HOW HUMAN HEAR SUB-BASS?

When you are designing (or mixing) audio, you have to keep in mind the final consumer. Who's going to listen to this song? In what environment, what device, what file, etc. This is even more important when you are mixing bass-heavy track or genre.

Humans can hear from approx 20Hz up to 20kHz. The majority of the useful spectrum is somewhere along 40Hz to 12kHz. This is what the early days of MP3 were based on. Just eliminate sound on the edges of our hearing.

Now that we have fast connections and lossless files this is no longer an issue. That opens the door to a great sounding mix on streaming services. 

If your mix is likely to be transferred via the internet and listened to on headphones, you have to be careful with how it sounds. It's even more important to stay balanced than ever before. People buy colored headphones to their liking. So forcing them to listen to too much bass because you think the mix needs it is not a favor to anyone. If they like bass, they'll have headphones with excellent bass reproduction. And vice versa. If they want the detailed sound, they'll have some precise audiophiles like headphones. Both will color your mix to the user's liking. So no need for you to do that. This is of great importance to understand; if you mix it balanced, it will sound good to any consumer on their preferred system. Period.

So to keep this in mind. The majority of music is played on headphones, so it makes sense to mix on headphones due to leveling, panning, reverbs, etc., that sound different on headphones compared to speakers in a room. Another point is to mix on balanced headphones so that you can make a balanced mix. There are a few choices out there. Very popular is HD650 and DT770, but M50 is close behind.