I think you should level your master channel to some-6db when you start producing then in the mastering apply the remaining db that are missing to reach an optimum volume, always taking into account some reference track to get a clear point of view on the ideal volume you want to achieve.
  Usually I do it that way because I learned it from engineers who give this kind of advice and have a lot of time in the music industry doing mixing and mastering.
 

This is my new track. I hope that they can really listen and imagine a little what describes the sound. Thanks to all

You can download it for free

Have you thought that could be several bass lines coupled with saturation and compression so that they sound flat

How do you control the gap?

To start I want to say that I used 3 layers of the same supersaw and panning for larger image stereo. First take a sample of the supersaw and shipping to a channel of the mixer all left and then another sent exclusively to the right and leave the principal in the Center already with this is this expanding more spectrum estreo, only is playing with frequencies in the EQ so that it is as you want it to sound the supersaw.

Also usually use tools like which brings the fl studio both the stereo shaper and the fruity stereo enhancer or the famous stereo image S1 waves plugins is very good to extend the area stereo otherwise serious export in wav every sound in this case supersaw and pass them through the imaging tool stereo iZotope ozone 5 6 or 7 

Try mixing layers of sharp plucks and working sound on EQ and you're listening to your sound to see if it is equal. Luck