Survey of Sound class 5

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In Class

  • Take Quiz
  • Listen to Project 2
  • Microphones

Signal flow

Block Diagrams (how audio moves though a system)

make examples of block diagram
make diagram for room 605
make diagram for theater

Audio Levels

Good Level Audio Levels

  • Microphone level - The level (or voltage) of signal generated by a microphone. Typically around 2 millivolts. Compare this with the two normal line levels
  • Phono Level - little larger than mic level also has equalization based on standardized RIAA curve. use phono input a line
  • Line Level - . There is an international standard for the level of inputs; it is around -10dBV(.316V) for semi-pro equipment, and about +4dBu(1.228V) for "pro" equipment. Line level outputs can come from tape decks, CD players, tuners, DAT decks, effects, etc. (1.228V:+4dBu and .316V:-10dBV)
  • Speaker level - higher voltages for speakers

Audio Level Links

Audio connectors

  • 1/8" (3.5mm) Connectors Jack Plug Connectors Tip ring sleeve Connectors Eighth.jpg mono Connectors Eighth mono.jpg stereo Connectors Eighth st.jpg
  • 1/4"(6.35mm) Connectors Connectors QuarterBend.jpg Connectors Quarter.jpg
  • Banana Plugs Connectors Bannana.jpg
  • Binding Posts Bayonet Neill-Concelman/British Naval Connector type of signal varies or BNC Connectors Bnc.jpg
  • RCA-Type video left audio right audio Connectors Rca y.jpg Connectors Rca bl.jpg Connectors Rca w.jpg
  • XLR Microphone XLR Connectors Xlr.gif
  • TOSLink TOSLINK.jpg

Bluffers guide to WIRES AND CONNECTORS


Transducer = a device that converts one type of energy to another. A microphone converts acoustic energy to electrical energy. A speaker converts electrical energy to acoustical energy. They are both transducers.



good reading Audio Technica Guide to Microphones

Types of microphones

  1. Dynamic
  2. Condenser
  3. Ribbon
  4. piezo electric (contact Mic)

other (Stereo, binaural, PZM- pressure zone microphone

Ribbon Mic

The first type of mic was a Ribbn Microphone. Basically a light wieght ribbon that conducts electricity the is suspened in between two magnets. Older ribbon mics usally have a reduced frequency response.

Dynamic Mics

A light weight diaphragm is connected to a coil that is suspended between a magnet.


Condenser Microphone

A very light weight diaphragm is suspended in front of an electrically charged back plate. The two plates basically act as an open air capacitor. As the air pressure changed the distance between the plated the capacitance between the plates also changes.

Condenser microphones need Phantom Power to work.

399px-Microphone U87.jpg

Our stereo mic: Audio Technica AT825 [1]

Microphone Comparison

Parameter Dynamic Condenser Ribbon
Frequency Response Good Best Worst
Dynamic Range Good Good Worst
Durability Best Good Worst

Proximity Effect

The frequency response of a directional microphone changes as it it brought close to a source. The bass response increases.

Polar Patterns

  • Omni-directional - all directions
  • Bi-directional (figure 8)- front and back rejects on the side
Bi-directional (figure 8)
  • Uni-directional - one direction
  • Cardioid - one direction with lobe
  • Hypercardiod - really one direction with lobe
hyper cardioid Microphone Directionality Some pictures Some more Pictures

Stereo Mic Techniques

Spaced Omni's - two spaces Omni mics

XY - Coincident cardioids at 90 degrees

ORTF (Office de Radiodiffusion -- Television Francaise)110 degrees 17cm apart - Near Coincident Pair Microphones Part 1

Dat Heads mic-FAQ.txt


finish sound Enviroment


Sound for Interaction Voice Recording