Are deeply curved LED screens the way to the future for cinema?

[Frank Angel]

There really isn't any reason why Left and Right screen channels can't be placed on either side of the screen; in live concert venues, lines-array clusters -- sometimes massive -- are the systems of choice for concert sound for the biggest artists. Using that configuration in a cinema with a direct view LED screen, i.e. placing the speakers a few feet to the right and left of the screen shouldn't be problematic in a whell designed and properly tuned system. It's the center channel that still would be an issue, but I actually have head a setup that worked fairly well, where the channel, much like the Mayer concept is reflected back to the audience, but with a twist. This theatre was designed with an acoustic "shell" over the orchestra pit which extended in front of the proscenium arch (and the screen). These acoustic panels were part of the angled ceiling of acoustic reflective material that is commonly used for spaces where orchestras perform. For movies, the pit is lowered and speakers bins for the center stage channel were lowered into the pit on their sides and aimed at the angled/slopped ceiling which reflected and directed center channel sound at the correct angle to the audience. It probably would be easier for an acoustic designer to manipulate such a reflected surface above the screen a lot more accurately than using the hard screen that is fixed and probably not an easily maneuverable surface. Probably with good audio engineering, such a configuration could work. Certainly the Left and Right channels would be no problem -- I guarantee when Celine Dion performs, those line array speakers on either side of the stage make her vocals convincingly sound like they are coming from exactly her physical location on the stage. And one would think that with object-based mixes like Atmos, putting speakers to the left and right of the screen should be a walk in the park for the processor to place that screen sound anywhere it needs to be. I would posit that even with center channel speakers placed above or below the screen (forget about reflecting off it or anything else), Atmos should be able to cause the audience to perceive sound to come from behind that screen, left center or right.

My problem with big speaker arrays on either side of the screen, is they tend to just hang them and walk away, leaving them to be seen by the audience. Fact is, that placing speakers in an obvious visible location tends to make the listener locate the sound source visually and that can cause the brain to insist THAT is where the sound is coming from, NOT where the audio mixer intended it to come from, but hard locked to that visual cue...and of course the brain is correct, thus interfering with the illusion of what the sound mix is trying to create, i.e., that the sound is coming from the image...from the characters who are speaking. BUT, in a theatre that is well designed and specifically for this emitting screen system, speakers could easily be disguised on either side of it. Disney techs knew this, and when they opened THE LION KING at Radio City Music Hall, they brought in their own sound system, and, yes, even though they could have put Left and Right channel speakers behind the screen, they went with hanging line-arrays and subs on either side of the stage...and they covered them top to bottom with some sort of acoustically transparent material. While it didn't make them invisible, I am sure many in the audience weren't nearly as much aware of them as if they had left them uncovered.

There is a theatre on the St. Mary's Campus in South Bend IN that has surround speaker completely hidden in large circular designs on the side walls. It is amazing how simply hiding them gives the illusion that the surround sound is fully engulfing you. Once I experienced that simple means of enhancing the immersion illusion, I never could understand why after over half a century of the industry's obsession with "surround sound," side and rear wall speakers still sit exposed in the auditorium. How many times do I see audience members turning around looking at the wall speakers with a sound effect is prominent in the surround channel. Imaging how much more effective if there were no visual cue at all as to where that sound was coming from other than, you know...all around! Isn't that the whole point of what Altos is trying to accomplish? Yet there they still hang -- those give it away wall speakers.

[Steve Guttag]

Frank, the issue with that is that is messes up the stereo imaging. The sound should come from the image, not from the area beyond the image. The needs of a cinema are completely different than for a concert. In a cinema, you want point-source speakers for sound localization. With that, moving the speakers out of the screen area, moves the sound's location with it.

Compromises are made in large rooms where one sacrifices ideal localization for better coverage. Line arrays shouldn't be were one starts in a cinema but in a large venue with multiple balconies, they may be where one ends up.

[Steve Guttag]

The "Atmos Enabled" speakers (Klipsch has a line of them) sort of work, if well placed. BUT, a surround effect is much, much, much different than bouncing inherently direction sound cues, including dialog off of an LED screen. No matter what anyone tells you, unless you have a Trinnov Altitude, you are getting a VERY poor facsimile of cinema Atmos. It is like getting a VHS resolution video and comparing it to UHD.

[Bobby Henderson]

Very often in concert setups there are two or more vertical columns of speakers mounted above the stage on the lighting rig or other overhead hardware. That's in addition to any speakers off to the left and right ends of the stage. The vertical columns are stacked in a kind of arc, with the bottom enclosures angled down at the floor seats and the top speakers pointed more upward toward the cheaper seats.

