Music is a critical atmospheric element retailers can leverage to shape consumer behavior. Music tempo in particular has been shown to impact consumer behavior, with initial studies suggesting slower music to be especially effective in boosting turnover across consumers. We propose that slower-tempo music (vs. faster-tempo) increases sales, particularly for loyal customers, who typically visit stores more often and are thus more exposed to the music played. We conducted the largest field experiment on music tempo to date, involving 140 stores in a large retail chain. Although we found no significant impact of tempo on overall turnover, slow-tempo music significantly increased sales among members of the retailer’s loyalty program. These findings offer nuanced insights into the interplay between music and consumer loyalty, and call for a better understanding of how different consumer groups are impacted by in-store music. In-store music is a powerful yet often underleveraged tool retailers can use to shape consumer behavior. While earlier studies suggested that slower-tempo music boosts overall sales, our large-scale field experiment—spanning 140 stores in a national retail chain—shows a more targeted effect. In our research, we found that slow music led to a small increase in sales, but only among loyal customers, such as loyalty program members, who typically visit more frequently, explore more products, and spend longer in-store. There was no effect on other sales measures. These findings indicate that slow music alone will not raise overall turnover. To maximize its impact, retailers could integrate slow-tempo music into broader engagement strategies. Retailers could experiment with pairing slower playlists with tactics such as personalized promotions, interactive product displays, or loyalty incentives to extend their benefits beyond loyal customers to occasional shoppers. Moreover, shops that have a relatively higher share of loyalty members in their customer base could benefit more from having slower music, which might also be time-dependent.