Sennheiser HD 450BT Noise-Canceling Wireless Over-Ear Headphones (White) - Manual (Page 19)

Using the headphones
HD 450BT | 19
Adjusting the volume
You can adjust the volume for music, voice prompts, beep sounds,
and phone calls.
▷
If you are playing music or are on a call: Press the rear part or the
front part of the volume button to increase or reduce the volume
for music and phone calls.
When the maximum or minimum volume is reached, you hear a beep.
WARNING
Danger of hearing damage due to high volume levels!
Listening at high volume levels can lead to permanent
hearing defects. Toggling between the audio sources
may cause enormous volume jumps that can perma-
nently damage your hearing.
▷
Before putting the headphones on and before tog-
gling between audio sources, adjust the volume to a
low level.
▷
Do not continuously expose yourself to high volume
levels.
You can also adjust the volume using the connected Bluetooth
device.