If you’re in the market for a new surround receiver you’ll no doubt find a bevy of new bells and whistles awaiting you, especially if it's been a few years since your last upgrade. Aside from things like HDMI switching, iPod docks, satellite radio integration and automatic calibration there are new speaker configurations and volume balancing technologies available.
Starting off with Dolby, as any discussion of surround sound should we have Dolby Pro Logic IIz, which builds on the venerable Pro Logic IIx by adding two “front height” channels. The additional front channels are intended to give a more realistic sense of height in the sound stage. For example rain would sound as if it was falling from high to low as opposed to just reverberating in a horizontal plane.
Moving on to THX’s Loudness Plus we get into the volume balancing part of the equation. Loudness Plus is designed to make reference level (0 db) a little more practical in real-world listening environments. Or to quote THX directly: “THX Loudness Plus automatically adjusts the front-to-back speaker level relationship as you turn the volume level down”. In that same vein Audyssey’s new “Dynamic Volume” and “Dynamic EQ” are designed to make sure subtle details aren’t missed at low volume levels.
That was super quick gloss-over version of these new features and formats and if you’re in the market for a new AVR definitely research each of these features in more detail as they offer the potential for significant sound improvement over previous generation AVR’s.