understanding sub frequencies in your mix
figured out that if you throw any distortion unit on your LF bus / master and extreme smash the signal, then those added harmonics will make all your low freq information "visible" even without a good speakers or in a crappy room
i use it a lot to polish kick's sine or arranging the sub bass + kick
you basically mix levels / eq all of those low freq elements together while that crazy distortion is applied and then remove the distortion
sometimes a big profit !