Samsung P55 - Manual (Page 66)

6
Selecting Digital Output in the DVD Player Program
To use 5.1 channel speakers, you need to install the CyberLink Power DVD program from the CyberLink DVD Solution
Installation CD (or System software Media) provided with your computer, then change the settings as per the following.
The CyberLink PowerDVD program is optional and may not be provided depending on the model.
1
Run CyberLink Power DVD program and click the Configuration icon ( ).
2
On the Audio tab, set the Audio Output setting to Use SPDIF and click OK.
Now, you can enjoy home theater using DVD titles.
To control volume for your .1 channel speaker, use the control on the digital amp. (Please refer to the speaker manual.)