back surround loudspeaker, are of course big improvements over straight 5.1 processing, and they are crucial improvements if you are serious about enjoying the magic that surround sound can bring.
      Now, what about the Dolby Digital PLIIX mode in the AVR300? It brings the same crucial types of sonic improvement over EX or ES, that the EX or ES modes brought over straight 5.1. But it does so to a hugely greater degree. On a variety of program material (most of it not even EX encoded) we directly compared, via the AVR300, straight Dolby Digital 5.1, to Dolby Digital EX, and to the new Dolby Digital PLIIX (to keep the comparison within the Dolby family). The sonic improvements (especially spatially) of EX over straight 5.1 were large and very important. But the further sonic improvements of PLIIX over EX were huge, stupendous, name your adjective. Once you have heard the AVR300 playing a video soundtrack in Dolby Digital PLIIX mode, you can't go back to anything less. It brings a new, much higher level of reality to surround sound, that makes other modes pale in comparison. The AVR300 playing in its brand new Dolby Digital PLIIX mode is simply the greatest thing since that proverbial sliced bread, a breakthrough revelation in home theater surround sound.
      Our previous spatially favorite mode for playing video soundtracks was THX EX (which we slightly preferred over Dolby EX). And THX has made their house specialty the rich portrayal of ambient surround space. But, with the huge spatial improvements achieved by Dolby Digital PLIIX in the AVR300, far beyond what THX EX achieved, who needs THX? Clearly, Arcam was right and wise to dump THX from the AVR300. Dolby Digital PLIIX in the AVR300 is the new state of the art for surround sound from multichannel digital sources.
      What are the specific sonic improvements of Dolby Digital PLIIX over EX, as heard in the AVR300? First, consider the space portrayed in back of you. PLIIX gives it a cogent, coherent specificity and reality that goes far beyond EX. EX was an important advance over straight 5.1, since it at least portrayed some sense of the large recording venue's size behind you, thereby immersing you in that space rather than leaving you merely peeking in the doorway, as straight 5.1 did. But, as good as and as important as EX was, when something better comes along the human ear/brain is very quick to hear the deficiencies of the older system, especially in our direct comparison as afforded by the AVR300, which is so superbly revealing of spatial information that it highlights the sonic improvements of PLIIX, probably more than other forthcoming PLIIX units will, and thereby also discloses the sonic shortcomings of EX in comparison.
      With EX, the information you receive from your back merely tells you that there's some vaguely spacious, amorphous space in back of you. In contrast, Dolby Digital PLIIX in the AVR300 defines the boundaries and the acoustics of that portrayed space in back of you. For the first time, you can hear where the walls are of that space, how far away they are, and how the various sounds from the stage up front are reflecting off that back wall. This specific information, subconsciously decoded by the human ear/brain, makes the whole space in back of you sound far more real, and makes the sense of being truly immersed in that alternative space far more persuasive and believable.
      The whole point, and the whole magical experience, of surround sound is to persuade your subconscious to suspend disbelief. We tried one soundtrack after another, one scene and setting after another, and the sonic results were always the same. The sense of being transported to and immersed in the real acoustic of the alternative recorded venue is so persuasive from the AVR300 via Dolby Digital PLIIX, that every time we switched back to EX the whole surround space, and the whole surround experience, was like a mere caricature of the real thing as we experienced it via PLIIX (and straight Dolby 5.1 without the back surrounds sounded like a weak joke). The moral is simple. Unless you are experiencing multichannel videos via Dolby Digital PLIIX on the Arcam AVR300, you're just not cooking with gas. That's why you'll want to buy the AVR300, even if you only will use it as a Dolby Digital PLIIX processor for the rest of your system.
