changing driver in Peltor headphones?

What matters are the impedance: 100 ohms and the max power handling: 100mW in this case. Beyond that it also has to physically fit which is one of those jokes about standards.

You won't use a crossover in headphones. I can be done, but then there is an issue of directionality. I'm sure some high-end, mega-expensive brand with huge can space for the drivers and maybe even a relief port for extra bass.

Headphone speakers don't have as much to deal with as other ones as they are so close to our ears. 

@marcdraco Hello, 

Can I ask you a question? If I were to switch speaker drives in a pair headphones but keep everything like the original wires and circuit board, would there be issues in the audio? Or would I have to find an OEM replacement for the original? I'm asking because Im looking to change the speakers in my old headphones.

Welcome Justin,

"Normal" headphones, that is without a Bluetooth driver it's really not important, so long as you get headphone drivers - also be wary of the space you have to work with as not all speakers are the exact same dimensions, and may have specific fittings.

For a Bluetooth (or similar) headset you need to consider above plus you should attempt to match the driver's impedance. Measured DC impedance is fine - headphone speakers have much higher impedance normally, >250 ohms, but a speaker destined for its own amp, that's more difficult because then you really have to match the impedance - which is usually written on the magnet housing.

It's not that other drivers won't work, they almost certainly will, but they may cause the amp to distort, for example.

* If you are measuring the resistance (DC impedance) of the coil try to do it quickly as the measurement could, potentially, damage the coil by overheating it. Modern meters shouldn't be an issue but you can't be too careful.