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Home Theater Cruise Panel 2: Setting a New Surround Sound Standard

by , November 08, 2005

We spent about 2.5 hours in an unexpectedly grueling session with renowned recording engineers Chuck Ainlay, Ed Cherney, Frank Filipetti, George Massenburg, Elliot Scheiner, and Al Schmitt (as well as host Gary Reber from Widescreen Review magazine.) We were truly honored to engage in a panel discussion with such legendary recording engineers, but ended up being a bit disappointed with the way the event was chaired.

We initially believed the discussion was going to deal primarily with multi-channel surround recommendations for the new surround formats (TrueHD and DTS-HD) and how they relate to music. Instead, we heard a lot of bashing from no other than Gary Reber about how " THX is all wrong for the home theater environment" , " manufacturers don't know what they are doing ", and how important it is to have 5 identical direct radiating speakers placed equidistant from the primary listening position. It was obvious from about five minutes into the discussion that Gary had an agenda. It was to slam manufacturers and THX for promoting all of these new formats and speaker options, while promoting his own misguided views on how the human ear perceives sound. In fact, he postulated how he allegedly hears differently than professional sound engineers. Indeed, his expressed views differed from all of the peer reviewed research done on the human ear and sound perception. He initially spoke in the authoritative tone of one who was speaking for the panel of recording engineers. Fortunately, most of them made the disclaimer that they didn't share his viewpoints.

Unfortunately, he kept reiterating his same misguided views and exercised his free reign to hijack the discussion and thwart any real progress for developing agreeable and practical standards for the industry. A few quotes from Gary included: "THX recommendations promote no imaging and only diffused sound with no consideration for time alignment" and " dipole speakers are all wrong". What Gary failed to realize was the well documented and undisputable research on human hearing and how we perceive and localize sound.

For more information on this topic, please review our articles on Human Hearing

ITU 5.1 Discussion

Gary, as well as one of the more vocal panelists, Frank Filipetti, promoted their strong opinions against ITU 5.1 ( see diagram to right courtesty of Best Buy ) and even went so far as to call it a bogus standard. Frank Filipetti also stated that "all ITU research was done using classical music, where surround speakers were used primarily for effects and ambience, and rear channels were not considered equal partners in the presentation".

Well, we can agree that there is a need for the use of direct radiating speakers with respect to high resolution audio formats vs. film. The trouble is, most of the panel's engineers seemed unconcerned about exactly how the speakers were placed. In fact NOT ONE of the panelists moved the loudspeakers from their default positions in the listening room (though it was not arranged in the ITU 5.1 standard). Keep in mind, we are not necessarily endorsing the ITU 5.1 standard, but looking at the majority of opinions from the panel and what we've heard ourselves, it makes more sense than needless bashing of the industry or putting forth new proposals when the current ITU works pretty well. It also works much better for hybrid rooms that will get some use for home theater movie soundtrack playback. All things considered, however, we feel the same as the panelists - a little adjustment will not damage the surround experience - at least not for music playback.

Defining Full Range Loudspeakers

Gary Reber again threw a wrench into the discussion by trying to determine what is meant by "full range". Was it down to 20Hz or 40Hz? He seemed more concerned with putting a number to their definition rather than realizing that most so-called full range speakers cannot play down to 40Hz, let alone 20Hz, linearly without major compression at high output levels. As we have repeatedly shown, focusing on the numbers alone merely misses the real important metrics in favor of ones that are easily met and documented. There was some discussion of the LFE channel and what it means to the surround sound mix engineers. A general consensus among panelists was that the LFE channel was not very important, and some engineers seemed to confuse it with the subwoofer output of a bass managed system rather than a dedicated track for sweetening or effects. Our position is that systems which utilize subwoofers have a tremendous advantage in smaller home theater rooms, enabling the user to better tackle standing wave issues and smooth out the low frequency response. There is nothing wrong, however, with engineers choosing to mix in 5.0.

Gary Reber drove the discussion - sometimes forward, and often in circles or backwards, but his main contention seemed to be that the billion dollar film industry should conform to the as-yet-undetermined whims of the multi-channel music industry. He continued to drill his agenda on defining what angles the speakers should be placed. He insisted that humans could hear equally good imaging and localization in all directions, disregarding the mountains of research from some of the world's most renowned acousticians. He continued pushing his recommendation of sharp toe in for the front speaker pairs from the listening position and some obscure angles for the rear channels (actually we were unsure of the specific angles as they seemed to change and were not legible on the white board). Many of the panelists, such as Chuck Ainlay, disagreed and said the speaker placement should be more general and flexible and should only define a window for recommended placement, NOT a biblical absolute. They, as well as ourselves, attempted to correct Gary 's misguided viewpoints about how the human ear perceives sound but he again insisted his listening experiences are much different than what documented research shows.

