Audio Engineering Society Convention Paper 8125 Presented at the 128th Convention 2010 May 22–25 London, UK The papers at this Convention have been selected on the basis of a submitted abstract and extended précis that have been peer reviewed by at least two qualified anonymous reviewers. This convention paper has been reproduced from the author's advance manuscript, without editing, corrections, or consideration by the Review Board. The AES takes no responsibility for the contents. Additional papers may be obtained by sending request and remittance to Audio Engineering Society, 60 East 42 nd Street, New York, New York 10165-2520, USA; also see www.aes.org. All rights reserved. Reproduction of this paper, or any portion thereof, is not permitted without direct permission from the Journal of the Audio Engineering Society. Improvements on a Low-Cost Experimental Tetrahedral Ambisonic Microphone Dan T. Hemingson 1 and Mark J. Sarisky 2 Butler School of Music, The University of Texas at Austin, Texas 78712, USA 1 dhemingson@mail.utexas.edu 2 sarisky@mail.utexas.edu (Section 8. Reference URLs updated November 24, 2015) ABSTRACT An earlier paper [1] made a comparison of two low-cost tetrahedral ambisonic microphones, an experimental microphone and a Core Sound TetraMic, using a Soundfield MKV or SPS422B as a standard for comparison. This paper examines improvements to the experimental device, including that suggested in the “future work” section of the original paper. Modifications to the capsules and a redesign of the electronics package made significant improvements in the experimental microphone. Recordings were made in natural environments and of live performances, some simultaneously with the Soundfield standard. Description of the recording process is included. Of interest is the use of the low-cost “do-it-yourself” surround microphone for student and experimental education. 1. INTRODUCTION Further development of the experimental microphone introduced in a previous paper [1] resolves many of the technical issues associated with using an experimental ambisonic microphone. The recent introduction of relatively low-cost commercial ambisonic microphones has created a greater interest in surround recording. A proven “do-it-yourself” experimental tetrahedral ambisonic microphone would make surround recording a reality for many students, educational institutions, and experimenters. The “new and improved” microphone, dubbed Experimental 2 or Exp2, was built on the knowledge and experience gained from the original design, including the feedback from the musicians whose performances were recorded and the results from the listener survey of those recordings made with the original device, now called Experimental 1 or Exp1.