then Sony, Philips, AT and those Chinese ones, they usually are just 16-32 impedance, meaning any portable player or mini amp can drive/power them without problems.
senns (the lower tiers sound bad btw, overhyped) , beyer and grados on the higher tier range usually have 200+ impedance and require decent amps to run, so you have to spend more on the amps. and dont follow that advice of getting the most expensive grados, for one they are open back and not portable, they need a good amp to pair which cost more than the headphone itself, not really logical for your needs.