I came late to the cinema exhibition world, beginning with installations and training and marketing and quality assurance in 2002 with the film to digital transition all over the EU, and even China – from Sligo to Shenzhen is the catchphrase I use. It was a great time with great people. This project is my way to give some of that back.
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History and Fate have led to this point, working in the audio recording business in the 70s during its initial transition to digital, in computer automation for audio consoles and other high end gear in the 80s and 90s, then in video equipment as it went from heavy iron to digital.
And then somehow being a projectionist at the Cannes and Venice Film Festivals in the early 2000s and making certain that systems were set up properly for a manufacture who had to report to DCI and doing bug-searches and white papers and ...wow, it has been fun.
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Please use this new site, since it will be the most up to date and it will come with new features. Thanks!
Imagine that you have joined a non-technical employee Quality Assurance Project. You might have many goals: I want to learn a bit more about the technology of movies, or, I want to be part of a well trained team that keeps customers happy… and you might have many different purposes for those goals: If I can help create happy customers, they come back more often…or, if I have good control of the basic skills, I can use them to get even more important skills, becoming more valueable to my team and company. To accomplish these goals and achieve these purposes, there are many things that need to be done.
Of course, your goals and purposes must align with the quality policies set by the CEO of the company (Cheif Executive Officer). The CEO might say that your small village theater can only get so much money for seat and carpet replacement and do the best with what we have, but we are not a premium movie palace. Or, the CEO might say, spare no expense, this is the Flagship Theater for the entire chain and it has to be the best. Or, something in between.
Usually there is a way to be true to your aspirations and stay within the boundries set by the boss. No matter what, the boss would never want us to compromise safety, or show a bad image on the screen, or let the sound get full of distortion. They probably want to make sure that each patron is satisfied with what the facility and what the staff have to offer, even if it can’t be the perfect place. So this includes wanting an educated staff that is able to communicate intelligently with patron and tech staff.
And that is what we are going to do, a little at a time – learn to communicate about the performance of the facility with the patrons, a little at a time. In this section we are going to learn about measuring light levels with simple equipment …your iPhone, right?
So, if at first you don’t have the organizational support to download DCPs onto a USB drive, then get the DCPs into the Media Player/Projector system right now – you can still download some audio and light measuring tools, and experiment with them until you can use them easily in a dark room. Continue reading 7) Measuring Light→
Please use this new site, since it will be the most up to date and it will come with new features. Thanks!
SMPTE ST-2095-1 is a new standard for Pink Noise. It took a great deal of work by a great number of clever people, a lot of listening and testing and tweaking. The cool thing is that it isn’t made with a lot of transiticators, but rather, with digits. This is THE Digital Pink Noise Standard.
Pink Noise has been one of those things that has always been around, and people don’t think much about it. Flick a switch, and there it is. But it took a sophisticated circuit to do right, and it wasn’t always implemented the same…or even well. That is much less likely now because with the standard is a python script that is very easy to implement. Continue reading What Means, New SMPTE Pink Noise…and How?→
Hey! Hi. This page is was duplicated at the Training Courses site, with new edits, at:Measuring Sound
Please use this new site, since it will be the most up to date and it will come with new features. Thanks!
Since there are many goals and purposes for this project, there are many things that need to be done. Training is high on the list. Practice should be high on the list…but who has the time!?!?
Perhaps you don’t have the a friendly tech or projectionist to
download DCPs onto a USB drive and
load them into the Media Player/Projector system and
make a nice playlist,
You can still download some audio and light measuring tools, and experiment and practice with them until you can use them easily in a dark room. Continue reading 6) Measuring – Sound→
Become more aware of sounds in the background,
Become aware of differences in the many kinds of sounds around us. And finally,
figure out what sounds are annoying to you.
Every good speaker designer has to learn these things too. Every good designer of auditoriums need to learn these things. Why? Because sound all by itself is complicated. But to make sound go through speakers and reflect off ceilings and walls (and people!), they can take classes in physics and design, and study angles and study which magnets are the best to use in different speakers that also must focus certain frequencies differently than others – all that science stuff. And, they also need to know the things that artists know. How to observe. How to decide what is pleasant, what is disturbing. Because: Acoustics, designing rooms for sound, is a science, but very importantly, it is an art.
They can design a perfect room. They can set it up with the best equipment to have perfect balance. But when they play their favorite movie scene or recording, they often listen find things that are annoying.
You do not need to know about the 10 or 20 parts for each speaker, or the details about each speaker in each speaker box, or the special wire that connects the speakers to the amplifiers in the best system. You don’t need to know details about the media player and the audio processor and the every part of those.
Putting together all the parts is an art and a science for others.
You should be aware that these things exist. You should be aware that these things can have problems. But mostly, you need to be aware of…to learn how to… listen.
We will work on
1) listening to sound. And we will also learn how to,
2) listen to audience members, and
3) how to listen well enough to fill in the audio questions of the Managers Walk Through Form.
And now, our first real technical word: Frequency.
Frequency is a term that is used when describing both sound and picture. So we will need to get a good idea of it. Let’s do a quick once over to remove a little mystery out from the subject.
Think of a song. Think of the beat. . . . . . . . . . Count that beat for 15 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .For this exercise we are going to use the number 30…30 beats every 15 seconds. That is 2 beats every second. If we counted for 30 seconds we would have 60 beats for every 30 seconds. And, for 60 seconds, 120 beats. 120 beats per minute. 2 beats per second. You can clap your hands that fast. Imagine the beat being 4 times faster…8 times every second…that may be faster than you can clap your hands.
Beats every second is a frequency. Beats every minute is a frequency too. Beats every day is a frequency, but the number may be too huge to count…and your hands would be pretty tired! But, the planet has made 1 revolution around its axis in one day…1 revolution every day is a frequency. And the planet earth will go around the sun in 365 days…1 every 365 is a frequency.
People usually say the word “per” instead of “every” when we talk about frequency. 1 revolution per 365 days. And sometimes we have to be careful – does that mean 1 revolution around the axis or 1 revolution around the sun? But with music…that is, with sound…and color…that is, with light…people understand that we are using seconds.
And, instead of beats we use the word “cycles”. Cycles are a little more fun.
When you clap, your hands go toward each other, then away from each other. They wave at each other going one distance out and then back in.
Waves are like that. They repeat their sequence. You can start counting the wave when the hands hit…the bottom of the cycle, or you can start counting the wave when your hands are farthest apart. Or start someplace in the middle. The important part is the cycle of the wave and the time. Cycles per Second. Cycles per Year. Cycles per Decade.
Cycles. Time. Frequencies.
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 the low and rumbling sounds and and go all the way up to the twinkling high notes. If you look at the longest strings of the piano as they are hit, you can almost see the back and forth slow motion vibration as they move through the air – and they act on the air – creating those low notes that hit our ears. If we look at the strings a few notes higher, they move so fast that we cannot see them vibrating.
The same is true for the guitar, which is easier to make a video of. Here is a video showing the strings moving in slow motion. Longer and shorter waves for each string…Cool! Longest waves for the bass, the low notes, the low frequencies. Shorter waves for the higher frequencies…but notice, there are more waves on the 3rd string than on the 1st string. Almost 4 waves on the 3rd in the same distance as 2 waves on the 1st. 4 waves per …something, compared to 2 waves per …something. Higher frequency, shorter wave length.
Hmmm…there is something here to study later…some reverse relationship between wave length and frequency. Let’s put that aside for later. It is just interesting, but not important right now.
So, a quick review. Frequency is the number of times that something happens, associated with a unit of time.
I saw my friend quite frequently…about once a week (for example.)
Once per second I am able to type a word…the frequency of my typing is one word per second.
The strings on the lowest note on the piano – the one on the far left – goes back and forth 27 and a half times every second. We say that it has a frequency of 27.5 cycles per second. Some of the notes in the middle of the piano go back and forth over 400 times per second – the ‘A’ note above middle ‘C’ is 440 cycles per second. The very highest strings vibrate at over 4,000 cycles per second.
Now. Why do we need to know about frequency?
Because customers will come to you and say, “The low frequency notes are buzzing.” And you can say, “Ah. Help me to understand more. Do you mean the low frequency, like the rumble of the explosions, or the low frequencies like the man’s voice?”
And your customer will think, “This person is interested and capable of getting this problem fixed – I’ll come back here!~”
Then you can tell the tech – “Yeah, like, the low frequency hits are causing some buzzing in auditorium 7. A customer told me, then I listened and it seemed like the LFE has a cracked speaker. It only breaks up on certain notes.”
The tech can now come into the auditorium with the right equipment, then find and repair the problem in a few minutes.
What was the alternative?
The customer says, “Hey. I’m watching Galaxy 9. Low Frequencies are busting up in auditorium 7.” Your new and uneducated employee falls asleep when the word “frequency” is used and forgets the customer even said an auditorium number. The tech gets a note that says, “Customer says sounds is messed up in one of the auditoriums that Galaxy 9 is playing in.” Tech comes in, has to play a bunch of stuff before hearing which sounds and what speakers are messed up. Spends more time going to get the speaker. Schedules a whole morning 3 days from now to get it fixed. Customers are unhappy.
Part 3 of Sound Basics will follow. But take a few days before you attack that. Listen to sounds again. Judge the difference between low and mid and high frequencies. Listen how most male voices are low, but not as low as many other low sounds. Be aware of your sensation of touch – how often you can feel low frequency tones on the arm of the chair for example.
Take a look at the Managers Walk Through Form. Notice the other sound questions. Get comfortable with the idea of listening for those things, at different places in the environment.
Sound Section of Managers Walk Through Form
If you are really brave, dive into the Lesson: So Now You Want To Measure Sound. Go ahead. It is a good idea to get some physical experience instead of all these theory lessons every time. (Theory lessons per week…frequency.)
And, remember these two things: No one was born with this info. Everyone had to learn it, to experience it, to mess up, to learn again, to get better then mess something else up…don’t get discouraged.
And two, keep it fun. On this path are rocks and sand and dust and great distances between knowledge. Scientists still discover things about sound and hearing, just like they do with light and pictures and vision.
Don’t forget to write questions or thoughts in the Comments or in the Contact Form. Let us know what we could explain better, or didn’t explain at all.
Hey! Hi. This page is was duplicated at the Training Courses site, with new edits, at:What’s It Mean? Distortion?
Please use this new site, since it will be the most up to date and it will come with new features. Thanks!
Hopefully you have read through the post named Basics: Audio (Sound), Part 1 and Part 2. It is good to have a basic understanding of frequencies and speakers and surround and amplifiers and level and Loudness. Hopefully you have noticed some of the many ways that the human hearing system has made things “interesting” in normal life, maybe even pointed things out to people while you walked around your cinema auditoriums since learning more about these things. Continue reading 6) So Now You Want To Measure Sound Level→
The information on this page has been transferred and updated at the Training Course page: Audio (Sound Basics): Part 1
Sound is all around us. We don’t need any particular talent to use it. Doctors tell us that we can hear sounds in the womb.
Using sound well is a different story. Being able to judge sound, to know if it is the best possible for your clients – or at least acceptable – is another different story.
For a simple definition, “Sound” is what we hear. But actually every sound involves hundreds of steps. These steps begin with a motion that takes place at one point. The drummer hits the drum, and it vibrates, the bell gets hit and it vibrates, we push air up our throats and make it vibrate.
Hey! Hi. This page is was duplicated at the Training Courses site, with new edits, at:What’s It Mean? Distortion?
Please use this new site, since it will be the most up to date and it will come with new features. Thanks!
Let’s do this again. We will go through a term that everybody uses but which has a different meaning depending on who you talk to. Which meaning do we care about? The meaning that will correctly get an idea across to the Tech Team. We must describe a problem so it can solved quickly and well.
Distortion – For our purpose, distortion is the term that describes the imperfect recreation of the original sound of the motion picture. There are other definitions and uses, including the use with picture details such as ‘brightness and contrast problems’ or ‘focus problems’ or different kinds of color and screen problems. Continue reading 9) What’s It Mean? Distortion??→
Hey! Hi. This page is was duplicated at the Training Courses site, with new edits, at:What’s It Mean? Distortion?
Please use this new site, since it will be the most up to date and it will come with new features. Thanks!
Let’s do this again, go through a term that everybody uses but which has a different meaning depending on who you talk to. We care about the particular meaning that will correctly get an idea across to the Tech Team. We have to describe a problem so it can solved quickly and well.
Distortion – For our purpose, distortion is the term that describes the imperfect recreation of the original sound of the motion picture. There are other definitions and uses, including the use with picture details such as ‘brightness and contrast problems’ or ‘focus problems’ or different kinds of color and screen problems.
Sound problems can be detailed too – for example, ‘too loud!’, or ‘too soft in one area of the room or one set of frequencies, like the ‘bass being too low’ or ‘a rattle that occurs when a loud noise happens onscreen’. But for many sounds we cab just say it is ‘distorted’ and let the tech figure the exact cause.
Here is a sample of 3 bell sounds. The 2nd is purposely made jagged, and the 3rd imitates a blanket on the bell. Most people would call the 2nd one distorted, and the 3rd one muted.
Another difference between sound distortion and picture distortion is that we generally know what a face or pair of shoes should look. But we don’t know how the warp plasma-drive should sound when it is having problems, or how rich an orchestra is supposed to sound in the side speakers – maybe they are supposed to be lower on one side or the other.
We really don’t have a way to know if something is being played back correctly. Maybe the director wanted the sound to be “dark” or “jagged”. We in the cinema were not there for the recording or post production mix. But generally we can presume that gross cracking and ugly sounds are not right.
Here’s a speaker that tried too hard, broke apart, and will now sound horrible – gross cracking and ugly (if it makes sounds at all!)
