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T351 Week 2 (Tues) Summer 2014

Agenda:

  • Lecture today: Audio & intro to field lighting with reflectors. Did you finish the Week 1 readings? It's time for Week 2 (sound).
  • Carry out Audio / News Exercise. Try to capture & rough edit your footage before tomorrow/Wednesday's lab. Tomorrow I'll take you through a quickie Photoshop Exercise.
  • Tuesday/today turn in the following via Oncourse:
    • Storyboard critique
    • Audio/News Exercise topics/questions/intro script
    • Art Video P. Proposal & Treatment (You may start shooting these anytime after you turn in your pre-production work.)
    • Interview/Feature Story P. Proposal & Treatment (who, what, when, where, questions etc.)
    • Drama/Storytelling Pitch, Logline & Treatment due (Scripts not needed- just treatments)
    • Final Project P. Proposal Due
  • Lab Wednesday - Pitch Drama/Storytelling Ideas. Cover continuity & graphics. Will have a little time to edit & review the Audio/News/Reflector projects.
  • Lab Thursday - No Lab! This time is dedicated for you to shoot your Art Videos
  • Next week we'll cover lighting & you'll shoot your interview/feature stories.
  • Recap Storyboard/Continuity Exercises. Wow! On the whole these were strong. Most likely the strongest set I've ever had in a T351 lab. Some of you had some very interesting/unique/artistic scenes. A few had minor issues

Notes from looking at the Camera Acquistion Exercises:

  • Use a tripod! If you do go hand held, STAY WIDE.
  • About 4 people had WB issues. Be sure you know how to use a built-in preset WB setting (E.g. indoor or outdoor) and also how to manually set it (A or B).
  • Exposure: Do you know how to set proper exposure (Zebra stripes)? The ND filters are usually required on a bright, sunny day. If in doubt it's better to underexpose rather than overexpose.
  • Technical - a few didn't turn in the project in a format that it was slated. (They turned in SD and 25 fps when slated HD 1080/60i.) Be sure to maintain HD and your frame rate throughout the process of importing, editing and outputting.
  • Always strive for strong composition (balanced frame, depth, etc.)
  • Don't forget to record pre-roll and post-roll.
  • Focus: Is your viewfinder in focus? Remember the diopter adjustment underneath the eyepiece and the expanded focus button (near the servo zoom rocker). I almost always use this when shooting anything besides wide shots.

On writing Treatments for non-fiction:

Here's the start of a sample treatment for a bio piece, "Sally Jo, MFA Sculptor"

Scene 1 - Introduction

Open with montage of extreme artfully shot close-ups of ceramic pieces cut to the rhythm of acoustic fingerpicking guitar music. After 10-15 seconds of images and music, Sally Jo's voice comes in, describing the kinds of art she aspires to create. After a few seconds of voiceover Sally Jo can be seen, seated in her studio. She describes what got her interested in making fine ceramic art. An identifying graphic is keyed on screen.

Scene 2 - The Process

Cutting back to the close-ups of ceramic pieces, Sally Jo describes the process for picking colors and crafting her designs. Cutting out from the close-ups, we see that these are sitting on shelves in a studio. Its Sally's studio. As Sally's voiceover continues on about the design process, she enters the studio and begins to craft a piece out of raw clay.

etc....

Video producers are like attorneys. During the interview/questioning process you pose questions to draw out specific content. If you are good and have prepared, you have a pretty good idea of what the answers will be.

Just on the two scenes in the above example you can extrapolate the questions needed:

  • Q1: Describe the kind of art you aspire to create.
  • Q2: Describe what got you interested in ceramics.
  • Q3: Describe your design process.

SOUND - (Readings: Cybercollege units 37, 38, 39 & 40)

Components

  • Introduction
  • Loudness & Frequency
  • Types of microphones and their application
  • Signals & metering
  • Examples (music, close up miking, long shot miking, ambience etc)
  • Lab assignment:

Introduction

Audio for film and video is more than just recording a good signal. Most soundtracks are multi-layered creations that go far beyond providing us with dialogue from our performers. We hear cues that tell us where they are- outside, inside, who’s sitting on the left or right, how big the room or environment is. How many people are milling about in the background and what they are doing? Maybe what the weather is like.

You could place two people at a table in a restaurant set and record pristine audio with a $2,000 microphone. It might sound great, but it’s not going to fly with a TV audience. It would sound weird. Viewers expect to hear clinking silverware, the murmur of other diners and music playing over the sound system. A classy restaurant on Friday night would sound much different than a diner on Saturday morning.

If you need backgrounds or sound effects for your production you have a few choices. The production lab has a sound effects library that we share with WTIU. You can also record background sounds yourself with the camera (it does have digital audio).

We'll cover specific tips and techniques in lab.

Stereo imaging & perspective

More and more people have surround sound systems or at least listen to their TVs in stereo. The audio playback you have at home is likely far better than what we have at our edit stations.

