To accurately measure the impact of sound and music on sales in your retail environment, you should use reliable and valid methods of sound and music evaluation. For instance, customer feedback can be collected through surveys, interviews, focus groups, or online reviews. Additionally, customer behavior can be tracked with cameras, sensors, eye-tracking, or RFID tags. Furthermore, analyzing sales data and comparing it with the sound and music variables in your store can help measure sales performance. Moreover, employee feedback can be gathered through surveys, interviews, or meetings. Finally, employee behavior and performance in relation to the sound and music in your store can be measured with productivity, efficiency, quality, or customer service indicators.