It was around this time that we noticed many people actually starting to leave the room and exit the pointless debate and obvious agenda-driven discussion.

We suddenly started getting déjà vu, as if we were listening in on a seminar for exotic cables. We wished Gary had attended the panel session on video with ISF that drilled in the mantra about CIE theory: "if you can't measure it, you can't manage it ". In any event, despite the disagreement with his statements from many panel members, members of the audience, and the fact that people started bailing out of the room after he continued pushing his viewpoints ad infinitum, he still insisted on reiterating it two or three times more during the session and again afterwards during an informal discussion.

The main problem with following the suggestions that Gary presented (this was less a panel discussion and more a "Widescreen Review positional stance on 5.1 audio") is that setting a system up as such can at best only guarantee one sweet spot at a primary listening position. We don't believe in designing a home theater or music playback system for one money seat. Ideally, we agree with the THX mantra that every seat should be a good seat . Firing full range speakers at sharp angles equidistant from one listener will most certainly not guarantee this realization which seems more appropriate for a nearfield studio listening environment, NOT a home theater / music playback system.

Some refreshing news about this forum session was that many of the panelists agreed on the following points:

  • Converging to one platform for all formats is a good goal
  • 5.1 should be the mainstay format for music mixing to avoid industry confusion
  • The solution needs to be as simple as plug and play

What really shocked us, though, was the lack of awareness and misconceptions that many of the panel members conveyed towards home theater and consumer audio. Frank Filipetti even went so far as to complain about the alleged issue of doubled-up bass management from the DVD player and receiver which made it clear to use he probably didn't have a whole lot of experience interfacing the two devices. If he had, he would have known it's an almost impossible scenario to occur. If an analogue connection is made between the receiver and DVD player, then bass management will be used in either the DVD player (typical) or the receiver, but not both. If a digital connection is made, such as IEEE 1394, D.Link, or HDMI, then the bass management will be handled in the receiver and not the DVD player.

THX & Electronics Manufacturers - Those Evildoers?

Despite Gary and Widescreen Review's grim views on THX and electronics manufacturers for allegedly creating the confusion by adding more formats and speakers to the multi-channel mix, we conversely feel both THX and electronics manufacturers should be applauded - and in a big way.

First, we recognize THX for their attempt to create basic standards in the industry in efforts to reproduce consistent sound in the home theater environment as closely as possible to the original dubbing stages. Secondly, we congratulate electronics manufacturers for providing the necessary hardware in achieving this, as well as implementing enough flexibility in their designs to satisfy nearly every conceivable user application. Think about this, for example: Right now, you can connect a universal DVD player to a receiver via IEEE 1394, D.Link or HDMI and put in a CD, DVD-Video, DVD-Audio, SACD, DVD-R/RW, CD-R/RW, HDCD, MP3 or WMA disc and the receiver will automatically adjust the output and bass management for you, routing the correct audio channels to the correct loudspeakers automatically . Now, that is very impressive indeed and is not something to toss aside or scorn. Confusing? Yes - to the manufacturer, but greatly simplified for the user. It is interesting to note that the demos played on the cruise did exactly that, using a Yamaha universal DVD player and receiver. One cable sent all of the sound to the receiver digitally from the DVD player with all formats fully supported with the exception of some special pre production demo discs in PCM that utilized the 6 channel analog connection route.

Our Recommendations

We start with one of the several well thought out THX speaker placement guidelines (note we agree these are simple guidelines and not a biblical source). The goal is great localization for the front soundstage, tight articulate bass in all seats, and a surround array for movies and music with some sense of directionality for games. The surround array should envelope more than localize though with some of our recommended addendums to the THX configuration you can have the best of both worlds with a simple automated configuration change, and/or some trick post processing modes incorporated in many of today's receivers.

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In this recommendation, you can use identical performing LCR speakers, with Dipole/Bipole or Direct radiators for the Surround channels and Direct radiators for the Surround Back channels with the listener located about 2/3 into the room from the front speakers and digital delay compensation implemented on all speakers to properly time align the speakers.

In our discussions with THX in the past, it was quite clear that they had a very open view about how to choose surround speakers which they claimed depends on two variables:

  • The room
  • The type of listening

Their recommendations are based on the desire to accomplish two conflicting and legitimate goals with a single speaker configuration - non distracting envelopment of the entire audience versus having localizable sounds in the surround field for exciting and immersive game play. Depending on the rooms size, and available speaker placements the installer/consumer can choose between dipole, bipole or monopole. To decide it's usually best to start out by listening to pink noise through various speakers at various distances and select the ones that best suit the intended application.

