Eiher you are moving enough air or you are not. If you are not, either the cone needs to be bigger, or it needs to throw farther, or you need something to channel the sound (like a horn).
If you are moving enough air, either you are reproducing the sound correctly or you are not. If you are not (because you are db down) then equalization is an option (though it would take a custom equalizer to hope to bring to flat).
If you are moving enough air, and the sound is being reproduced correctly, then the issue is either the source material, or the volume nob.