header
gray shim

T356 Week 5 - Fall 2014

  • Wrap up lighting
  • Audio
  • Audio / Lighting Quiz next week!
  • Demonstration video pitches next week in lab!
  • Talk about PSA Proposals, Demonstration Videos (due next week) and News stories (due the following week)

Readings: don't forget to do the cybercollege readings. Audio units: 37, 38, 39, 40 and 43.

Misc Announcements & Updates:

PSA Proposals - These are due by the start of lab this week. We'll take 15 minutes of lab time to share ideas.

Graphics Lab / Demonstration Video materials - Next week we'll have a lighting / audio quiz in lecture and start covering graphics. We'll meet here for lecture as usual- but the labs will be in a computer lab (TBA). In lab we'll cover Photoshop and you'll also pitch your Demonstration Videos. Please note that you'll have to submit a full pre-production packet for your Demonstration Video. This is worth 15 points and includes:

  • Program Proposal (includes title, objective, target audience, show description, production overview)
  • Treatment or Script (partial script format can be used which includes intro, talk points, segues and close)
  • Storyboarded key shots (Just include a few of the key shots.)
  • Floor plan & lighting plot

The week after next is our News/chromakey exercise. Will cover in lab next week. Students will have to write a 30-second news piece and prepare 2 graphics.

Wrapping Up Lighting------------------------

(Finish notes from last week.)

Studio lighting and set design tips:

Before designing and building sets think about what you want to see in the frame. Storyboard your key shots first. Then plan around them, creating a floor plan and lighting plot to match. If you are producing a talk show you might want consistent light and colors behind the MCUs of your guests. If you are producing a noir piece you might want room to see shadows.

Keep furniture (couches, tables, chairs, etc.) away from flats (at least 8 feet or so) or your lighting angles will be too high from having to shoot over the flats.

Keep key lights off of the set as much as possible. This way you can control them separately from the talent.  (You need proper light placement & set design to ensure you can do this.)

Scoops can work well to illuminate walls. Make sure they are hitting only the wall and not hitting the floor space. They can also be used to add a little touch of fill.

Use fresnels to create overlapping pools of light - Think about the areas where your actors need to be (in doorways, sitting at dining tables on couches, etc.). For most of these talent marks/areas, you'll need more than one key light. Use multple fresnels (NOT FLOODS) to make overlapping pools of light in these areas.

Realistic lighting: Try to have believable lighting. Visible lighting fixtures that are part of the set (a light next to a bed for example) can make a huge difference.

Aim to get around 65-70 IRE for Caucasian skin tones under daylight. (Evening/night scenes or darker-colored skin will be less.)

Try to get sets and flats about 20 IRE below the talent.

 

Audio ------------------------

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. 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.

In a live studio environment, background tracks must be thought of in advance. The production lab has a library of sound effects and a minidisc recorder. Think of your location and get fitting sound effects and music before you have to produce your project.

Audio perspective

Viewers expect sounds from far away to sound more distant and sounds nearby to sound more present. We've been listening to stereo and surround audio for years and are acustomed to taking cues of character positions or locations through the soundtrack. Imagine a long shot in a busy restaurant as our two stars enter and sit down at a table. Over the long shot we'd expect to hear quite a bit of ambient sounds. But then we cut into a closeer two shot, and the audio must sound more intimate. In addition, there's stereo imaging. The audio from the person on the left comes from the left side speaker. But then we cut in to the character with a full screen close up. The sound then comes from the middle.

This is why the boom mike is sometimes 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.

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 (CPS)

  • Hertz = Hz or 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

Impedance = resistance and is measured in ohms. It's important that the output and input impedances match in production gear.

  • High impedance = High Z, low impedance = Low Z.
  • Professional mics often have an impedance of around 150-200 ohms. Other devices (like electric guitars) can have impedances up in the thousands. You can use impedance matching transformers. (Plug an electric guitar into a microphone input)

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

Can be classified in many ways. Most useful are by:

  • Electrical characteristics (dynamic, condenser, ribbon, etc)
  • Pickup patterns (omni, cardioid, etc.)
  • Design (handheld, lavaliere, etc.)

Electrical Characteristics

  • Dynamic - durable. Works opposite of a speaker. A coil moves within a magnetic field
  • Condenser- need batteries or phantom power. 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.
  • Ribbon - delicate. A small ribbon moves inside a magnetic field

Pickup patterns:

  • Omni
  • Cardioid
  • Hyper-cardioid (Shotgun) Super Cardioid
  • Bi-directional a.k.a. Figure eight

Design:

  • Lavaliere (wireless are the norm) Great for TV production.
  • Hand held
  • Shotgun mic. (Typically used on a boom pole, also known as a fish pole. Great for film and storytelling projects.)
  • Headset
  • Contact microphone/transducer (pickups for instruments)
  • Boundary effect or PZM
  • Stands (floor & desk) obtrusive good for music; desk: obtrusive but have excellent audio quality (Leno, Letterman)
  • Parabolic

Proximity Effect - Sounds closer to the microphone have an exaggerated low frequency response. (Part of the reason radio announcers sound so "bassey" is because they are talking right into the mic.)

Pop-filter - Stops the letters B, P and T from "popping". (Typically a thin piece of fabric.)

Phase cancellation - Sound is a wave. When two mics pickup the same sound they will either magnify it if they are in phase, or reduce it if they are out of phase. Reducing the sound through multiple mics is known as phase cancellation. To avoid it assign one microphone s the primary pickup device for each source.

Phantom Power - A way to power condenser microphones over existing XLR cables. Typically 48 volts. Can be generated by mixers and cameras.

Wireless receivers - Diversity have two antennas. Non-diversity have only one.

Balanced vs. Unbalanced (XLR two conductor & ground). Balanced cables have three wires 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.

Different line levels (+4 dBm & –10 dBm). There are two different levels considered "line level". Professional equipment uses a slightly hotter signal of +4 dBm. 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.

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

 

Audio control booth/production room

Audio Control Booth is used during actual production

Audio Production room is used for post. This is where audio sweetening takes place. Sweetening is the process of adding track & SFX, tweaking eq etc.

Audio console:

Try to visualize the signal flow through the mixer. The audio signal enters at the top- where the preamp is. You can usually select line or mic. Mic levels are brought up to line levels. Really hot line levels are padded (resistance is added to reduce the gain) You don't want audio to clip or distort (make diagram of limited window & square waves)

Next you can have equalization & auxiliary sends (to effects, headphones, sub-mixes)

Lastly there is channel assign (depends on the number of outputs the console has) a pan pot, solo & mute buttons & a channel fader.

Output section contains master outputs for selected channels (eg 1-8 for an 8 channel board)

Boards are usually referred to as 16x2, 16x4. This is inputs verses the number of outputs.

In-line consoles don't use a separate output section. Each input has its own output.

Mix: combine signals

Phantom Power (48 volts) for condenser mics
Patchbay- connect the inputs to the outputs
Digital patchbay & routing (push a button instead of patching)
Calibration: make sure the record level matches the console output (0 vu) Basically make sure inputs match the outputs.

Outboard Gear / Useful audio plug-ins -

  • Equalizers
  • Reverb / SFX
  • Compressors & Limiters
  • Expanders

 

Up to Jim Krause's T356 homepage