AET 2560 - Sound Reinforcement Final Exam 2023 Guide with complete solution

AET 2560 - Sound Reinforcement Final Exam 2023 Guide with complete solution illegal frequency bands 100 - 799 mHz squelch a circuit for preventing a radio receiver from producing audio-frequency output in the absence of a signal having predetermined characteristics diversity receiving two antennas switching systems to pick up strongest signal from antenna difference between limiting and compressing compressor: a signal processor that for a given input amplitude range produces a smaller output range limiter: a signal processor in which some characteristic of the output is automatically prevented from exceeding a predetermined value side-chain input on a compressor input to the gain reduction stage of circuit allows external audio source to control gain reduction gate attenuates signals that register below the threshold; the gate opens when signals pass the threshold downward expander when the signal level drops below the threshold, the signal gain is decreased notch filter a band-stop filter with a narrow stop band (high Q factor) advantage of using stereo input channel over a reverb return ... parametric EQ provides both sweepable center frequencies and adjustable Q, as well as boost / cut controls semi-parametric EQ provides control of the amplitude and frequency, but uses a pre-set bandwidth of the center frequency non-parametric EQ ... graphic EQ multi-frequency, band reject filter, or a band-pass / reject filter LPF low-pass filter; passes low-frequency signals and attenuates signals with frequencies higher than the cutoff frequency BPF band-pass filter; passes frequencies within a certain range and attenuates frequencies outside that range HPF high-pass filter; passes high-frequency signals but attenuates signals with frequencies lower than the cutoff frequency threshold certain dB point at which a compressor reduces the level of an audio signal if its amplitude exceeds that point ratio amount of gain reduction 4:1 means that if input level is 4 dB over the threshold, the output signal level will be 1 dB over the threshold; the gain (level) has been reduced by 3 dB attack period when the compressor is decreasing gain to reach the level that is determined by the ratio release period when the compressor is increasing gain to the level determined by the ratio, or, to zero dB, once the level has fallen below the threshold make-up gain the gain for after a signal undergoes the gain reduction process of compression personal PA ... fixed installation permanent, consistent, ready inflexible, costly distributed system multiple sections of speakers, point source headroom the amount by which the signal-handling capabilities of an audio system exceed a designated level distortion any kind of deformation of an output waveform compared to its input usually clipping, harmonic distortion, or intermodulation distortion (mixing phenomena) caused by non-linear behavior of electronic components and power supply limitations crest factor measure of a waveform, such as alternating current or sound, showing the ratio of peak values to the average value gain before feedback a measure of how much a microphone can be amplified in a sound reinforcement system before causing audio feedback NL2, NL4, NL8 speakon connectors NL2: 1+, 1- NL4: 1+, 1-, 2+, 2- NL8: 1+, 1-, 2+, 2-, 3+, 3-, 4+, 4- balanced cable contains two identical wires, which are twisted together and then wrapped with a third conductor (foil or braid) that acts as a shield drive rack graphic EQ, crossover, amplifiers, etc. advantages / disadvantages of active and passive crossovers active: flexible, adjustable filters / amplification; filtering occurs before amplification and needs an external power source passive: power source is in same system; predetermined crossover slope and points 2-way, 3-way, 4-way system 2-way: consists of a low-pass and a high-pass filter 3-way: constructed as a combination of low-pass, band-pass and high-pass filters (LPF, BPF and HPF respectively) 4-way: constructed as a combination of low-pass, band-pass and high-pass filters (LPF, BPF and HPF respectively) how do you set up auxiliary driven subs, what is the advantage it gives ... how do you calculate a speaker's delay setting, what is the rule of thumb [NOT ON TEST] what is the purpose of limiting the drive line ... amp class A refers to an output stage with bias current greater than the maximum output current, so that all output transistors are always conducting current biggest advantage is that it is most linear, ie: has the lowest distortion amp class B have output stages which have zero idle bias current have a significant advantage over Class A in efficiency because they use almost no electricity with small signals amp class AB almost the same as Class B amplifiers in that they have two driven transistors; however, Class AB amplifiers differ from Class B amplifiers in that they have a small idle current flowing from positive supply to negative supply even when there is no input signal called Class AB rather than Class A because with large signals, they behave like Class B amplifiers, but with small signals, they behave like Class A amplifiers. Most amplifiers on the market are Class AB amp class C