Building a Binaural Microphone (Part 1)

Binaural audio recording has always fascinated me since I first heard it and learned about it college oh so many years ago. In 1992, a binaural microphone setup cost $10,000 or move. Bad news, in 2016, a Neumann KU 100 Dummy Head Microphone costs $8,000, but there are several cheaper alternatives.

Several months ago, I was trying to figure out how to record sessions of Munchkin Land, the gaming podcast I produce for MajorSpoilers.com, when A) I only had four headset microphones for a five person game, and B) I wanted to try something different that wasn’t what people normally expect from our shows.  This lead me to a quick search to see if binaural microphones had come down in price, and though the Neumann microphone was still way out of reach, I did discover technology had advanced to the point where a very different type of microphone had been developed.

A traditional binaural microphone takes a stereo microphone, and embeds each mic in the ears of a foam head that then mimics the placement and shape of our own ears. But what if you could remove the foam head and place the mics in your own ears? That is the premise The Sound Professionals went with when they developed an in-ear binaural microphone.

The tiny microphones fit into your ear like a pair of normal earbuds, but instead of playing sound, the mic sends audio from your ears to a portable recorder. The mic needs to be powered by the recorder, but the system works for the low, low price of $89.

Yes, I was a bit skeptical too. How good could an $89 microphone be? Turns out, the binaural in-ear microphone works pretty darn well.

Put on a pair of headphones, turn up the volume and take a listen to this test I did on a stormy night on September 17, 2016.

I found it takes about five minutes to really let the audio transport you to the environment, but when it does, it is pretty amazing.

I then jumped on the idea of creating a series of Naturescapes to share with people, and when the next storm arrived, I was ready to sit outside (under the porch) to record the event. Unfortunately, the wind was blowing really hard, and I got soaked. Also troubling were the lighting strikes nearby. The last thing I want is to be struck by lightning while trying to record a lightning storm for strangers on the Internet. Finally, as I was being eaten alive by mosquitos, every little scratch and clearing of my throat was picked up by the mic (I may have also dozed off for a few minutes along with some “heavy breathing”). While I love this cheap alternative, the human factor ultimately ruined the recording.

This experience had me thinking about the Neumann microphone once again. What would happen if i bought a foam head and put the $89.00 binaural microphone in it? Our local Hobby Lobby sells foam heads for $7.00/each. The big downside is the dummy head doesn’t have realistic ears. On the plus side, I do have a 3D printer.

Because the human ear is flexible, and the “softness” of our ears affects the reflection and absorption of sound, I first wanted to print the ears using a flexible filament I have had in my stockpile for a couple of years. I believe I was totally on track with this, but unfortunately, my 3D printer had other ideas.

If you have followed my adventures in 3D printing over the last couple of years, you know my MakerBot Replicator 2 can be temperamental, and prints fail more often than they succeed. This was the case when I attempted to print the ears I found on Thingiverse.

The final attempt actually caused the printer head to clog and take the printer down until I could get it repaired. With our Munchkin Land recording session quickly approaching, and a family trip out of town locking my schedule, I turned to the local university’s Maker Space to see if they could print a pair of ears for me. Unfortunately, the didn’t have a flexible filament, but they could use the PLA filament on hand to get the ears to me by Monday morning.

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Total cost for the printing – $13.00.  I think that is a bit high, but from what I can tell, the Maker Space was able to print the ears without a single failure.

I took the ears, traced the outline on the foam head, then cut a space for the ears to sit. I glued the ears in place, and because the ears are slightly larger than normal, I taped the microphone earpieces into place.

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The result isn’t pretty, but it does work.

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There are a couple of things I have noticed on playback of the recordings. First, the audio has a bit of an echo to it. This could be because we are recording in a very large room with flat walls on two sides. Second, there is a bit of a ringing in the files. I don’t know if this is because the ears are a rigid PLA instead of a flexible material, or if it is the post processing I’m doing to the file. Both of these aren’t a big deal because the end result is still  the immersive experience that I want.

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I do wonder what audience/fan reaction to these recordings will be. For the last five years ,the audio quality of the Major Spoilers Podcast Network of shows has been (in my humble opinion) top notch, with little to no noise affecting the experience. I have often complained that audio quality is an instant turn-off for me, and I though I have never called out a podcast specifically, I wonder if the change in quality will have fans complaining.  I hope not, because these recordings are really different than simply placing a single microphone in the middle of the table to pick up a role playing session.  This is an immersive experience.  I have shared a couple of the episodes with our $40 and higher Patreon Members (http://patreon.com/MajorSpoilers), and early responses have pointed out the echo and the ringing, but the immersive experience, and the story that is being told, outweigh those problems according to those listeners.

