Category: Reading

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Hello Raspberry Boom!

Last week I finally received my Raspberry Boom I backed at kickstarter a few months ago. The Raspberry Boom is an infrasound measurement device for measuring inaudible low-frequencies in atmospheric and man-made events such as rocket launches, explosions, volcanic eruptions, storms, tornadoes, lightning, etc. The journal Physics Today just had an article on that topic.

I hooked up the boom circuit to a Raspberry Pi Zero W which is doing data collection and transmission to the global citizen science network for further analysis and data fusion, such as for earthquake detections. You can check out my station’s real-time data here.

At the moment the boom sits inside its housing on the window of my home office. I still need to find a permanent place to minimize the likelihood of it falling down and the influence of low-frequency wind turbulences.

 

 

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New book on sound-field reprodution

Between The Ahnert and The Blauert, there is a new book in my library: The Ahrens:


From the description:

This book treats the topic of sound field synthesis with a focus on serving human listeners though the approach can be also exploited in other areas such as underwater acoustics or ultrasonics. The author derives a fundamental formulation based on standard integral equations and the single-layer potential approach is identified as a useful tool in order to derive a general solution. He also proposes extensions to the single-layer potential approach which allow for a derivation of solutions for non-enclosing distributions of secondary sources such as circular, planar, and linear ones. Based on above described formulation it is shown that the two established analytic approaches of Wave Field Synthesis and Near-field Compensated Higher Order Ambisonics constitute specific solutions to the general problem which are covered by the single-layer potential solution and its extensions. The consequences spatial discretization are analyzed in detail for all elementary geometries of secondary source distributions and applications such as the synthesis of the sound field of moving virtual sound sources, focused virtual sound sources, and virtual sound sources with complex radiation properties are discussed.

Another gem is the accompanied website, where Jens provides the Matlab source code for all Matlab figures used in this book – bravo Jens.