If you are facing low bass in your sound you can follow these steps: 

a) Ensure that you are listening to downloaded songs or high quality streams. Note- YouTube Music quality may be lower than expected

 b) Listen to the same song through a different mobile phone

c) Use a different Music Player

d) Ensure volume is set to maximum through Mobile Phone itself

e)  Ensure to use suitable size of ear tips 

Tip: An equalizer (also called an "EQ") is an audio filter that isolates certain frequencies and either boosts them, lowers them, or leaves them unchanged. Equalizers are found on a wide array of mobile devices.

An equalizer will adjust audio output so that certain frequencies are emphasized over others.

Recommend to try a different equalizer setting such as bass boosting