The Future of Sound Reinforcement(?) Prof. David G. Meyer School of Electrical & Computer Engineering

Outline Sound Reinforcement System Design Goals Factors Which Complicate Sound Reinforcement System Design Proven Ways to Design Sound Reinforcement Systems New Developments Summary / Conclusions

Sound Reinforcement System Design Goals evenness of coverage intelligibility (articulation loss of consonants) ratio of direct sound field to reverberant sound field gain before feedback SPL at furthest listening position frequency range/response smoothness of frequency response curve locality of reference headroom

Factors Which Complicate Sound System Design reverberation / echo early / late arrivals room surfaces (absorption) room geometry seating characteristics variable fill empty room  full room

Proven Ways to Design Sound Reinforcement Systems central cluster  excellent coverage  high intelligibility  high gain before feedback  smooth frequency response  good locality of reference –cluster needs to be large for long, narrow room –potential for interference in driver overlap regions –hard to hide architecturally –“ugly hanging mess”

Central Vertical Line Array

Proven Ways to Design Sound Reinforcement Systems split source / “point and shoot”  best if multi-channel  high intelligibility  potential solution for challenging room geometries  generally more aesthetically pleasing (but not always) –potential for creating large interference zone –potential for loss of locality of reference –potential for limited frequency range over which directional control is possible

Split Source / “Point and Shoot”

Proven Ways to Design Sound Reinforcement Systems distributed / delayed  good solution for large, absorptive rooms with low ceilings  potential solution for challenging room geometries  potential solution for reinforcing “distant” zones –requires digital delays / multiple amplifiers (expensive) –potential for loss of locality of reference –generally not well suited for rooms with high ceilings (or that are highly reverberant)

Distributed / Delayed

New Developments Before its time in ’89… Renkus-Heinz Iconyx Yamaha YSP-1 Pioneer PDSP-1 Sounds Good Patent

Back to the problematic long, narrow room…

15+ years later…

ECE 477 Digital Systems Senior Design Project  Spring 2007 SOUNDS GOOD / DS 3 Digital Steerable Sound System Digijock(ette)-Strength Digital System Design TM PROJECT DESCRIPTION: -Digitally Steerable Sound System, allows for non-ideal placement of speakers -Six Preset Equalization Modes -Wireless Control Interface Joe Land, Ben Fogle, James O’Carroll, Elizabeth Strehlow ILLUSTRATION OF CONCEPT: USER MENUS CONCEPT: PCB LAYOUT: LOUDSPEAKER UNIT: FRONT BACK Top Copper Bottom Copper USER INTERFACE UNIT: SIGNAL PATH:

Back to the future?

Summary / Conclusions there is no universal, “one size fits all” solution to sound reinforcement system design knowledge of physics (sound propagation, room acoustics), electrical engineering (amplifier technology, wireless microphones), and computer engineering (digital signal processing, network technology, system monitoring, automation/control) are all helpful in formulating an optimal solution there are some new, exciting possibilities!