Audio Signal sound waves of compressed air molecules diaphragm permanent magnet moving core waves of electrical energy coil Microphone coil and core magnet electrical signal diaphragm sound waves Speaker Microphones Mics are classified by either: their generating element (transducer) dynamic condenser (electret) ribbon (velocity) their pickup pattern omnidirectional cardioid or unidirectional Generating Elements - Transducers output voltage diaphragm polymer film diaphragm impedance converter spacer output voltage magnet voice coil permanently charged perforated back plate electret coating magnetic structure Dynamic Condenser Microphone Element Microphone Element Performance Characteristics of Mic Transducers Dynamic mics durable, have good sound quality Condenser mics excellent sound (good frequency response), require a power source, are somewhat fragile Ribbon mics produce warm sound (excellent frequency response), are extremely fragile Dynamic and Condenser Mic Pros and Cons Dynamic Mic Advantages Condenser Mic Advantages Rugged More Sensitive Lower Cost Better Audio Quality No Power Required Can Be Extremely Small Dynamic Mic Disadvantages Condenser Mic Disadvantages Lower Sensitivity and Power Higher self-noise Output More Fragile Larger and Heavier More Expensive Slower Response Time Prone to Weather Problems and Not the Best Choice for RF Interference Maximum Audio Quality Omnidirectional Pickup Pattern Omnidirectional Pickup Pattern Cardioid Pickup Pattern Cardioid Pickup Pattern Hypercardioid Pickup Pattern Connectors XLR connectors phono plug RCA phone plug mini plug Audio Mixer Select and amplify the incoming sound signals. Control the volume of the various inputs. Mix or combine and balance two or more incoming sound signals. Mixer Inputs Each input module requires that you select either the mic or line input. Mixer Output/VU Meter The mixed and quality- processed signal is then routed to the output, sometimes called line-out. Volume Unit (VU) Meters Analog VU Meters VU meters measure the volume units, the relative loudness of amplified Digital VU Meters sound. Calibration An audio system is calibrated when all VU meters respond in the same way to a specific audio signal—the control tone. Here the line-out of the audio mixer is calibrated with the input (recording level) of the VTR. Both VU meters show the same value. Mixing Control—Analog Audio Create proper balance of sound. Keep VU meter(s) in range between 60- 100% (-5 to 0). VU above 100% 100% distorts VU below 60% 60% sounds weak and may introduce noise into the audio signal. “Riding the gain” means adjusting the input faders to maintain optimal level and balance. Digital Audio Display Stereo meters Calibration—Digital Audio Digital sound is especially susceptible to overmodulation. Stereo You should meters therefore set the Display audio levels somewhat lower Contrast than for analog control sound. To calibrate our digital console feed a -12db tone. Left Tab Right Tab That is the optimal Scroll button [F1]–[F4] buttons Scroll button level for Final Cut Pro. Mixing Control—Digital Audio Digital sound is especially susceptible to overmodulation. You should therefore set Stereo the audio levels meters Display somewhat lower than for analog sound. Contrast control Set the input faders at a maximum of -15 to -12db rather than 0db. “Riding the gain” Left Tab Right Tab means adjusting the Scroll button [F1]–[F4] buttons Scroll button input faders to maintain optimal level and balance.
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