HI, the front-back reversals problem isn't peculiar to ambisonics - it can sometimes happen in real life (most often, though not always, in a symmetrical space) and is well known in the laboratory. It's really a subset of the 'cones of confusion' problem, which Batteau proposed that Pinnae effects help with, and Wallach proposed head movements help with - and I'd say you get best results with both. Since ambisonics, especially in lower orders, actually homogenises potential pinnae cues (eg using multiple sources to produce a simulation of a plane wave from a single source), then 'search behaviour' - small head movements to produce different sets of pinnae cues- works less well than for real environments; movements have to be grosser, and for longer. Higher orders help, some kind of processing for high frequencies (Harpex, for instance) might help. I've even cheated with this and used a precedent (about 7ms), bandwidth limited, amplitude limited, version of a target source simply routed into a single speaker - sort of an infinite order applied to transients. This last removes some of the actual reversals that you get ion a large array with off-centre listeners
cheers Dr. Peter Lennox School of Technology, Faculty of Arts, Design and Technology University of Derby, UK e: p.len...@derby.ac.uk t: 01332 593155 -----Original Message----- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of Chenrilin Sent: 09 January 2013 03:29 To: sursound@music.vt.edu Cc: Zhangdeming Subject: Re: [Sursound] Array for sound field recording and extend the sound image <Without more details, it hard to speculate about problems, but I'll note <that subtracting the outputs of two omnis to get a fig-8 response will <result in a frequency response that rises 6dB/octave with a 90 degree phase <shift relative to the sum. Unless that is corrected, these signals are not <suitable for B-format. I have checked my encoder, and definitely right as you said. I have just compensated for the magnitude and lost the phase modification. After modified, the location of audio is right and the sound image have been extended and much natural. But if the location of the sound is on the front of array, the listener cannot perceive clearly ・ whether the audio is in the front or on the back. I think it needs more processing, e.g. add ・ head tracking. If I have I have good result, I will share it with all. But it need more time since ・ I am not familiar with it：） ・ ・ Thanx very much for help from all of you. ________________________________ 华为技术有限公司 Huawei Technologies Co., Ltd. [Company_logo] Phone: Fax: Mobile: Email: 地址：深圳市龙岗区坂田华为基地 邮编：518129 Huawei Technologies Co., Ltd. Bantian, Longgang District,Shenzhen 518129, P.R.China http://www.huawei.com ________________________________ 本邮件及其附件含有华为公司的保密信息，仅限于发送给上面地址中列出的个人或群组。禁 止任何其他人以任何形式使用（包括但不限于全部或部分地泄露、复制、或散发）本邮件中 的信息。如果您错收了本邮件，请您立即电话或邮件通知发件人并删除本邮件！ This e-mail and its attachments contain confidential information from HUAWEI, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it! -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130109/4a9de64c/attachment.html> -------------- next part -------------- A non-text attachment was scrubbed... Name: image001.jpg Type: image/jpeg Size: 6737 bytes Desc: image001.jpg URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20130109/4a9de64c/attachment.jpg> _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _____________________________________________________________________ The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this email was sent to you in error, please notify the sender and delete this email. Please direct any concerns to info...@derby.ac.uk. _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
