Sennheiser HD 450SE Instruction Manual page 32

FAQ/If a problem occurs ...
32 | HD 450SE
1. Switch off the headphones (press and hold the on/off button for
2 seconds) and then start pairing mode (press and hold the on/off
button for 4 seconds) (> 17 and 14).
2. Simultaneously press and hold the on/off button and the 3-way
multi-function button for 3 seconds.
The LED flashes purple 3x. The Bluetooth pairing list is deleted.
The headphones then stay in Bluetooth pairing mode.
1
ON
OFF
Hold
Hold
4s
2s
2
Hold
ON
3s
"Pairing"