Gearslutz.com - View Single Post - Want to build a Binaural mic head... thoughts...

billgaylord · 30th April 2006

Some links that might be interesting to you:

You can get some amazing sound from these amazingly inexpensive microphone capsules (which are small enough to fit an ear canal opening), as explained on Siegfried Linkwitz's web site...

http://www.linkwitzlab.com/sys_test.htm

Stereo mic circuit using the Panasonic capsules...

http://www.linkwitzlab.com/images/graphics/microph2.gif

I have made my own binaural dummy head microphone out of wood and casts of my own ears (WARNING--DO NOT try to cast your own ear unless you really know how!! If you just pour casting material into your ear and let it set, you will destroy your eardrums trying to get it out!! Or wind up going to the hospital to get it removed!! To do it right you have to have a reliable way to provide air to the inside to relieve the vacuum. DO NOT TRY THIS AT HOME!!)

The size and shape of the head gives most of the effect, with pretty good horizontal spacial resolution and a sense of the sound being outside the head (when listening with headphones). A sphere about the width of a human head works amazingly well! If the outer ear parts are accurate anatomically speaking, they will add the virtical (azimuth) direction cues. Position in the "ear canals"--it turns out that putting them close to the openning tends to work best if you don't have a way to do "diffuse field equalization" of your dummy head's response.

The sound images above, to the sides, and behind will sound great! To the front it will still be amazing, but might sound a bit closer than you expect, and sounds to the front might be harder to locate if they aren't moving. It turns out sounds to the front are coupled to vision to a sizeable degree. People listening to a binaural recording, instantly could hear the frontal sound image much more distinctly once they got a look at a picture of the sound sources! Pretty amazing stuff. Most people can get the same affect if they imagine the sound sources.

I made the head with 1/2" birch veneer plywood cutouts layered and glued together. Each layer was cut on a bandsaw to a horizontal cross-section template. Pretty laborious, but it makes a pretty rugged dummy head and it's acoustic properties seem to be decent (no annoying stray resonances). The back can be removed for access to the circuit board and microphone capsules and I attached a tripod mount to the bottom.

You can hear some recordings made with this microphone on my experiments web site (binaural link at the bottom):

http://wjgaylord.brinkster.net/

Bill Gaylord

30th April 2006	#4
billgaylord Gear interested Joined: Apr 2006 Posts: 1	Some links that might be interesting to you: You can get some amazing sound from these amazingly inexpensive microphone capsules (which are small enough to fit an ear canal opening), as explained on Siegfried Linkwitz's web site... http://www.linkwitzlab.com/sys_test.htm Stereo mic circuit using the Panasonic capsules... http://www.linkwitzlab.com/images/graphics/microph2.gif I have made my own binaural dummy head microphone out of wood and casts of my own ears (WARNING--DO NOT try to cast your own ear unless you really know how!! If you just pour casting material into your ear and let it set, you will destroy your eardrums trying to get it out!! Or wind up going to the hospital to get it removed!! To do it right you have to have a reliable way to provide air to the inside to relieve the vacuum. DO NOT TRY THIS AT HOME!!) The size and shape of the head gives most of the effect, with pretty good horizontal spacial resolution and a sense of the sound being outside the head (when listening with headphones). A sphere about the width of a human head works amazingly well! If the outer ear parts are accurate anatomically speaking, they will add the virtical (azimuth) direction cues. Position in the "ear canals"--it turns out that putting them close to the openning tends to work best if you don't have a way to do "diffuse field equalization" of your dummy head's response. The sound images above, to the sides, and behind will sound great! To the front it will still be amazing, but might sound a bit closer than you expect, and sounds to the front might be harder to locate if they aren't moving. It turns out sounds to the front are coupled to vision to a sizeable degree. People listening to a binaural recording, instantly could hear the frontal sound image much more distinctly once they got a look at a picture of the sound sources! Pretty amazing stuff. Most people can get the same affect if they imagine the sound sources. I made the head with 1/2" birch veneer plywood cutouts layered and glued together. Each layer was cut on a bandsaw to a horizontal cross-section template. Pretty laborious, but it makes a pretty rugged dummy head and it's acoustic properties seem to be decent (no annoying stray resonances). The back can be removed for access to the circuit board and microphone capsules and I attached a tripod mount to the bottom. You can hear some recordings made with this microphone on my experiments web site (binaural link at the bottom): http://wjgaylord.brinkster.net/ Bill Gaylord