I notice that on a some of the headphone reviews, certain headphones are only recommended with certain EQ settings. I know it is fairly straight forward to EQ using software in Windows. However for "on the go" listening e.g when using Bose QC35 II on the go with an iPhone - is it possible/practical to EQ to the level recommended in Amir's reviews for "on the go" listening? I know Spotify has built in equaliser on iPhone - would this be sufficient for equalisation or is it too basic to adjust to the level of detail indicated in Amirs reviews generally?