A bass line can disappear into the background as a general foundation. Follow it deliberately, however, and a distinct movement emerges: notes begin, sustain, change and leave gaps. That movement can coincide with drums while also clarifying harmonic changes. Listening to bass therefore involves more than making the lowest frequencies as loud as possible.
Find the line first
Choose a recording with an identifiable lower part and keep playback at a comfortable level. Try quietly humming its sequence or tracing its rhythm with a finger. If that proves difficult, find a less crowded passage. Turning up a bass control increases low-frequency energy but does not automatically separate musical roles.
Do not immediately identify every short low impact as a bass note. Kick drum and bass instrument may both draw attention in the lower range while developing differently. Listen for a discernible pitch continuing after the onset. This distinction can remain difficult in heavily processed recordings; a cautious description is then better than a confident label.
Hear the relationship with drums
Ableton's introduction describes bass lines as combining harmonic support with rhythmic patterns that can relate to or contrast with drums. First listen for coinciding entrances. Then find places where the bass continues between drum hits or deliberately leaves a gap.
An invented pattern makes the distinction clear. A bass note only on the first beat of each group feels different from several short responses between beats, even if the pitch stays the same. Placement alone changes whether the accompaniment pushes forward or leaves space. Rhythmic movement is therefore not equivalent to frequent changes of pitch.
Notice harmonic transitions
Find a point where the accompaniment changes harmonic colour. Does the bass move with it, remain in place or begin moving slightly earlier? You do not need to name the chords. Describing a low note that continues while something changes above it is already a meaningful observation.
Finally, hear the passage once while attending to the voice and once while attending to the bass. A familiar chorus may become less uniform than it previously seemed. Record a specific transition rather than simply judging the bass good. This makes the lower line audible as part of a musical exchange, instead of treating it only as a strength or weakness of the playback system. It also gives you a concrete point of comparison when hearing another performance of the same piece.