Good suggestion Scott !
A pretty important issue is the 'impedance' of the headphones. (almost the same as 'resistance')
Some have 30 Ohms, 60, 120, 200 or even 600 or higher !
The impedance is not an indication for the quality..... just different types.
You could try to find out the best sounding impedance ? (Scott : your impedance ?)

Roel