If you ask any sound mixer, they will say something like, “We mix the dialog so that it sounds like the natural level for the person speaking in the scene. Then we mix the music and sound effects around that so that everything can be heard.”
Statistically, something like 80 or 85% of the dialog comes from the center speaker. The rest is mixed in the center and left or the center and right speakers.
So, we know that if the dialog doesn’t sound natural and if it is coming from one of the side surround channels, that something is probably wrong – and should be reported.
What does it mean, ‘natural’?
That is a great question and the answer is amazingly simple and amazingly complex.
Human languages are incredibly complex. There are some parts of words that you can throw away and no one notices.
but there are some sounds that, if they go missing, the word doesn’t sound like a word – or maybe it could be one of 20 words.
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Please use this new site, since it will be the most up to date and it will come with new features. Thanks!
As usual, the first question for every “What Does It Mean” topic is: Why Do We Care?
Every Answer begins the same: there are many things that can go wrong with the presentation of the moving picture. In this case, we are working with how much dark and how much bright there is on the screen.
This one is a very tricky. The image is onscreen. In most cases, the images may look OK if you just glance at the image, or if you don’t know what to look for.
Will the audience care? Maybe not. They don’t know what “Correct” is. They will think that the picture lacks “Pop”, or some other quality. But if you don’t know that the black suit is really supposed to have fine light blue lines in it, then the black suit might look OK.
We will show the definition of these terms with examples of how they apply to our situation as someone who is checking the quality of the picture. Don’t look them up now since they have many meanings and most are more complicated than we need.
Complication: Almost all cinema projectors have a problem creating perfect blacks. But there is a range of deep blacks and deep grays that they should create without problem.
And white too! Perfect white is never shown – it would ruin your eye’s ability to notice differences between things when the picture is too bright.
Which is the problem with Contrast…too bright, you can’t see details in the darks. Too dark – muddy – you can’t see the detail in the bright.
There needs to be a good range – when you look in the dark, in the shadows, there should be richness in the dark reds and and dark blues and and dark greens and and greys. And when there is is bright scene, there should be good pastel colors too.
Another problem is – We don’t always know what the artist wanted – a lot of movies are ‘moody’ and ‘dark’. But even dark movies shouldn’t be mushy.
Potential Points of Failure: Bad setup on the Projector. Wrong Lens. Port Window, if very dirty. Old screen. Dirty screen.
Look at these three versions of the same winter scene at Yosemite Falls in California.
In the first one, you can see the amazing falls against the crisp rocks, and the golden hour sun is beautifully lighting up the mountaintop.
In the 2nd one you can almost taste the frost from the frozen lake. The air is so crisp and clear that you can see several layers through the trunks of the trees. If you hadn’t already seen the gold in the mountains, the 2nd picture would be OK.
The 3rd is in between…not as on fire, not as clear through the tree trunks…dark in fact. The falls don’t stand out as sharply against the rocks.
By now you may have guessed, the 3rd one is the one that the artist created. The difference in the three is entirely the level of Contrast.
So. What is Contrast?
Simply, in the cinema, there is a level of white and a level of black. Outside, on a sunny day, the level of bright can be 30,000 or perhaps up to 120,000 at the brightest day at the brightest time in the brightest place…and reflections on cars…they can be 10’s of thousands of bright too! And, the level of black? Wow, a dark night sky in a forest when you can’t see the hand in front of your face – a single candle will seem very bright indeed. Let’s call a candle at arms length 1. Move the candle away and it becomes .1 and .01 and .001. In theory, our eyes can still see that candle on a perfectly dark and clear night when it is many miles (or kilometers) away.
Move the candle close to you, or put several candles in your hand…or a light that has the power of several hundred candles …well, at some point you get too much light in your eyes and, in protection, they shut. And inside the eyes, in protection, there is a protection mechanism as well.
But let’s not get off the point: Contrast is the difference between the highest level of bright and the lowest level of dark. If black is 1 and white is 2,000, then we say the contrast is 2000 to 1. It is written like this – 2000:1. When it is written like that, it is called the Contrast Ratio.
Why do you need to know that?
You want to have a good feeling about your ability to notice good and bad contrast. And, most importantly, how to tell the technician what you see when there is a problem.
We give a little more detail about these things in Part 2, with more examples.
But first, take a break. The exercise for this lesson is to look in shadows while you are living life.
Notice: there are important details to see in the shadows. Look under tables. Look into the dark and notice how colors shift down to black. You might have to purposely shade your eyes from a bright light.
And: Notice how there are things to see even in light that is almost too bright to look at. The colors will be softer in bright light, even for the same shoe or car or face that was a deep rich color when you saw it in the dark.
When you have experience and a good feeling for these ideas of Contras, click into Contrast – Part 2
