It's frustrating how Spotify in mobile cannot be louder than it is even at maximum volume with or without equalizer and normalization. It gets more useless in the middle of an extreme workout, unless you have powerful headphones that have an independent volume booster.
Can the Spotify Team please add a Preamplifier (or Preamp) function in the app? It is the one that has the + / - dB or -10—0—+10 slider in some music players. That would be a wonderful addition. If it's possible for other apps to have one, I believe the Spotify software developers and engineers can be as intelligent or even better.
I'd like to stick to Spotify for a long time, so please consider this as an ULTIMATELY CRUCIAL suggestion. Thank you.
The example below is from the N7Player app: