Sound Reinforcement Final Exam | updated 100% correct

Sound Reinforcement Final Exam | updated 100% correct What are the different types of distortion in a sound system? - 1. Overdriven sound 2. Harmonic distortions 3. Intermodulation distortion Personal PA - smallest PA system, 1-12 people, 10-20 ft Band PA - reinforces small to large venues, easily scalable, 10-2,000 people Touring PA - extreme, needs many trucks, set up, time, knowledge. Line array system. Point source - A single speaker or multiple speakers placed far apart Line source - uses physics to force sound at a greater distance by lining up multiple speakers in close proximity Three different uses of a sound system - 1. Public announcements 2. Direct Public address 3. Performance Distributed System - connects to multiple spaces/rooms. Advantages/disadvantages of a portable system - Advantages: specific to the band, doesn't have to be re-learned at each venue, can be adjusted for needs Disadvantages: more wear and tear, more travel costs Advantages/disadvantages of a permanent system - Advantages: specific to the acoustics of the venue, can be hidden by architecture, has optimal room-position Disadvantages: engineers have to learn it when they come to the venue, expanding it's capabilities would require further installations Power alley - The line between subwoofers where each woofer is in phase and noticeably louder. Boosts the low frequencies Phase time - In phase, out of time: still increases amplitude but contains a delay Out of phase, out of time: sounds cancel each other out RT60 - the amount of time it takes for reverb to decay 60 dB Absorption coefficient - The degree to which a material absorbs sound waves. Goes from 0-1 with 1 being 100% absorptive White noise - Equal energy per frequency Pink noise - Equal energy per octave How does a room's acoustics play into the way we set up our system? - Different room acoustics require different acoustic treatments and speaker placement in order to optimize phase-time relationships Inverse square law - you lose 6dB of audio for every doubling of distance from a speaker Why would we place our subs together and in mono at the center of the stage rather than in stereo? - To minimize phase cancellations and out-of-time sound waves coming from the subs. What equipment/information does a stage plot show? - Microphones, instruments, monitors, DI boxes, amps, channel inputs, phantom power, extra needs. What does a system diagram(line diagram) show? - Signal flow from the mic/line input to the monitor/speaker output. What information needs to be put onto an input list? - Source, microphone/DI, channel input, phantom power, and band Common stage terms - upstage (near back), centerstage, downstage(near front), stage right(audience left), stage left(audience right), wings, proscenium arch, apron, thrust, audience/house Different types of cable shielding - Foil, wire, and braided. Braided is the most protective, but the least flexible. Optical cable - Uses laser light to transmit signal