Continuing with Denon's acclaimed attention to build quality and high standards of audio and video excellence, this new product brings you the most lifelike theater experience without the need for a degree in engineering. The ADV-M51 is equipped with Dolby Virtual Speaker, a revolutionary surround format developed by Dolby Laboratories. Dolby Virtual Speaker effectively allows listeners to enjoy the surround sound effects of multi-channel playback with just 2 front speakers connected to a DVD system equipped with power amps for the 2 front channels. Since listeners do not need to set up center or surround speakers or worry about correct placements, they also save space.Dolby Headphone allows listeners to achieve the same quality of acoustic characteristics through headphones as they can from the speakers. This means that listeners can enjoy the dynamic surround sound of their home theater in the middle of the night, for instance, when neighbors might otherwise be disturbed.Hammerhead Sharc (MELODY100), the DSP from Analog Devices, is used for the decoder to further boost digital signal processing capability and also providing the highest dynamic range. Faster processing speed results in more complete surround decoding.