This is a presentation for the paper titled "3D Microphone Array Comparison: Objective Measurements", published in the Journal of the Audio Engineering Society in Nov 2021. H. Lee and D. Johnson, “3D Microphone Array Comparison: Objective Measurements” J. Audio Eng. Soc., vol. 69, no. 11, pp. 871–887, (2021 November). DOI: https://doi.org/10.17743/jaes.2021.0038 The paper analyses different 3D microphone arrays using objective parameters and provides theoretical insights into perceptual differences among the arrays, which will be formally investigated in future subjective listening tests. The impulse responses and recordings made using the microphone arrays are available from the 3D-MARCO database: https://doi.org/10.5281/zenodo.3477602 A detailed review of existing 3D microphone arrays for immersive recording is available from H. Lee, “Multichannel 3D Microphone Arrays: A Review,” J. Audio Eng. Soc., vol. 69, no. 1/2, pp. 5–26 (2021 Jan.). https://doi.org/10.17743/jaes.2020.0069.