Product Noise
We work on acoustic issues for products ranging from reducing the sensitivity of scanning electron microscopes, hardware for use on submarines and consumer products (such as high-end video monitors), to reducing the noise emissions of medical devices with critical cooling requirements. We troubleshoot acoustic noise problems and design solutions. Product noise can radiate directly from fans or turbulent air flow, but is often also radiated by vibrating surfaces excited by vibration sources, such as fans, motors, compressors, actuators, gears, etc. The structural dynamics from the mounting of the source to the radiating surface can be very important. We look at the larger picture where we consider the following:
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Source Identification
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Transmission path
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Structural Dynamics
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Frequency Content
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Acoustics of Enclosed Spaces
We often begin a project by characterizing the sound levels in a controlled and repeatable environment. We may then use Acoustic Intensity Testing to test which surfaces are radiating the most sound, and in which frequency bands.
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An acoustic consultant must also be a vibration consultant as both fields of study are intimately related. We are fluent in both languages and have had undergraduate and graduate courses on these subjects. The theoretical background is important in modeling and understanding the dependencies in each field, how and why they are coupled phenomena. However, solving real world problems to characterize and test the mechanical/acoustic issue and apply pragmatic solutions quickly and effectively does require years of hands-on experience.
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We work on acoustic issues for products ranging from reducing the sensitivity of scanning electron microscopes, military hardware for use on submarines, consumer products such as high-end video monitors, to reducing the noise emissions of medical devices with critical cooling requirements. We troubleshoot acoustic noise problems and design solutions.
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Dynamic Testing, Modal Analysis Testing and Operating Deflection Shape Testing are also often very helpful in understanding exactly how and why the product is radiating sound.
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In designing solutions, we may consider Vibration Isolation of sources, Damping Treatment of resonant structures, as well as acoustics shielding, ducting, and acoustic absorption.
Often characterization of the sound in both the time and frequency domain will be helpful in identifying the source and in choosing how best to characterize the sound for comparison as improvements are made to the system.
The mechanical coupling of vibration sources to surfaces that will turn the vibration into sound is key to quieting a product as a first step. We are often presented with the problem of decoupling a source while staying within the mechanical constrains of the existing product. Because we understand vibration, dynamics, and acoustics, we will often arrive at an optimized solution more rapidly. We do prototyping of solutions in our lab and on-site, and then test and characterize those solution options so that the engineering team can compare improvements using quantified and comparable metrics.
Response Dynamics has performed acoustic noise sensitivity tests on many high resolution tools including scanning electron microscopes, atomic force microscopes, profilometers, precision timing electronics, etc. We have developed techniques that provide repeatable sensitivity data and then translate our test data to a meaningful and effective acoustic noise specification that can be used for site evaluation and customer acceptance. Our sensitivity testing often also involves vibration and magnetic field tests. We sometimes perform these tests to base line a tools acoustic noise, vibration, or magnetic field sensitivity before making improvements to the tool to improve its performance and make it less sensitive to disturbance. (see Sensitivity Testing for more details)
