One of the problems that the industry has is how to fill these theaters or “getting butts in the seats” as they say.  Traditionally an IMAX or Large Format Film is about 45 minutes in length and is some form of documentary film taking us to places we have never been before, or cannot go to.  Outer space is a great example.  However with more IMAX theatres showing up as part of the mega multiplex, theatre owners have resorted to showing standard films on the big screen.  They either blow up the image and present a very grainy film or only fill up a very small portion of the screen and let the audience view what seems like a “postage stamp” compared to the screen size.

To address this problem IMAX has develop a Format Conversion Process called DMR (Digital Re-Mastering).  The process starts by converting a 35mm frame into digital form at very high resolution, capturing all the detail from the original.  The proprietary software mathematically analyzes and extracts the important image elements in each frame from the original grainy structure to create a pristine form of the original photography.  This is the most complex step in the IMAX digital re-mastering process.

To create the brightness and clarity that audiences have come to expect from the IMAX experience, IMAX uses a proprietary computer program to make the images sharper than they were originally, while colors are adjusted for the unique technically superior characteristics of the IMAX screen.  The completed re-mastered film is then transferred onto the world's largest film format, 15-perforations 70mm.

IMAX has always delivered incredible six channel multi-speaker sound that helps put audiences in the picture and now it has re-created this immersive experience for IMAX DMR.  IMAX DMR re-creates each film's original soundtrack, adding another sonic dimension to upgrade the original movie soundtrack to IMAX standards.

Other Films that have been converted by the DMR process include:

-           Apollo 13
-           Star Wars Episode II: Attack of the Clones
-           The Lion King
-           Beauty and the Beast
-           The Matrix Reloaded
-           The Matrix Revolutions
-           Harry Potter and the Prisoner of Azkaban

Having had the chance to work on a number of film post-production studios, the standard quality of the multiplex cinemas has been very disappointing to us - the quality bar is just to high.  We have seen how you should be able to hear and see a film.  Spiderman 2 in DMR on the big IMAX screen is as close as it gets to being at the studio!

Once you have chosen a room for teleconferencing, it is important to have it evaluated by an acoustic or audiovisual engineer.  The goal is to optimize the acoustic quality of the room, making the conversations more intelligible for both your group and the people at the other end of the line.  You may not know it, but there are several things lurking around in most conference rooms with the power to wreak havoc on your audio.  These are known as STC, NRC, and NC ratings.

The first, STC, stands for Sound Transmission Class.  This rating basically describes how soundproof your room is.  The higher the sound isolation between one room and the next, the higher the rating.  Construction of thick walls and a thick ceiling have the greatest effect on blocking exterior noises and boosting your conference room’s STC.  This rating is especially important if you are as concerned about sounds (such as private conversations) being heard outside the room as you are about noise coming in. 

The second rating, NRC, stands for Noise Reduction Coefficient and deals with how much sound the materials on the walls and ceiling inside the room absorb.  Vocal echoes that may sound slight to you will be picked up by your microphone and amplified for those on the other end of the teleconference.  The reverberation you hear in the room is really just a series of echoes building up until you cannot distinguish their source.  Parallel walls made of hard materials are the most common source of these unwanted echoes.  Rectangular rooms can also cause this problem by allowing sound from one end of the room to reflect back.  One solution for defeating this type of echo is to “color” the sound in the room.  This is achieved by covering portions of the ceiling or walls with slot finishing and perforated metals or woods.  Another source of these echoes is glass.  Large windows facing lobbies or looking over a skyline should be covered with cloth drapes to dampen sound reflection.

The last rating, NC, for Noise Criteria, indicates the level of background noise present in the room.  This noise is usually made up of sounds that we have learned to tune out: computer fans, a nearby elevator, the rumble from air ducts, and many other commonplace office noises.  While you may be blissfully unaware of these sounds, your microphone isn’t.  This background noise will be transmitted to the other group and provide an unnecessary distraction that runs the risk of masking your voice.  Close coordination between audio consultants and design/construction teams can identify and reduce the sources of this noise.

When you are convinced the conference room is at its acoustic peak, the final step is the installation of the microphones and loudspeakers.  Luckily, this is much less involved than creating the room.  The main thing to remember is that the microphones should be between one and three feet from the person speaking.  If there is more than one person speaking, use more than one microphone.  In those cases, it’s a good idea to also install an automatic microphone mixer.  These are designed to activate only the microphone closest to the person speaking, eliminating the problem of several voices being transmitted at once.

While mounting a microphone on the ceiling may make the room appear more attractive, it puts the microphone out of its effective range.  To make matters worse, most loudspeakers are ceiling mounted and their sound waves have a more direct route to the microphone than a speaker’s voice.  Once the sound of the loudspeaker is picked up by the microphone, it travels through the system in a cyclical route while being amplified.  The resulting high-pitched squeal is known as feedback.  Anyone familiar with the
annoying screech of feedback knows that once it begins, the conversation ends.

Another important thing to keep in mind is that a problem called “acoustic echo” occurs when teleconferencing in full duplex mode.  Full duplex mode is when both parties are able to talk at the same time, like in face-to-face conversations.  To do this, both parties set their teleconferencing unit on Full Duplex Mode.  This leaves their mics open and speakers on, which lets the audio signals travel in both directions at once.  The problem arises when the sound from their loudspeakers (your voice) is transmitted through their mics.  Hearing the delayed sound of your own voice returning through your loudspeakers can be quite confusing.  To remedy this, a device called an echo canceller can be used.  An echo canceller looks at the audio coming through the loudspeakers, compares it to the audio going into the mics, and eliminates any matches from the transmission.  To effectively cancel out “acoustic echo”, these units should be used at both locations.

The Computer History Museum is located in the south bay just off Highway 101 at 1401 N. Shoreline Boulevard.  It is the world's largest and most significant history museum for preserving and presenting the computing revolution and its impact on the human experience. It allows you to discover how computing became the amplifier for our minds and changed the way we work, live and play. The exhibit portion of the Museum spans history from pre-computing to supercomputing, and reflects the development in technology from gears to vacuum tubes to exotic semiconductors.  It features more than 600 artifacts including the Honeywell "Kitchen Computer", the Cray 1, the Johnniac and an Eniac rack.

Q.   I have been told that installing an automatic microphone mixer in my sound system will eliminate feedback.  Is this true?

A.   No!  The complete elimination of feedback is a myth about automatic microphone mixers.  Installing an automatic mixer will help control feedback by increasing the volume of the sound in the Public Address before it starts to ring.  But how much louder the sound system can be turned up will be determined by the number of open microphones connected to the sound system.  Every time a microphone is activated or turned on, the sound from the audio system in that room will also increase.  Ideally, we only want to turn on the microphones that are needed for the communication between the individuals talking.