Launch Reason by clicking the three-pronged icon. Allow the default song to load, creating a hardware input device, a mixer and a MIDI arrange window. Click the "View" menu at the top of the screen and select "Tool Window," causing the selection of available instruments to appear.
Double-click on one of the emulated analog synthesizers. Subtractor, Malstrom or Thor. All are suitable for creating Hip-Hop basslines, but different ones will be suitable for different sub-genres. Subtractor is best for 80s-style Old-School sounds, Malstrom works well for 90s "Glitch-Hop" or "G-Funk," and Thor is most suitable for very modern "Techno-hop" tones. The Subtractor is the simplest and most accessible layout, so start there if you aren't familiar with the controls.
Create a Subtractor synth by double-clicking the image of it in the Tool Window. This will also create a MIDI sequencer track and assign it to the Subtractor. Click on the folder icon next to the patch display, and navigate to the "Bass" folder. Double-click on the patch named "Chronic Bass." This is simple bass sound, ideal for editing. Its possible to create patches from scratch once you become more adept with the controls, but to begin with, using a preset as a starting off point will save a great deal of time.
Set the "L" and "R" locators in the MIDI sequencer to a 4-bar loop. Click the "Loop ON/OFF" button on the transport bar to turn on Loop mode. Hit the "Record" button on the transport bar and play a 4-bar phrase using a MIDI controller, or by drawing notes in the MIDI sequencer with the pen tool. It doesn't need to be perfect right away, the idea is to generate a constant sound, freeing your hands to adjust the synthesizer controls.
Adjust the filter slider in the upper right corner of the Subtractor to shift the cut off frequency of the filter; this will alter the tone of the sound from bass to treble. Click the up and down arrows next to the waveform images in the top center of the control panel to select different waveforms, this will alter the texture of the bass sound, from smooth to jagged and robotic. The "Amp Envelope" controls allow the adjustment of the Attack, sustain, decay and release of each note, with each labeled slider. There are identical envelope sliders for controlling the same properties for the filter and modulation effects.