Viewers expect audio from people on the left side of the frame in a long shot to come from the left side speaker in their TV sound systems. Take a two shot of our couple at a table in the restaurant. The audio from the person on the left comes from the left side speaker. But then we cut in to a full screen close up. The sound then comes from the middle. To further complicate things, we (sophisticated viewers with surround sound systems) are used to having the audio perspective match the camera perspective. At a long shot in the restaurant we expect to hear more room noise- more diners and waiters walking by. Think about the production logistics involved in this. Then we cut in to the two shot. It sounds closer. We cut in to the close-up. It sounds closer still.

This is why the boom mike is often favored over lavalieres for recording dialog. We can easily vary the distance so the audio perspective matches the camera perspective.

Loudness & Frequency

Loudness can be measured in decibels (dBs) and be represented visually with VU meters.

Metering & Level Setting: Analog vs. Digital

The scale on a VU meter goes from –20 db to +3. We set the levels so most sounds are underneath 0 with the peaks going up into the red area.

Common practice is to use a 1 kHz tone at 0 on the VU meter for reference purposes. For example we always record color bars at the beginning of tape. It should be accompanied with 1 kHz tone at 0 VU.

In digital audio, there is absolutely no headroom over 0. So to avoid the signal becoming clipped, we must set our reference tone somewhere below 0. How far below 0? Well it depends on a number of things, namely how much headroom you'd like to keep. There are several accepted levels for setting the standard, 1 kHz reference tone: These include –20, -18 (most common) but -14 is also used.

Just because a meter is digital doesn’t mean it’s for digital audio. Look at the numbering scale to determine if it’s for digital or analog audio.

AGC

Automatic gain control circuits try to get a consistent level. If it’s soft, it’ll boost the signal. If it’s loud it’ll turn it down. Don’t use it! It’ll bring the noise floor up and reduce your dynamic range.

Frequency is measured in Hertz or cycles per second

  • Hertz = CPS cycles per second
  • Kilohertz (kHz) = 1000 Hertz
  • Human hearing generally ranges from 20 Hz to 20 kHz
  • Concert A = 440 Hz
  • Middle C is 261.63 Hz
  • The human voice ranges from about 100 – 9,000 Hz

Microphones

Microphones convert one form of energy to another: sound waves to electric energy

Microphones can be classified by their electrical characteristics and polar pickup patterns.

Electrical Characteristics:

Dynamic - Works opposite of a speaker. A wire coil attached to a diaphragm is suspended inside a magnetic field. Sound waves hit the diaphragm making the coil move. This creates a flow of electricity in the coil windings. Dynamic microphones are typically durable and a good choice for hand held vocals or percussion instruments.

Condenser - (a.k.a. electret or capacitor)- Need batteries or pha6ntom power to operate. A plate or diaphragm moves adjacent to a stationary, charged backplate. The capacitance between the two plates changes as the diaphragm moves modulating an electric current. This current must be boosted by a preamplifier to create a usable signal.

Condenser microphones are more sensitive and create a “hotter” signal. They are a better choice for distant miking and lower level sound sources. Most full range, high-quality studio microphones are condensers. You must either use batteries or phantom power. Phantom power is 48 volts, which is sent up the microphone cable from the mixer or camera. (Most professional cameras – like the JVCs have phantom power)

Ribbon - A small (extremely delicate) metal ribbon is suspended inside a magnetic field. Sound waves move the ribbon, creating an electrical flow. Because of their delicate construction, ribbon microphones are not suitable for windy conditions or extremely loud sound sources. They are typically only used for vocal applications. (The RCA mike on Johnny Carson’s desk was a ribbon microphone)

Piezoelectric (a.k.a. crystal) - Some materials produce voltage under pressure. Mainly used for contact microphones and music instrument transducers (E.g. guitar saddle pickups).

Pickup patterns:

  • Omni - Picks up equally well in all directions. (EV635 is a rugged and inexpensive dynamic mike. Most lavaliere microphones have omni-directional pickup patterns)
  • Cardioid - Has a heart-shaped pickup pattern. Dynamic cardioids include the SM57 SM58 & the RE20. Condenser cardioids include AKGC100, AT4033.
  • Hyper-cardioid (Shotgun microphones- almost all are condensers)
  • Figure eight or bi-directional (All ribbon microphones. The U87 & AKG414 are switchable between cardioid and figure eight)
  • Boundary or Pressure Zone Microphones (PZM) are flat and designed to be placed on a flat surface. Their pickup pattern resembles half of a sphere.
  • Contact microphones are small and designed to be mounted directly onto a resonating object. (Onto the bridge of a cello or the inside of a guitar) These are used mostly for music.

Applications:

Lavaliere (wireless are the norm) Very popular for film & video. Provide a consistent sound close to the source and are inconspicuous. Wireless versions of these are a must have for professional videographers.

