1. When using the USB-C audio cable, you can adjust the volume either by the headphones’ roller or by the volume controls on the connected device.
2. When using the 3.5mm Aux-In audio cable, volume cannot be adjusted using the headphones’ roller and can only be controlled via the connected device’s volume buttons. This design is consistent with other brands of over-ear headphones and is not a malfunction. Please rest assured when using.