Have a read, I am upgrading from the strdb-925 on Tuesday to a Denon avr-1803 which does all the 6.1 sound formats.
DTS-ES Extended Surround
DTS-ES is a new multi-channel digital signal format developed by Digital Theater Systems, Inc. DTS-ES is upwardly compatible with the conventional DTS Digital Surround format, while significantly expanding 360-degree localization and spatial
expression utilizing surround signals that have been further extended. Commercial use of DTS-ES was introduced in theaters in 1999. DTS-ES includes the Surround Back (SB; also known as Surround Rear) channel in addition to the existing 5.1 surround channels of FL, FR, C, SL,SR, and LFE, enabling surround playback from a total of 6.1 channels. Due to differences in surround signal recording methods, DTS-ES offers two types of signal formats: DTS-ES Discrete 6.1 and DTS-ES Matrix 6.1.
DTS-ES Discrete 6.1
Discrete 6.1, the latest format, utilizes the digital discrete method to record all 6.1 channels, including the newly-added SB channel, as independent channels. A major feature of DTS-ES is its expressive power. Since the SL, SR, and SB channels are fully independent, sound can be freely designed and sound images can move freely and rapidly amongst each other within a background sound that envelopes the room from all sides.
DTS-ES Matrix 6.1
ES Matrix processing, developed by DTS, recreates the original 6.1 channel soundfield by extracting the Surround Back information from the encoded Surround Left and Surround Right channels, and is superior to generic "logic" decoding as the ES Matrix function utilizes the professional DTS-ES decoding algorithm as found in DTS-ES equipped movie theaters.
Dolby Pro Logic II
The Dolby's newly developed Pro Logic II decoder reproduces dynamic 5.1-channel surround sound from any 2-channel source: DVD, VHS and television broadcasts, radio, and CDs. Dolby Pro Logic II uses matrix decoding technology that has been
dramatically improved over Pro Logic. With Pro Logic II, for instance, the Surround (Rear) channels are in stereo (only mono with Pro Logic) and playback covers the full frequency range (only up to 7 kHz with Pro Logic). These improvements let you enjoy a wide variety of 2-channel sources with the exciting effects of 5.1- channel surround sound.
Dolby Digital EX is pretty much the same as DTS-ES Matrix 6.1
