Selective attention is a dynamic process that rapidly shifts processing resources to information that is most relevant to our goals. Although individuals often show spatial biases in attention, these biases can be modified by both long-term factors, such as musical training, or by momentary changes in the auditory context. The present study used a visual search task to examine the influence of these factors on spatial attention biases while increasing demands on selective attention. Experiment 1 examined the effects of musical experience on baseline spatial selective attention biases during search. Individuals with little musical experience showed a typical leftward response bias that became stronger as the number of distractors increased. However, those with more musical experience showed similar responses to targets on the left and right sides, indicating an attenuation of the typical leftward spatial attention bias. Experiment 2 examined whether the addition of low- and high-frequency tones dynamically influenced participants’ spatial attention biases during visual search. Participants showed increased orienting to and scanning of left-side distractor locations in response to low-frequency tones regardless of musical experience. The present results demonstrate that spatial attention biases are dynamic and can be shaped by both long-term experiences and momentary contextual effects.