      The cogent reality of the portrayed space in back of you, via the AVR300 and Dolby Digital PLIIX, also makes flyovers much more convincing. Flyovers have always been a tricky illusion to portray, since back channel information has always been so weak and scarce (the front stage has three discrete channels devoted to portraying it with spatial accuracy, but the back channel has never been discrete, and has been only been a mono derivation by matrix). With prior decoding modes, including EX, even the best recorded flyovers started only vaguely in back, and in part seemed to start inside our head. But with PLIIX now portraying the back channels in stereo, the flyovers finally start at the rear with meaningfully specific spatial definition of where they are starting. The many flyovers and rollovers in the Star Wars videos finally make sonic sense, and the dual flyovers (one flying machine to either side of you) are especially realistic, thanks to their starts at your back finally being in stereo.
      The cogent reality that Dolby Digital PLIIX brings to the space in back of you also applies to the large venue space portrayed at your sides. In fact, with PLIIX the whole of the large acoustic space, of the recorded venue, is defined much more specifically all around you, and thus is much more convincing and believable all around you. The sense of being truly immersed in that large alternative space, and of that venue sounding persuasively real, is far superior with PLIIX on the AVR300 than with EX.
      Dolby Digital PLIIX is also a big advance over EX in portraying the stage up front. We hear a number of distinct sonic advantages that PLIIX brings to the frontal stage portrayal, when directly compared to EX. First, all direct sounds (including music, voices, and sound effects) have a more natural, realistic quality. They all sound less artificially forced, and more naturally open, airy, and relaxed. They are also more articulate and coherent, with less of the weird phasiness that EX and previous Dolby modes imposed on the front channels (due to their subtractive matrix). It's as if the stage information were being played through a higher fidelity amplifier. We suspect that the new matrix for Dolby Digital PLIIX actually also improves upon the sonic quality of the matrix derived front channels, compared to the matrices of previous Dolby modes, even while it dramatically improves the sonic quality of the information fed to the various surround channels, especially the new stereo and full range back surround channels.
      Second, with Dolby Digital PLIIX on the AVR300, the front stage is wider and deeper than it is with EX (which in turn is better than straight 5.1, with its shallow 2D stage). Stage ambience is richer, and the whole stage space up front is much better defined and more real, just as we found the surrounding side and back spaces to be.
      And now we get to the really good stuff, some really important sonic advantages that Dolby Digital PLIIX through the AVR300 brings to the stage space up front. We noted above how we have previously discussed an important advantage of back surround loudspeakers, as fed by an EX type matrix (even for soundtracks that are not EX encoded). The back surround channel feeds information to your ear/brain from your back side, and this psychoacoustically allows the images on the stage up front to pop, to become solid 3D entities, instead of merely being flat cardboard cutouts as they are when there is no back surround channel (as with straight 5.1 playback mode). Well, PLIIX through the AVR300 takes this same sonic advantage a giant leap further. For the first time, PLIIX also clearly portrays and defines the space itself behind the performer or stage sound, and the distance from that performer to the stage wall in back of him. This gives the performer a whole new measure of convincing, believable presence in that stage space, and in front of you in the large alternative venue space you both share. This effect sounds so real that it's almost spooky. The performers acquire such a believable presence in the same large space, which you also hear portrayed all around you with PLIIX, that aurally the performers seem to literally be there in the same hall with you, and you with them, in a way that transcends what previous modes like EX are able to achieve. When we switch back to EX the performers still have some 3D tactile body, but they seem plastered against the back wall of the stage, with no space defined behind them, instead of being out front on stage, and hence part of the same acoustic that we hear ourselves being in.
      Dolby Digital PLIIX has two effects here, working in complementary synergy. Firstly, the new realism of the stage space defined behind the performers puts the performers out into the large hall, which gives added realism to the whole illusion of you being immersed in that same hall with the performers (note that the reflections off the hall walls from the performers acting as sound sources, which now include the delays that clearly portray them as being some distance from the back stage wall, helps to define and make more real the boundaries and acoustic environment of the whole hall around you). Secondly, and in complementary synergy, PLIIX's new extra realism and believability for the whole hall space, including now a believable stage space in back of the performers, makes the performers themselves (and all sounds up front) much more three dimensional, solid, and believable, since aurally you can now sense that the performers are right there, sharing with you the same large hall space in which you hear yourself immersed. Indeed, with PLIIX through the AVR300, the newly portrayed space behind the performers sounds so real that you could swear you can hear the back side of each 3D, solid performer (and you literally can, since it is the back side radiation from each performer that reaches and bounces off the now well defined back wall of the stage). This new stage realism is a stunning advance over EX, in achieving the magic of total aural believability for our surround systems. Note again that we heard these sonic benefits, and huge advantages of PLIIX over EX, even on soundtracks that are not EX encoded, which means that PLIIX is a terrific enhancement tool for your whole video library.
