Sennheiser SPORT True Wireless Instruction Manual page 13

Getting started
4. Installing the Smart Control app on your
smartphone
Smart Control
"Sennheiser Smart Control"
The Sennheiser Smart Control app allows you to use all functions
and settings of the earbuds, to set the "Adaptable Acoustics" feature
to match the ear adapters used (open or closed) and to e.g. adjust the
sound to your liking using the equalizer (> 20).
SPORT True Wireless | 13