and amplifiers.

for a given headphone I can only think of it varying in driver excursion. fully flexed one way, dead center. fully flexed the other way and everything in between. My question is how does this change the impedance, inductance and capacitance of the headphone? What is 'worst case scenario'? Then you have different types of headphones varying in nominal impedance and sensitivity. I imagine hardest tod rive would be low sensitivity and either very low or very high impedance.

What i am trying to understand better is when a headphone "demands" the most of an amplifier, and in what way.

likewise, amplifiers have a state space defined by power, load impedance, frequency. Of course typical distortion specs (thd,imd,noise) will vary across these. I'm not as interested in these, but rather power, current and voltage bandwidth across these varying parameters, and how these degrade a DC signal into the rectified AC from which it is made.

What I'm asking is which amplifier has the beefiest power supply, and does this necessarily mean high power? (couldn't an amplifier have an over-sized capacitor bank? and would this be desirable?)

 

[71 dB]

For accurate sound headphones need many things to be right, but one that is relevant here is damping. Damping can be mechanical or electrical or combination of both. High mechanical damping means lower efficiency, but there is no need for ellectrical damping, so the output impedance of the headphone amp can be large. Low mechanical damping means higher efficiency, but also calls for high electrical damping meaning the output impedance of the headphone amp must be low. Looking at heaphone measurements one have deduct how much mechanical damping there is: Typically high mechanical damping leads to flat impedance curve especially at bass frequencies where the resonance frequency of the drive is. Likewise low mechanical damping leads to a impedance curve that has a huge "bump" at the driver resonance frequency (typically around 70-100 Hz).

Headphone impedance dictates which is more important: Voltage reserves or current reserves. High impedance means voltage reserves must be good. Low impedance calls for good current reserves. What are low and high impedances for headphones? I'd say, under 50 Ω is low and over 200 Ω is high.

Of course bigger capacitor bank helps, but capacitors aren't free. Manufacturers cut corners whenever they can to save a nickle. If you leave out a couple of capasitors and save $0.20 per unit, ten thousand units manufactured saves you $2,000. For a small audiophile company manufacturing only headphone amps that can be a significant amount of money helping to keep the lights on.

 

[Stereo Skunk]

This is very interesting.

In a mechanically damped design, the amplifier has to push it very hard, but it seems like it would decay very quickly.

On the other hand, in driver designs where the mass is much lighter than the air displaced, it seems like there would be drag-damping. In such a scenario, the amp really is pushing the air.

I can't tell which is 'better' from a thought experiment perspective. Audibly? I'm sure both can be tuned to sound great. I feel like a near mass-less, high surface area driver, with high damping ratio in the powerful amplifier would be ideal. Furthermore, to be easier on the amp I would think a higher impedance load would be better to err on, because I think voltage is "easier" than current (hence the capacitor question). One could oversize a cap bank for a high voltage application.

So what is high impedance/voltage, near massless, high surface area? estats?