Exam 2 Study Guide - Purdue Engineering

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ECE 40020 Sound Reinforcement System Design © 2017 by D. G. Meyer Exam 2 Study Guide Thursday, March 30, 9:00-10:15 am Material covered: Chapters 4-9 plus supplemental reading Chapter 4 – Evaluation  Features of natural emission/transmission/reception  Features of amplified emission/transmission/reception  Subjective room parameters (quiz each other over these) o intimacy o liveness o warmth o definition/clarity o brilliance o diffusion o balance o blend o ensemble o immediacy of response o texture o dynamic range o tonal quality o uniformity Chapter 5 – Prediction  Limitations of 2D to 3D transformations o mismatch between speaker propagation plane and prediction plane o forms of speaker-prediction divergence  Loudspeaker aiming angles/degrees of freedom o elevation (latitude) o train (longitude, azimuth) o rotation (skew)  Limitations of prediction software  Loudspeaker data formats o “ideal” resolution needed o “spatial aliasing” that can occur if radiation pattern is under-sampled Chapter 6 – Variation  Minimum variance principles o level o spectral o ripple  Extending minimum level variance (multiple speakers) o forward o radial o lateral 1 ECE 40020        Sound Reinforcement System Design © 2017 by D. G. Meyer Spectral variance o spatial over spectrum o spectral over space o relation to speaker order o progressions Spectral tilt o transmission-related effects o summation-related effects o progressions Pink shift o perception of distance to sound source o analogous to pink (spectrally shaped) noise Ripple variance o source displacement o pattern overlap o progressions Forward aspect ratio (FAR) Proximity ratio o measure of asymmetry of coverage shape o indicates when “fill” subsystems are needed Minimum variance vs. maximum acceptable variance methods o seeks to find where -6 dB points fall on listening area edge o maximum: uses end-point of width o minimum: uses mid-point of width Chapter 7 – Combination  Role of overlap  Coupled line source arrays  Coupled point source arrays  Asymmetric coupled point source arrays o splay o level  Uncoupled line source arrays  Uncoupled point destination arrays  Beamwidth relation to aspect ratio shapes  Possible outcomes of beam combinations o coupling o isolation o combing  Beamwidth shapes o no plateau o with plateau o conversion to FAR shapes  Array building – plausible beamwidth shape building blocks o 2nd order (“constant directivity”) o 3rd order 2 ECE 40020   Sound Reinforcement System Design © 2017 by D. G. Meyer Effects o speaker order o speaker quantity o level tapering o splay angle o lateral spacing Asymmetric arrays o geometric center o acoustic center o power capability Chapter 8 – Cancellation (LF Steering)  Cancellation effects  Quantity and spacing effects  Basis of delay steering  Subwoofer arrays o line arrays o point source arrays o compact cardioids arrays o end-fire arrays  Field applications Chapter 9 – Specification  Mono mains o single/multiple o array type  Stereo (limitations)  Surround  Subsystem types o sidefill o infill o downfill o frontfill o delays  Balcony (use of return ratio)  Symmetric coupled point source design  Asymmetric coupled point source design (compensated unity splay angle)  Asymmetric-composite coupled point source design  Symmetric uncoupled line source array design  Symmetric uncoupled point source array design  Diagonal plane compensation Supplemental Reading (hard copy supplied with exam): 1. Bose Panaray MA12 Modular Array: Technical Foundation & Discussion 2. DSP Beam Steering with Modern Line Arrays (Meyer Sound 2002) 3. Meyer Sound CAL Array 4. Renkus-Heinz Iconyx Array 3