The combination of psychophysiological and psychometric methods provides reliable measurements of affective user experience (UX). Understanding the nature of affective UX in interactive entertainment, especially with a focus on sonic stimuli, is an ongoing research challenge. In the empirical study reported here, participants played a fast-paced, immersive first-person shooter (FPS) game modification, in which sound (on/off) and music (on/off) were manipulated, while psychophysiological recordings of electrodermal activity (EDA) and facial muscle activity (EMG) were recorded in addition to a Game Experience Questionnaire (GEQ). Results indicate no main or interaction effects of sound or music on EMG and EDA. However, a significant main effect of sound on all GEQ dimensions (immersion, tension, competence, flow, negative affect, positive affect, and challenge) was found. In addition, an interaction effect of sound and music on GEQ dimension tension and flow indicates an important relationship of sound and music for gameplay experience. Additionally, we report the results of a correlation between GEQ dimensions and EMG/EDA activity. We conclude subjective measures could advance our understanding of sonic UX in digital games, while affective tonic (i.e., long-term psychophysiological) measures of sonic UX in digital games did not yield statistically significant results. One approach for future affective psychophysiological measures of sonic UX could be experiments investigating phasic (i.e., event-related) psychophysiological measures of sonic gameplay elements in digital games. This could improve our general understanding of sonic UX beyond affective gaming evaluation.