Hand held – try to avoid using these unless you’re doing interviews with people on the street (an assistant with a boom would be better). When using, make sure to keep them a consistent distance from the source. The best hand held microphones have internal shock mounts.

Stands (floor & desk) obtrusive good for music; desk: obtrusive but an excellent way to hold a microphone (Leno, Letterman)

Boom – handheld and floor stand models (typically used with a shotgun mike)

Headset – Conspicuous but provide audio monitoring for performers and a consistent sound source. (Used frequently for live sporting events and by singers)

Parabolic mount. A large bowl with handle on the outside and a microphone mount on the inside. Place a microphone in the middle and you have a highly directional microphone- more directional and sensitive than a shotgun mike. Commonly used for sporting events and spying, be sure you faithfully listen to the headphone while using. You need to move these continuously to keep them focused.

Signals, cables and connectors

Mic / Line Level - Audio signals are typically either line level or mike level.

Different line levels (+4 dBu & –10 dBv). There are two different levels considered "line level". Professional equipment uses a slightly hotter signal of +4 dBu. Consumer equipment (such as CD players, VCRs, etc) uses -10 dBm. They are usually interchangeable, but plugging a +4 output into a -10 dBm input will sound louder and possibly clip or distort. Plugging a -10 dBm output from a piece of consumer gear into the +4 input of a mixer will usually work fine, except the signal might be slightly softer.

Balanced vs. Unbalanced - Audio cables are either balanced or unbalanced

Balanced cables have three wires (two conductors & a ground) and are far less prone to electrical interference than unbalanced (2-wire) cables. Long cable runs of unbalanced cables will also cause a loss in high frequencies.

The cables that connect your home stereo equipment together (with RCA connectors on the ends) are unbalanced lines. They only have two wires, a conductor and a ground. The cables with XLR connectors on the ends (like mike cables) are balanced. They have three wires- two conductors and a ground- that’s why they have three pins or plugs on the connectors.

Balanced lines are less likely to pick up hum and distortion than unbalanced lines. You can use them on long cable runs without audio degradation. Unbalanced lines are likely to pick up radio interference and lose high frequencies on long cable runs.

Running cables - Don't run cables adjacent to AC power cords. Keep them separated as much as possible and cross them at 90 at intersections.

Learn to wrap cables! You need this to work professionally- really. Will cover in lab.

Wireless microphones - Diversity vs. Non-Diversity - Diversity receivers have two antennas.

Compressors - Used to reduce the dynamic range (loudness). Digital audio has a great deal of dynamic range (signal to noise). Unfortunately we often need to reduce the amount of dynamic range to make the audio signal more suitable for analog tape, TV broadcast or for radio transmission.

Compressors let you select a threshold level. Sounds louder than the threshold are compressed by an amount that you can specify. You can also set the attack and delay of the compression.

Audio that has been compressed sound can be louder than non-compressed audio. Reducing the overall dynamic range creates less variation in the signal. In other words, the difference between the loud and soft portion is reduced. With a more consistent audio level, the overall signal gain can be increased.

Limiters - They reduce the dynamic range (like compressors), but can totally limit the signal, not just reduce it.

Expanders - The opposite of a compressor. Sounds above a set threshold are expanded, or the gain is increased.

TIPS

  • In general, shotgun mikes on stands or boom poles, or lavaliere mikes work great for interviews.
  • Never use AGC unless you have no other option (shooting breaking news, covering a fire, etc.). If you do, use one channel set for AGC and the other on manual.
  • When shooting B-roll or any video, always record audio- even if you don't think you are going to use it.
  • When shooting interviews you can use one track for your subject and the other for either your interviewer or just NAT sound from the camera. (Sometime I record the subject with two mic- a lav AND a shotgun mounted on a stand outside of the frame.)
  • On location, always record some ambient audio with the same microphone you are recording your interview with. (Often called room tone.) This can be layered into the soundtrack during post. If you need to add some dialog to a scene, you’ll have a background bed to lay under it.
  • When scouting shooting locations listen. Is it quiet enough? (vehicle noise, construction)
  • Faithfully monitor your audio with closed ear headphones while shooting. Listen to both tracks. Listen for drop-outs, popped Ps or Ts, and any other distortion. Record a little and play it back. If you are in a noisy environment, go to somewhere where you can hear it.
  • Make sure you don’t record any copyrighted music in the background.
    Use the same microphone for your voice-overs as for the on-camera.

Microphone techniques

Setups to ponder. How would you record the following:

  • An on-camera news announcer? (In the field? Anchoring behind a desk?)
  • An interviewer with a guest?
  • Three people having a roundtable discussion at a table?
  • A dramatic scene in a house with lots of action & movement?

There is no single "right" way to do any of them. What you choose will depend upon your level of skill and available equipment. The Telecom Dept does have stands, additional microphones and field mixers you can check out.

Reflectors

These should be in every photographer/videographer's gear bag. Look at samples:

 

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