      The fourth stage advantage we heard in Dolby Digital PLIIX over EX is more subtle, but is nevertheless very important. The three sonic advantages above combine together, to yield an unexpected further benefit. The second sonic advantage above of PLIIX was that the sound quality is less artificially forced, and more naturally relaxed, open, and airy. The first sonic advantage above was that the stage space is wider, deeper, and richer in ambience. And the third sonic advantage above was that all sounds on stage now each have a rich and well defined space around each of them. Now, combine all three sonic advantages together, and apply them to the center channel dialogue.
      What does this accomplish? First, some preliminary background. As you know, there's an unfortunate habit (left over from soundtrack mixing needs for commercial theater playback) of putting all dialogue in only the center front channel, and not spreading it to all front channels. This leads to the sonic anomaly that, even when characters are visually spread across the screen (perhaps even speaking from opposite sides of a wide screen), their vocal dialogue emanates only from the center channel location, so that all the characters sound as if they are trapped within the small box of your center channel loudspeaker, instead of being part of the huge, open surround space that your system is portraying for all other soundtrack content. Furthermore, voices for dialogue are typically very closely miked for purposes of clarity, which makes them sound as if they are speaking in a very small, confined space, and this creates the sonic anomaly that, even when characters are visually located in the large acoustic environment portrayed on screen, they sound as if they are confined in a small booth (even smaller than your listening room), and their voices have a canned, dry quality. The end result of these sonic anomalies is that the dialogue, and the characters on screen speaking that dialogue, do not sound as if they are part of and located in that same large acoustic venue that is visually portrayed on screen, and that you hear all around you for the rest of the soundtrack content (music and sound effects). When the dialogue does not sound as if it is in the same large space, then some of the illusion is destroyed, and some of the magic is lost, the magic of spatial immersion and suspension of disbelief that you have worked so hard to achieve in your surround system.
      Well, Dolby Digital PLIIX through the AVR300 manages to bring back some of this lost magic, by making the center channel dialogue sound more consistent with the large acoustic space portrayed by all the other soundtrack information. By making the dialogue sound less artificially forced and more relaxed (and diffuse) than other processing modes, PLIIX ameliorates that canned, confined, closed in quality that the typical too-close miking imposes upon dialogue. By widening and deepening all information related to the stage space, PLIIX liberates the dialogue from being confined inside your small center loudspeaker box, and helps to integrate it better with all the other, richly spatial information up front. By portraying deeper and better defined space behind each performer, PLIIX further spatially liberates the dialogue, projecting it out into the large acoustic venue portrayed by your system, and giving you a much better sense that the characters are 3D entities with 3D locations out in the large acoustic venue they share with you, rather than merely being plastered flat against the back wall or trapped inside a small loudspeaker box. In short, with PLIIX through the AVR300 the characters sound more like flesh and blood reality, and they are more part of the whole scene and whole action, whereas with EX they are flatter, more confined, and more phantomlike (and with straight 5.1 they are a Lilliputian joke).
      As we've said before, the characters are the central point of most movies, and, if you can't aurally believe in the characters, then you can't really believe in the movie as a whole, and you have not truly suspended disbelief and been aurally transported into the movie. Thanks to the Arcam AVR300 and its new Dolby Digital PLIIX, you can truly believe, as never before. When we compared EX to PLIIX on the AVR300, on scene after scene, soundtrack after soundtrack, our reaction was always the same. We already knew what to expect, but we were still stunned afresh every time, with every new comparison. When we switched from EX to PLIIX on the AVR300, the improvement in sheer reality, for the characters as well as the whole surround environment, was so huge that it stunned us afresh each and every time.
