Category: Entertainment Technology

Catchall Category

Checking Color Without a Meter

During the first minute of the Faces DCP, the screen shows a black background with a blue bar going across the middle. After a while the black background goes grey on one side. You’ll notice when you look at the two ends of the blue bar now that they look different – one more solid blue, one softer. When the background goes solid black, the bar looks solid blue from end to end again.

When we walk into the auditorium to do our task attempt to judge whether the picture quality in an auditorium is correct, we have to be aware that the Human Visual System can be tricked.

Perhaps that is the wrong way to say it. In fact, the Human Visual System uses tricks to get around the limitations that it has. One example is the number of color sensors we have in the eye. For many reasons, we have 100 million sensors squeezed onto the inside of each eyeball. But only about 6 million are sensitive to color. On average, 4 million are sensitive to red light, 2 million to green light, and only a few hundred thousand are sensitive to blue light.


The major idea behind the two Faces Test DCPs is that the Human Visual System and the Human Hearing System work magic. To test the picture in your auditoriums, we have to somehow get around that magic.

One part of the magic is that people’s eyes adjust to different light levels. We have the ability to see in dark moonlight and in bright sunlight. We can see great detail in our center vision, and we can see minute motion in our side vision. The eyes and the brain work together to give the best image possible in different circumstances.

We hear sound in a similar way. In a quiet room we can here a fan or even a mosquito that is 3 meters (10 feet) away. In a loud kitchen, we can hear voices that are softer than the loud pots and pans. (Well, sometimes.) We certainly can’t hear that mosquito among the kitchen noises. And we can’t see a dark cat go by in the shadows if there are headlights making the the scene too bright.

Usually this magic is a great thing. It is an automatic process that protects the eyes, yet lets us see through an incredible range of light in the right circumstances. But it also means that when we see leaves of green and fields of rice waving in the wind, we presume that the clouds are white and the sky is blue …but they might really be grayish white and a light shade of blue.

This especially happens in a movie theater. The sun or reflections that we see outside are hundreds, even thousands of times brighter than a projector can display on the screen. Yet, we believe it is bright white. And that is what matters to the audience. But we have to check that the projection system is giving all that can be expected, not wimping out or giving too much of one color or not enough of another.

Sound is the same way. It is a rare person who can hear a tone and accurately say with certainty, “That is the note ‘E’ below middle ‘C’ on the piano for example or that it is soft or loud. All we can say is that it is soft or loud in comparison to something else.

Our purpose is to test the system, to see if it has the right amount of light (and sound). How do we get around this amazing capability of the Human Visual and Hearing Systems?

One thing that people can do very well is determine if faces look right. So, your author went to a photo sharing site and dropped a bunch of faces on top of each other and made two DCPs. We think it turned out to be a very interesting way for you to judge the quality the projected pictures on your screen. And, like the other DCPs, there are also clean and distorted and muted high and low notes to judge the quality of your sound. Oh~! and let’s not forget the subtitles…

The passcode is QA_b4_QC

Here is a quicktime version of the Faces1 DCP – Have fun, and tell us what you think. With your help we can make a system that helps you tell the tech what is wrong and eliminates the complaints of the audience member.

Emergency You

We work on the theory that a large percentage of people who get a job at a cinema do so to get an entry into Entertainment Technology. Shhh…It’s OK; we won’t tell anyone.

Entertainment technology is quite interesting and has been very good to a lot of fun people. Just don’t tell anyone that training you is all that we are really interested in. The industry needs interested and interesting people. Start out being interested about everything and soon you will be interesting.

There is nothing wrong with someone just taking a gig because you need the cash, or any other reason, of course. But, if you are interested in how all of the equipment around you turned from ideas into reality, keep doing well.

What does that all have to do with The Emergency?

Well, unfortunately, with more knowledge comes more responsibility. And no matter how one may try to prevent panic-inducing moments, sometimes they will happen.

At that moment it is knowledge and practice that needs to kick in. To panic gracefully when others around you are stunned or reaching the wrong conclusion about what happened or what needs to be done.

That is the point of this Series. Is the equipment in shape? What equipment? There’s a list somewhere right? Has it been tested, has it gone passed some due date even when its valve shows it is in the green?

This article is unfinished, waiting for someone with the time and ideas to put the finishing touches on…is that you?

4c – Audio (Sound Basics): Part 3

Hi again. This is a work-in-progress…do not read yet.

At the very end of Audio (Sound Basics), Part 2 we introduced the concept of Frequency when discussing waves. We also mentioned some basic information about the speakers in the room, which create the waves that we eventually hear. This article will build from there. You can skip all of this and you can still talk to a technician, but it is really simple. It just looks long because there are a lot of examples.<!–more–>

It was said that we can think of sound like the waves made by a falling pebble on the surface of a pond. This isn’t exactly true, but that is the trouble with analogies – they are similar by not exact. At least you can see a wave in water. A sound wave, not so much. So, we’ll proceed with this analogy as far as we can and explain the difference later. Because we have to learn about sound, and sound is made of waves that are created by the speakers.

So, the experiment is dropping a marble in a pond from the same height each time. If we look closely at the expanding waves, we will notice that the first wave is always taller. As the wave moves away from the source point it gets shorter and shorter. But, while we can see it, the distance from the peak of one wave to the peak of the next stays the same.