[Marcel Birgelen]

Very often in concert setups there are two or more vertical columns of speakers mounted above the stage on the lighting rig or other overhead hardware. That's in addition to any speakers off to the left and right ends of the stage. The vertical columns are stacked in a kind of arc, with the bottom enclosures angled down at the floor seats and the top speakers pointed more upward toward the cheaper seats.

Those banana-shaped speaker arrays are so-called line arrays and in general they are a huge improvement compared to old-school PA systems with a bunch of stacked speakers. Like you already noticed, those speakers are pointed at specific locations in the crowd, the so called zones. Line arrays have the advantage of a much more consistent power level across the field and also severely limit noise polution if used correctly.

Line arrays aren't very commonly used in cinema, but Meyer Sound does actively use them in their cinema setups. I'm not against the usage of line arrays for cinema and I'm convinced it can solve quite some problems in big and complex rooms, especially those with balconies. But they aren't a magic solution to non-transmissive screens, as even Meyer Sound places them behind the screen, for obvious reasons.

Maybe a custom line array with both horizontally and vertically stacked units placed above the screen could each replace a traditional behind-the-screen stage speaker, but it will be hard to hide the fact that the sound originates from above the screen...

It's been about 25 years or so, but AMC used to have those torus screens that were kept in shape using suction... they had their sound system mounted above the screen. I've only ever seen one show in such a theater and I remember the screen to be pretty terrible, since it was all out of shape as that suction part apparently wasn't really working, but I don't really remember how good or bad the sound was.

[Allan Young]

Line arrays aren't very commonly used in cinema, but Meyer Sound does actively use them in their cinema setups. I'm not against the usage of line arrays for cinema and I'm convinced it can solve quite some problems in big and complex rooms, especially those with balconies. But they aren't a magic solution to non-transmissive screens, as even Meyer Sound places them behind the screen, for obvious reasons.

Didn't know they were called "line arrays" but you're spot on about them solving problems in large theaters with balconies. The Odeon Leicester Square's Atmos setup has a couple either side of the screen (and they didn't bother making any attempt to hide them)...

Odeon.jpg

[Frank Angel]

The sound should come from the image, not from the area beyond the image. The needs of a cinema are completely different than for a concert. In a cinema, you want point-source speakers for sound localization. With that, moving the speakers out of the screen area, moves the sound's location with it.

I am not sure if that is true, Steve. First off, music mixed in Left and Right channels is spread between them in a whole arc of the soundstage. Placing the point-source speaker beyond the screen by a few feet simply widens that soundstage and with music that is fine. Dialog is the issue; on the occasion that dialog is mixed to actually follow the characters in the image, there is no reason why localization of that dialog can't still be maintained by left and right channels. Even with the speakers behind the screen, localization of dialog and sound effects is always and illusion created by the sound mixer and where he/she pans that sound in the ratio of level between the left and right channels. The result is always a phantom location. That will still work if the speakers are behind the screen at either end or 3 feet to the left and right of it. It is not like in the glory days of 70mm with 5 channels behind the screen and then yes, spanning a character's dialog could almost be done matching the actually location on the screen with one of the speakers behind it. But even then, it was a phantom location created by the mix and not by the location of the physical speaker.

I would posit that moving the speakers a few feet beyond the screen perimeter, will in no way reduce the ability to place phantom sounds anywhere from dead center of the screen to anywhere in between in the stereo soundstage...same as is done when the speakers are behind the screen's left and right edge. Moving them further out, literally by a few feet, is not going to inhibit that ability. Sound localization was never a function of physically placing the speakers to match the location of the visual in the image, but always a function of the mix, placing phantom points of sound based on where the sound was placed in the mix between the two channels. In fact, with any well mixed soundtrack, using well-known phasing tricks, sounds can be made so seem like they are coming from wider than the physical screen. I don't think there would be any discernible impact on localization if the speakers for the Left and Right channels were place right at the screen's edge behind suitable, acoustically transparent mask material.

The much bigger challenge with a solid screen is what to do with that damn center channel speaker system!

[Steve Guttag]

Frank, you are just wrong on this one. I've heard MANY rooms with speakers behind and outside of the screen and even Flat movies where the left and right speakers are placed outside of that image on the "Scope" screen. When the sound is coming from beyond the image, it is very audible and triggers a sense of the sound and image are somehow not together. On the Flat movies you do get aways with music out there more but you get what I call "big sound" where the sound is larger than the image. You get a similar effect to sound coming from above the screen (there you also get a bit of a sync issue...even if things are perfectly timed). There comes a point where one's brain just doesn't buy the illusion. Heck, center speaker is even MORE fussy. You can be a foot off of center and one can pick that up easily (witnessed that one numerous times too).