Read our FAQ interview for more information on THX Speaker Placement Guidelines .


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Axiom Audio Quadpolar QS8

RBH Sound 66-SE Bipolar/Dipolar

We would like to expand on this recommendation slightly for a more centric focus on music without compromising home theater by suggesting using a hybrid Dipole/Bipole speaker located 1-2 feet behind the primary listening position and located 2-3 feet above ear level. A hybrid dipolar/bipolar speaker system such as the RBH Sound Signature 66-SEs function such that the woofers operate in phase and the tweeters operate out of phase - combining the best of both worlds between direct radiators and traditional dipolar speakers. This type of speaker topology takes advantage of the spacious sound of a dipole speaker while maintaining the timbre matching of the rest of the system. There are other trick solutions offered by manufacturers such as Axiom Audio's Quadpolar designed QS4's and QS8s.

Using direct radiators, the surround back channels can then be placed 6-8 feet apart at the same height as the surround speakers. The consumer can now use this system in a full-fledged 7.1 configuration for music and movies by simply engaging in a post processing mode such as PLIIx Cinema mode for movies and PLIIx Music mode for multi-channel music. If the consumer prefers a more direct sound behind them, they can simply switch off the side channels and redirect the surround info to the back channels.

Receivers from Denon, for example, can automatically do this per signal type and input and only require a one time simple setup which can be done by the consumer or professional installer. Other options we discussed include using speaker systems from companies such as Harman or B & W's DS8S (pictured right) that allow the surround speakers to switch between dipole and direct radiators via a 12V trigger. Again, manufacturers such as Denon incorporate this feature on many of their upper end receivers for this very purpose.

A Note on Dipole Speakers and Movie Soundtrack Reproduction

One unsettling discussion we had with Gary Reber included a conversation about how he preferred a 5-way full-range loudspeaker system for movie soundtracks not just multi-channel music. His basis for this consisted of several points:

  • Dipoles were originally developed during the Dolby Pro Logic era when surround channels were mono and the dipole was designed to recreate the effect of an array of loudspeakers on the dubbing stage.
  • Several "DVD remixers" are using the nearfield multi-channel mixing scenario (5 full-range loudspeakers) for remixing the stems from motion picture films into DVD movie soundtracks for the home.

While we respect Gary 's right to his opinions, we have a few problems with this approach. First of all, the right way to reproduce a film soundtrack is to best emulate the sound at the dubbing stage (where they mix the film) in the home theater environment. This is, by definition, right because it means that what the original Mixers intended is preserved to the best degree possible. On the dubbing stage, there are arrays of loudspeakers utilized for Surround Left, Surround Right and Surround Back channels. There is no such thing as a "point source" or uni-directional surround sound source in the dubbing stage environment as that would be distracting. The goal of film mixing is to create a surround environment, not to provide distracting surround elements that draw attention away from the screen. In the home theater, the loudspeaker that best allows the emulation of an array of loudspeakers is the Dipole. In home theater, you aim the null of the Dipole speaker at the listening position and thus create a diffuse sound field that more closely emulates the sound heard on a dubbing stage. Combine this with good room acoustics and you can really have an effective room that recreates the soundtrack intended by the Mixers and the Director.

Since film mixers do not want point-source audio coming from the surround channels in mixing environments for film, there is no situation whereby utilizing five, six or seven full-range loudspeakers would have an advantage. This is not a matter of opinion; it is the very definition of what is considered the right way of remixing DVDs - namely emulating the sound of the original source. This is the same argument we use for esoteric cables. The right sound is one derived from an unchanged signal. While some people may feel that esoteric cables may make the sound "better" what they are truly expressing is their desire to hear a changed sound from the original. The unfortunate truth, however, is that there are several re-mixers who are taking stems from dubbing stages and utilizing near-field recording studio-style audio rooms to generate DVD-specific soundtracks. We believe this practice should stop.

Wrap Up

Overall, the Home Theater Cruise panel discussions were certainly lively. It would be good for the staff to perhaps select less agenda-driven moderators in the future, though we have doubts that this will ever happen. When you have experts on a panel it is good to hear what they have to say without necessarily force-feeding the discussion to match a pre-arranged script. We appreciated the feedback, perspectives and insights offered by the panelists and look forward to continuing to work with NARAS P & E wing 5.1 group, the organization chaired by George Massenberg, to address the needs and issues associated with the music recording industry.

 

About the author:

Gene manages this organization, establishes relations with manufacturers and keeps Audioholics a well oiled machine. His goal is to educate about home theater and develop more standards in the industry to eliminate consumer confusion clouded by industry snake oil.

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