      All these dramatic sonic benefits from the new Dolby Digital PLIIX crucially depend on the host processor (and power amplifier) being superbly transparent, pure, and spatially revealing. If you were to buy PLIIX implemented in a host processor that was less than superb in these crucial aspects, then PLIIX could not fully achieve the spatial magic we heard above through the AVR300, and all the above described sonic benefits, since some of the subtle spatial information needed to create the PLIIX magic would be obscured, distorted, or lost by a less than superb host processor.
      That's why Dolby Digital PLIIX and the Arcam AVR300 are a marriage made in heaven. Both are sonic breakthroughs, achieving new levels of spatial reality not heard before. The Arcam AVR300 is superb in the sonic strengths needed here: transparency and clean purity, and, perhaps most importantly, the vivid portrayal of space itself, a particular Arcam skill already noted in our review of Arcam's AV8 processor. The AVR300 allows the breakthrough spatial sonics of the new PLIIX mode to sound their glorious best, and may well sonically surpass other host processors that introduce PLIIX in the near future. Thus, the Arcam AVR300 is not only the first processor/receiver equipped with Dolby Digital PLIIX, but is also the first with the most.
      The only thing that will probably surpass today's Dolby Digital PLIIX through the AVR300 is in the future, when blue laser discs make possible 7 channels (or more) that are truly discrete, which is still several years away. Dolby and DTS have already announced new processing modes for multiple discrete channels from future blue laser DVDs, and we expect that Arcam will again be first with the most for handling these future discrete soundtracks. Even then, in the future, when you'll still want to play soundtracks from legacy red laser DVDs, Dolby Digital PLIIX as implemented now in the AVR300 will probably continue to be the option that brings you the most magic.
      Incidentally, Dolby Digital PLIIX could theoretically also be applied to enhance 5.1 surround material from high resolution audio discs (DVD-A and SACD), by adding stereo back surround channels, and indeed the Dolby technical literature discusses this possibility. But to put this into practice would require special and expensive hardware, because of the record industry's paranoia which dictates that this material be in either analog or encrypted digital form when transmitted from the disc player, which means that the surround processor would have to either add hardware to decode encrypted digital input, or would have to include 6 channels of A/D conversion. That's beyond the budget of even expensive high end surround processors, and certainly beyond a moderately priced complete receiver like the AVR300 (which does of course include 2 channels of A/D conversion, so it can perform surround enhancement for 2 channel analog program sources).
      With its superb transparency and portrayal of space, the Arcam AVR300 is a unique space machine. Using the AVR300 in the new Dolby Digital PLIIX mode (with 7 loudspeakers), for playing all your video soundtracks, is like taking a joyride in a space machine. Likewise, using the AVR300 in Neo 6 Music mode (or PLIIX Music mode), for playing all your two channel music library, is like getting a ticket to the original hall.

Loudspeaker Placement

      Since the AVR300 works such stunning spatial magic with Dolby Digital PLIIX and 7 loudspeakers, we of course recommend that you employ 7 loudspeakers. Ideally, the back surround loudspeakers should be high quality and full range (or nearly full range, say down to 40 Hz), since PLIIX sends a full range signal to the back surround channels, and since our previous research has demonstrated that it is sonically important to radiate the entire spectrum, from at least the upper bass, at the back side of a listener, in order for him to perceive true immersion in the large space of the alternative venue.
      Of course, the two back surround loudspeakers should also be spread apart from each other, since with PLIIX they are now reproducing stereo information, instead of mono information as with EX and ES. But this creates a potential quandary. Where, now, do you put the side/rear surround loudspeakers? For playing multichannel surround from high resolution audio discs (DVD-A and SACD), which put out only 5.1 channels, and which cannot be enhanced to 7.1 channels since they must pass straight through the AVR300 in analog direct mode, it would seem that you'd want the side/rear surround loudspeakers placed at or near the classic 45 degrees off the back central axis. But this location for the side/rear surrounds is much too close to the spread out locations of the two back surrounds (which should be at least 20 degrees and possibly 30 degrees off the back central axis),

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