Page 43 - Spring 2009

Instrumentation
Dick Stern
Applied Research Laboratory, The Pennsylvania State University PO Box 30, State College, Pennsylvania 16804
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AKG announced the most recent addition to their Perception Series of micro- phones with the introduction of the Perception 820 Tube Microphone. The micro- phone features a 20 dB attenuation pad and a low cut filter for an extensive range of microphone applications, including vocals, brass instruments, electric guitar amps and overhead miking. The ECC 83 dual-triode tube circuitry and the output transformer emphasize even-order harmonics for rich, smooth and three-dimen- sional sound. The remote control unit allows selection of 9 different pickup pat- terns from omni-directional to cardioid to figure eight. In addition, it also controls the switchable second-order bass-cut filter and the switchable attenuation pad. Moreover, a ground lift switch prevents unwanted hum if necessary. Designed and engineered in Vienna, Austria, the entire Perception line offers AKG’s signature sound quality captured in a rugged precision-tooled zinc/aluminum alloy body with a dent-resistant, stainless steel grille screen. The Perception 820 Tube comes complete with a robust metal carrying case, a spider-type shock mount, a micro- phone cable and the remote control unit. Contact: Chris Hertzog <chert- zog@griffinpr.com>
PCB Piezotronics, Inc. introduced their low cost, non-contact Model 130D20, ICP® electret microphone for frequency analysis and amplitude trending in the paper industry. When large capital equipment such as paper
rollers, break down, it costs companies large sums of money for repairs and lost revenue from downtime. By using frequency analysis or trending the ampli- tudes, maintenance technicians and plant engineers can predict when machines will need minor maintenance that will help avoid major repairs. Paper Roller machine manufacturers and end users often have concerns of material build-up, roller wear, and defects on the machine as paper passes through rollers over extended periods of time. By using PCB® electret microphone Model 130D20, and running the ICP® output signal through a programmable logic controller (PLC), the machine operator can set control limits in the PLC to alarm output any changes in sound waves. When the amplitude in decibels increases, or the frequency changes from normal set points, the alarm allows the machine operator time to investigate the source and plan for maintenance, which can end up saving tens of thousands of dollars in repairs and downtime. This short term preventative main- tenance can prevent catastrophic failures and also extend the lifespan of the machine. Contact: Jennifer Beal <prospects@pcb.com>
Editor’s Note—The items printed in “Instrumentation” are reported for informational purposes only and are not necessar- ily endorsements by the Editor, Acoustics Today, or the Acoustical Society of America.
42 Acoustics Today, April 2009