I had no idea that adding two extra speakers into the mix would cause a convoluted confusion of operation modes of configurability. With no real help from Denon's operators manual, I configured these modes as I perceived logical and later confirmed my findings and/or suspicions with Denon's very knowledgeable tech support group. Tabulated below are the various configuration options for 7.1 audio playback, along with their associated explanations.

I personally preferred either "non matrixed" DD/DTS or no back channels when playing back concert DVD's or 5.1 music formats. In most cases, "matrixed" modes of DD/DTS did enhance my listening experience during movie watching, but I ultimately preferred these modes with a truly encoded DD 5.1 EX or DTS 6.1 ES source disc. I never really understood why there was a separate "EX" and "Matrixed" setting however, since both basically do the same thing whether decoding ordinary 5.1 or EX source material.

Aside from the "Seal of Approval' for good housekeeping, THX Ultra 2 sure does pack a lot of technology into a home theater product. Many of the tools are both useful and practical, though they can yield different responses depending on room acoustics, equipment, and personal listening tastes.

For example, I was pleased that the "Boundary Gain Compensation" feature was incorporated into the THX arsenal toolbox, which could provide most useful for systems like mine where the subwoofer is placed closely to a corner wall. What it essentially does is employ a HPF at around 55Hz to reduce subwoofer output below those frequencies in attempts to counter the added room gain of such position. While this can help, I would have preferred the incorporation of a parametric EQ with adjustable Q settings for group delay compensation to help better smooth out room response. I found that the "Boundary Gain" setting did indeed help flatten out the response of my subwoofer, but at the expense of adding phasing anomalies when sweeping from 100Hz down to 20Hz in my room with the main speakers set "large". I just couldn't get my subwoofer and main speakers to blend as optimally when the mode was engaged. Of course different rooms/speakers will surely yield different results. I recommend trying this feature in your system if your sub is located near a corner wall to determine what it can do for you.

This has the potential of being a very useful tool for those with less than bone crushing subs as it helps you set a point where the subwoofer distorts to limit its dynamics beyond that to avoid excessive clipping or distortion. I personally found little use for this feature with my reference sub and listening preferences

Part of the new THX Ultra2 specifications, include the provisioning of deriving 7.1 channels out of 5.1 discrete DD/DTS audio sources. I did discover positive sonic results for the Cinema mode, dependent on source material, in that I perceived a broader soundfield and less transitional panning between channels. However, I never came across an instance where I preferred the THX music mode over ordinary 5.1 DD/DTS. I personally felt that since my rear channel speakers imaged so well, adding the extra two back channels, especially in a matrixed fashion, only deteriorated their sonic attributes when playing back multi channel 5.1 encoded source material. As a caveat, I felt it fair to mention that my personal speaker placement set-up (mostly a result of room limitations) and speaker topologies do not fully comply with THX recommendations, thus users with THX recommended set-ups and speaker types may experience different results. I personally prefer the sound of direct radiating speakers over Dipoles for surround channels, particularly when listening to 5.1 music. I suppose the old Bugs Bunny saying " One mans meat is another mans poison. " may be applied most eloquently here.

Spending the past three months with the Denon AVR-5803 proved to be an eye opening experience for me. I learned to overcome the typical stereotype inbred into us audiophiles that receivers cannot be the epitome of high-end audio. I learned that a truly exceptionally engineered receiver such as the AVR-5803 can, in fact, surpass the performance and flexibility of many more costly separates and nearly all currently shipping separates and receivers in this price class. In my opinion the already two year old Denon flagship receiver still sets a benchmark to which receivers and separates solutions must be judged. Some may argue that $4300 is an awful lot of money to invest in a receiver, and that may be true. However, considering that no single receiver or separates solution at this asking price (and even a few thousand dollars more) offers this level of refinement, performance, and set-up flexibility, the AVR-5803 comes as an uncommon bargain. In fact, as a further personal endorsement to my satisfaction with this receiver, I am strongly considering the option of upgrading my reference system to incorporate the AVR-5803, where it may serve as the premier preamp/processor to replace my dated Aragon Soundstage, and the power amp for the surround channels. I don't believe I am ready to part with my old Aragon 8008 series amp for the front channels since it is such a killer amp, and I never know if I plan on testing some very inefficient difficult speaker loads in the future. However, one never knows what the future of audio will hold, and who may be releasing the next generation of gear that may knock the shelves off my entertainment center. I can assure you, however, based on their past product portfolio, and their very talented engineering staff and tech support people, that Denon will be one of those manufacturers.