So what is next?

There are a couple of things I am going to try to improve the audio quality of the gaming sessions.

First, I’m going to replace the PLA ears with a pair of silicon ears I purchased for $25.00 from Amazon. Next, since we are in that time of year when it isn’t too cold or too hot, I’ve asked the family to forego A/C or heat while we record, as the HVAC unit in the house does make a lot of noise that was picked up during the first two sessions. Third, I’m going to move the head from one end of the table to the middle of the table. While I think the end of the table makes more sense from the environmental standpoint, having consistent audio levels from everyone around the table is probably more important. In the end, the listener will feel they are sitting in the middle of a circle instead of at one end of the table.

Also, I’m going to test/review a more professional binaural microphone that costs several hundred dollars to see if there is a huge difference between it and my home-brewed system. I’m betting my system will be just as good as one that can cost $2,000.  I will share my results and experiences with you, but for now, here is the cost breakdown for my system compared to the high-end mic:

STEPHEN’S BINAURAL MICROPHONE

  • Microphone – $89.00
  • Foam Head – $7.00
  • 3D Printed Ears – $13.00
  • Total Cost – $109.00+tax

NEUMANN MICROPHONE (B&H Photo/Video)

  • Microphone+Head+Case – $7,999.95+tax

TOTAL SAVING – $7,890.95

One thing I’ve noticed over the years of producing audio programming for online distribution is listeners are happy to accept what is “just good enough.” When my $109.00 setup works nearly as good as an $8,000 system, I’m going to go with the cheaper alternative.

Why am I doing this?

Beyond the Naturscape files I want to record, I really believe that the future of real play podcasts (and podcasting in general) is a more immersive experience. Whether it is audio only, or a 360-degree (or variation) video, being able to record with a set up like this is the next step in podcasting and online entertainment delivery. I haven’t done a lot of research into podcasts that are doing this, and besides the AMSR and binaural biofeedback videos on YouTube, I’m not seeing a lot of actual production using this audio recording process. While I’m several months away from releasing our Munchkin Land recordings officially, I do believe Major Spoilers is the first to record a gaming session this way, and may be the first to release a real play podcast when the episodes do release.

I would very much like to hear your thoughts on this audio experiment, ways to improve the audio, or even if you agree or disagree that binaural audio will be the future of real play gaming podcasts.

 

 

Stephen Schleicher

Stephen Schleicher is one of those guys that has always loved comics but never got into them until really late in life - like high school in the 80s. He just missed the Crisis on Infinite Earths, but has been around for every major crossover since. Stephen knows his way around video and film production having been a director, producer, editor, and motion graphics artist for projects ranging from small promotional pieces for Wachovia all the way up to regional videos for the Division of Emergency Management. As a prolific writer, Stephen began his career writing for the Digital Media Online community of sites, including Digital Producer and Creative Mac covering all aspects of the digital content creation industry. He then moved on to consumer technology, and began the Coolness Roundup podcast. A writing fool, Stephen also freelances for the Sci-Fi Channel's Technology Blog. When not writing, Stephen shares his knowledge as a tenured faculty member at Fort Hays State University. Still longing for the good ol' days, Stephen launched Major Spoilers in July 2006, because he is a glutton for punishment. Favorite Writers: Mark Waid, Geoff Johns, Paul Dini, Adam Beechen, Bill Willingham, Matthew Sturges Favorite Artists: Dan Jurgens, Alex Ross, Adam Hughes, Freddie Williams III

3 thoughts on “Building a Binaural Microphone (Part 1)

  • January 7, 2017 at 9:19 pm
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    I know what my next project is. I am listening to “a yellow Light” and love the sound quality. Keep up the good work Trailblazer.

  • January 8, 2017 at 12:12 am
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    I don’t know about trailblazer. Apparently in 2007-08 there was another podcast doing a binaural RPG Cthulhu podcast, that I only just heard about today. Also, right around the time we originally recorded the game play (October 2016) a few audio drama podcasts suddenly surfaced with announcements that they would be doing their shows in binaural audio. Of course back when I was a kid (in the ’80s) The Cabinet of Dr. Fritz was produced for NPR that blew me away…especially the binaural audio adaptation of Stephen King’s The Mist.

    I think what this boils down to, is the key point in the article – cost has come down and technology has improved that anyone can do something like this. I don’t think that means EVERY podcast should do this – right tool, right time, should always be the driving force. In this case, the bizarre, frightening nature of Lovecraft’s Cthulhu mythos, and the story being told by Dr. Will, made this the perfect tool to present the story in a bizarre, hopefully frightening way.

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