Double-click on the "Audacity" logo on your desktop. If you don't have a desktop shortcut, click "Start," "Programs," and select "Audacity" from the list. It may take a few seconds for the program to load fully.
Click "File" and select "Open Recent." From the drop-down menu, select the song to which you want to apply a bass drop.
Identify the part of the song where you want to put the bass drop. Typically, the bass drop comes between the middle and the fade out. Scroll the track along by pressing "Play" and then pressing "Pause" when you get to the point you'd like to drop the bass.
Click on the bass channel to highlight it. Click "Control," and select "Zoom" by clicking the magnifying glass icon. This enlarges the wave form of the bass track and makes it easier to make accurate edits. The wave form is a series of tall peaks, small peaks and flat lines that indicate high volume, low volume and silence, respectively. The peaks are arranged inside grids that represent the measures and beats of the track.
Click "Edit," and select the "Scissor" tool. Click the scissor tool on the bass track where you want the bass drop out to start. Press "Play" and let the track roll along. Press "Pause" when you get to the point you want the bass drop out to end, which typically is at end of a measure cycle. For example, the drop out would end on the last note in measure eight of an eight measure cycle.
Click the cursor on the bass track at your selected point to create the trim point. The audio between the two cut points is now a separate track from the rest of the bass line. You either can delete it entirely or drag it to a muted track. If you want to keep the audio, drag it to a muted track. If you definitely don't want to use it in another part of the song and want to keep the interface tidy, delete it.
Click on the drum audio channel to highlight it. Drag the navigation bar back to the the measure just before the bass kicks in. Use the "Scissor" tool to delete the last beat of the drum track. The last beat of the measure is the tall peak farthest to the right in that grid box. By deleting the last beat, you create a brief silence in the bass section. This adds impact when the bass and drums kick back in after the drop.