What we are seeing is that the power is getting distributed around the water in the circle, so the height goes down. But while it was happening, the number of waves going past the place you were looking at was constant. If we could look while also measuring time, we would notice that the number of waves that go past in the first 5 seconds is the same number of waves that go past in the next 5 seconds.

The distance between the peaks of the waves is called the Wavelength. The number of waves every minute or waves per second is called the Frequency. These two are completely related – as the number of one goes higher, the number of the other goes lower. The higher the Frequency – that is, the number of waves going past per second or minute – the shorter the peak-to-peak Wavelength. And, the opposite; the lower the frequency, the wave length is longer.

An easier example of these opposites is waves at the beach. If we see them crashing to the shore at 15 a minute, we can probably look into the distance and see several waves coming in. (High frequency, short wavelength.) But if you see the surfer who has to stand on her board to see the next wave – that is, the peaks are very distant, that means they have a long wavelength, and sure enough, there is a low frequency – you will see that there are only a few waves per minute crashing on the shore.

You can almost see this with a piano or guitar or harp string. When the low note is hit or picked, the string travels back and forth so slowly that you can practically see it (although, no matter how fast I can count, I can’t keep up.) But the actual sound wave that it is generating is very long. For example, the low note on the piano moves back and forth 27.5 times every second – we say 27.5 cycles per second. The wavelength – and you’ll just have to believe the science people on this – is over 10 meters long…over 33 feet!

And, here is the important part – you can pound on that note hard or soft, but the frequency of the strings and the sound will be the same…and the wavelength will be the same! And the same is true of a high frequency note, which might have a wavelength of only 6 inches (.15 meter), and a frequency of 2,500 cycles per second.

So, let’d end Part 2 here. Just one more silly thing.

Mr. and Mr. Hertz raised a very clever son who figured out that the theories of a very clever guy from Scotland named Maxwell were probable. The theories were about electricity and magnetism in a time when they were both considered spooky actions at a distance. It was a classic example of what Issac Asimov meant when he said “Any sufficiently advanced technology is indistinguishable from magic.” Anyway, his work was all about understanding waves and you will hear (or read) “cycles per second” called Hertz (abbreviated ‘Hz’), or kilohertz (kHz is the formal abbreviation, but the slang abbreviation is just ‘k’ – so you’ll hear, “The explosion had no sound above 1k”, meaning, there were no high frequencies above 1,000 Hz (kilo- means ‘thousand’)

Next we will tie these all together, add a little power and figure out what these terms have to do with your auditorium.

 

 

 


If we hit a bell with a hammer, it goes ‘bong’ or rings with a high pitch, depending on how it was made. If we feel the bell while it rings we can feel it vibrating back and forth just like the guitar string.

 

In and out, not up and down.

The height of is not the frequency of the wave. The height shows the power of the wave – the force of the energy that is expanding outward from the source point. The frequency is the number of waves that go by a certain point in a particular length of time. The frequency can be the same even if the waves are taller or shortLike the piano strings or a guitar string being struck, we measure sound in wave cycles per second. In this case it is like the water wave, a cycle is measured from the when that top of a wave passes a point until the next top of the wave. If our eyes were able to see the string move as it goes back and forth, it would be a complete cycle from left to right to left again.

When we talk about sound waves, we talk about power as intensity or volume – how loud something is. And that is where we start talking about the son of Mr. and Mrs. Bell.

Basics: Audio (Sound). It is good to have a basic understanding of frequencies and speakers and surround and amplifiers and level and Loudness.

Frequency is a term used when describing both sound and light, so we will need to get a good idea of it. Sound frequencies are very easy to think of when we consider a musical instrument like the piano. From left to right, the notes start with bass and

There are two reasons for this: power and clarity.

Power is simple. The auditorium is large and the sound must get to all of the audience without being too soft for some and without being too loud for others.

The Other-Abled, and You

There’s a funny thing on the internet that lets people in public service jobs know how to deal with those who are disabled – those poor disabled people who have no ability to use Braille or sign language in this case!

What to Do when You Meet a Sighted Person

Sighted people tend to be very proud and will not ask directly for assistance. Be gentle, yet firm.”

Calmly alert the sighted person to his or her surroundings by speaking slowly, in a normal tone of voice. There is no need to raise your voice when addressing a sighted person.”

OK;  jokes aside. We are in a service business, and we get a lot of practice dealing with people who can walk strait to the proper line without assistance, but we don’t get a lot of practice dealing with people who need different kinds of assistance.

Does that blind person get a benefit from using Closed Caption equipment? Uhm…probably not. Audio Description equipment? Yes! Probably, yes. Should you ask? Good idea.  Continue reading “The Other-Abled, and You”

Monday CleanUp

Do this to make sure things don’t get out of hand…

Monday Clean Up – 15 Minutes

Grab the dusting feather thing, and while you make certain that nothing is on top of any rack or projector, give a quick pass to keep the dust down.

Don't clean the port glass, but note down which ones are dirty.

The same with the lenses – should a task force be sent to clean them or the 3D equipment?

Dust on the port window and lens can cut down the light level on the screen by 10%. Wasted electricity, and sad customers.

I did these things. I dusted and noted what areas need more attention.
Things that need attention