As the screen gets wider/larger, the shortcomings of 3-screen channels become even more apparent as one cannot phantom channels 20+ feet away...it just doesn't work unless you are very far from the image...where channel localization is compromised due to room acoustics, as much as anything else.

One of the things that Dolby Atmos has introduced (and I've been a proponent for for decades) are the Left and Right "Wide" channels (I called them Left and Right "Outside" channels, back in the day). There is a difference between action on screen and sound from off-screen...be it an effect or spoken voice. The advantage of LW and RW is that you can now, legitimately, pull the sound to beyond the image with a coordination with the image. You don't get that with speakers just place outside of the image. The perception is dramatically different when you cross that line.

As to 70mm and 5-screen channels. Again, I have a bit of experience there. More often than not, voices landed right on a speaker and not phantomed. When people walked across the image, then yes, there voice would move with it but, by and large, people were pretty much where there was a speaker. Look at a film like The Sound of Music...and if you have the opportunity, look/listen the screen channel soundtracks. There is less phantoming than you'd imagine. Even on films like 2001: A Space Odyssey, where it really started as a 4-track mix...they locked people over speakers. A classic scene would be in the phone booth where there are some visual edits. They actually locked the voice to prevent any jarring timbre changes when, technically, they should have swung the voices to match the edit...it happens fast enough that it doesn't immediately trigger a "huh?" sense. In the 2001 example, one of voices is locked on Left-Center (with bleed onto Left and Center...owing to its 4-track origination and "spread" into 6-track. Again, if given the opportunity, take a look at the meters during various scenes and you can see (and hear) what was going on.

I'd come back to...nobody, in their right mind, would design a cinema sound system where the main audio come from anywhere but behind the screen. And, honestly, I think three speakers has always been too few since widescreen became a thing in the '50s. 5-screen channels should really be a minimum. I've never seen a movie screen so small as to not benefit from 5-screen channels. Now, how people mix movies...that is another story. Some utilize the tools available better than others...just like with the picture.

[Bobby Henderson]

It's been about 25 years or so, but AMC used to have those torus screens that were kept in shape using suction... they had their sound system mounted above the screen. I've only ever seen one show in such a theater and I remember the screen to be pretty terrible, since it was all out of shape as that suction part apparently wasn't really working, but I don't really remember how good or bad the sound was.

In the 1990's I watched a few movies at AMC locations in the Dallas-Fort Worth metro, theaters that had those solid Torus screens. One was the AMC Glen Lakes 8, which was near the GCC Northpark 1-2 and United Artists 8-plex. It had a "HITS" house; I watched "Speed" there for a second viewing, after having watched it the first time in THX-DTS at the Prestonwood Creek theater. The sound was a bit more hollow at the AMC location.

The AMC Grand 24 near I-35E & Loop 12 also had Torus screens when it opened in 1995. Its biggest houses were fairly large, which I think worsened the hollow character of the audio. The first show I watched there was "Die Hard With a Vengeance" in SDDS. I saw that movie again in Dolby Digital at the Casa Linda 4 theater (it sounded better there). Part of the original AMC Grand 24 building is now LOOK Dine-In Cinemas. Another portion of the building was turned into a bar/music venue, which has had at least a couple different operators open and close.

The original Grand 24 theater building is in an especially odd location, which might explain why it has had such an unstable history. It's technically right off I-35E. But getting there is a little tricky. The I-35E/Loop 12 junction is kind of a mess. You have to get to the intersection with the surface street version of Loop 12 and Technology Blvd. Then Tech Blvd goes winding behind restaurant row to get to the actual theater building. If you're on the highway and miss an exit you'll do a good bit of driving to back-track.

Now, how people mix movies...that is another story. Some utilize the tools available better than others...just like with the picture.

Sound editors and mixers have unbelievably sophisticated tools at their disposal today. And it's possible to do high quality audio editing on a limited budget or even hobbyist level. Audio editing technology is so much better than it used to be.

Unfortunately with movie post production the audio mix is still being treated as an after thought, maybe even worse than ever. Not nearly enough time is reserved. Producers expect the sound mixers and editors to just bang out some shit in the very last minute. If they were given more time the paying customers might get to enjoy more creative sound mixes. A really great mix using all the bells and whistles of Atmos takes requires more post production time.

Compound that problem with so many commercial movie theaters cutting corners with their sound systems, both in design and maintenance. THX certainly had its problems, but the original concept and intention of it was a great idea. The commercial cinema industry needs something like that again. Right now presentation quality is all over the place. I have no idea how good or bad the sound is going to be, even when visiting the same theater.