Re: "El Cheapo" dummy heads? (Henrik =?iso-8859-1?Q?M=F8ller?= )

Subject: Re: "El Cheapo" dummy heads?
From:    Henrik =?iso-8859-1?Q?M=F8ller?=  <hm(at)KOM.AUC.DK>
Date:    Mon, 9 Jul 2001 15:31:12 +0200

This is a multi-part message in MIME format. --------------A889E0F3A971D29CC1729C18 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit I can only support Peter's (and other's) ideas of "home made" dummy heads. It may give you a lot of fun. The first step of getting something better for headphone reproduction than traditional recordings is very easy. Spaced microphones, possibly with a sphere between - as proposed - is excellent. (There are also commercial "sphere" microphones, as far as I remember from Schoeps). If you make your own head, you should use pressure type microphones, and they can be obtained from a dollar and up. The second step is to use a real head. In fact you get the best dummy head recordings FOR YOU, when you record in your own ears. In order to get the perfect sound, make sure to equalize the headphone and the whole system; it should have a flat frequency response when measured on your head and with the microphone you record with, still in the same position. I can especially recommend that you insert the microphones in earplugs. (Then you won't hear the sound during recording, but you can enjoy it many times afterwards). You can read about details in our paper: - Henrik Møller, Michael Friis Sørensen, Clemen Boje Jensen, Dorte Hammershøi: "Binaural technique: Do we need individual recordings ?", Journal of the Audio Engineering Society, Vol. 44, No. 6, June 1996, pp. 451-469. Third step, going to a dummy head is actually one step back for the reproduction of space as compared to individual recordings, but for most applications individual recordings are not really feasible. Dummy heads aim at copying an average human acoustically. Unfortunately, that is not an easy task, since we are so different, especially when it comes to the pinna. We have tested dummy heads in several investigations, and a summary is given in the May issue of the Journal of Audio Engineering Society, which just dropped into my mailbox a few days ago. (Is it only in Denmark that journals are always delayed?): - Pauli Minnaar, Søren Krarup Olesen, Flemming Christensen, Henrik Møller: "Localization with binaural recordings from artificial and human heads", Journal of Audio Engineering Society, Vol. 49, No. 3, May 2001, pp. 323-336. Talking about the price of dummy heads, there are reasons why they are expensive. They come with high quality microphones with low noise, usually also preamplifiers, maybe phantom power, and possibly some more electronics. The channels are matched, and sensitivity and frequency response are stable. And the head itself must be produced, often in low numbers. Some heads have mechanically complicated ear simulators in order to comply with international standards for various purposes. (Many of the heads are actually not really made for recording). Henrik Møller --------------A889E0F3A971D29CC1729C18 Content-Type: text/x-vcard; charset=us-ascii; name="hm.vcf" Content-Transfer-Encoding: 7bit Content-Description: Card for Henrik Møller Content-Disposition: attachment; filename="hm.vcf" begin:vcard n:Møller;Henrik tel;fax:+45 9815 2144 tel;work:+45 9635 8710 x-mozilla-html:TRUE url: org:Aalborg University;Department of Acoustics adr:;;Fredrik Bajers Vej 7 B4;Aalborg Ø;;DK-9220;Denmark version:2.1 email;internet:hm(at) title:Professor, Head of Department fn:Henrik Møller end:vcard --------------A889E0F3A971D29CC1729C18-- ------------------------------

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