There is a great function in Aimp player, a bit similiar to Gain but much more simple to use.
I must admit I don't use replay gain - as far as I'm concerned it needs to have all tracks volume level calculated. With my big library (over 90k tracks) and masses of new music I digest it's just too laborious and complicated.
So what's great about normalization?
It normalizes the amplitude (whatever it means
) of a track on the fly. Without any previous volume calculations, that are needed for replay gain, without any additional work, it keeps all played tracks at the same volume level! Just on the fly, by ticking one option on.