Both may have quite a bit of low end, and when you try to mix them together, they overlap causing the low end to sound blurry or distortion. You have two bass sounds – bassline and big fat lead synth in this case. With it, you can cut the unwanted frequencies or boost the ones that need to be more present. Proper use of equalizer can indeed make your songs sound significantly better. Equalization in audio production is the process of adjusting the volume of specific audio frequencies to obtain a balanced frequency spectrum.
