A standard modern DnB sub-bass is not one synth, it is two or three layered together. The technique is simple, the result is the difference between a track that hits in the club and one that vanishes on the dancefloor.

The three layers

Layer 1: a clean sine wave at the fundamental frequency (around 40-60 Hz). Provides the physical weight you feel rather than hear. Layer 2: a filtered saw wave one octave up. Provides the audible bass note you actually hear on small speakers. Layer 3: a slightly distorted version of layer 2 with the lows cut. Provides the harmonic content that translates on phone speakers and laptops.

Why it works

Each layer covers a different listening environment. Club soundsystem hears layer 1. Decent headphones hear layer 2. Phone speakers hear layer 3. The track sounds heavy everywhere because each environment has the right frequency content.