You might have heard of binaural audio, but what is binaural audio, and how is it different from stereo? In this article, I’ll break down the science of binaural audio and share my hands-on experience capturing wildlife soundscapes and nature sounds.
Binaural audio is a powerful recording technique that captures the three-dimensional space of an environment with incredible realism. When you listen to a binaural recording, it feels like you’re truly there—experiencing the sounds just as they happened. This true-to-life quality is why it’s often called 3D audio.
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How Does Binaural Audio Achieve Realism?
Binaural audio is all about recreating how we naturally hear the world. To achieve this, binaural recordings use a dummy head fitted with two microphones placed inside the ear canals of artificial human ears—designed to match real human ears in size, shape, and texture. The outer ear, known as the pinna, gathers, amplifies, and directs sound waves into the ear canal (or microphone), creating subtle delays that help us identify where sounds are coming from.
The dummy head also mimics our own head’s physical properties, acting as an acoustic baffle. It filters incoming sound frequencies, blocking higher frequencies while allowing lower ones to pass around. This filtering, combined with differences in sound level and arrival time between the two ears (known as Inter-Aural Level Differences and Inter-Aural Arrival Time Differences), helps create an incredibly realistic sound experience.
These combined effects are known as Head Related Transfer Functions (HRTF), and they are unique to each person. Ideally, recording with your own head would deliver the most accurate binaural effect because it matches your specific HRTF. However, in practice, using a dummy head is more practical—it minimizes handling noise and keeps the recorded sound stable without shifting.
The Neumann KU-100 strives to address the wide variations found in human head shapes and sizes. It is praised for its optimization and precision of the stereo field.
One key thing to understand about binaural recording is that it captures sound from all directions—including above and below. This creates an incredibly immersive surround sound experience. Unlike traditional surround sound setups, binaural audio only requires two channels to achieve full immersion. Even better, you don’t need any fancy equipment or multiple speakers to enjoy it—just a good pair of headphones. In fact, headphones are the ideal choice for getting the most out of binaural recordings.
While it’s possible to listen to binaural audio through stereo speakers, you’ll lose some of the magic. The accuracy of the sound image and the richness of the frequencies get compromised. This happens for a few reasons:
- The listener’s head creates a secondary acoustic shadow.
- Speakers produce unwanted acoustic crosstalk that headphones don’t have.
- Room acoustics interfere with spatial cues, messing with the accuracy of arrival times.
All of these issues are avoided entirely by using headphones, making them the perfect way to truly experience binaural audio.
Is Binaural Audio the Same as Stereo?
Binaural audio is technically a type of stereo, but it’s captured very differently from traditional stereo. The key difference is that binaural audio uses Head Related Transfer Functions (HRTF), which are essential for recreating a realistic, three-dimensional experience. These HRTFs are mostly absent in conventional stereo recordings.
Traditional stereo can provide a wide soundfield, but it captures sound primarily on a flat, horizontal plane—meaning it picks up sound from the left and right but doesn’t account for what’s above or below. Stereo also doesn’t inherently capture the depth of sounds coming from behind unless the microphone setup is specifically designed for it, depending on the microphone’s polar pattern and the stereo technique being used.
Like binaural recordings, stereo also uses two microphones, but they can be placed at different angles and distances. How far apart they are and how they’re angled has a big impact on how wide or narrow the stereo image sounds. You can use this flexibility to your advantage—making something sound hyper-real and expansive, or close and intimate, depending on your goal.
Traditional stereo techniques don’t typically use a baffle between the microphones. If they do, the baffle creates an acoustic shadow that blocks certain sounds, similar to how the human head works in a binaural recording. This setup is often called ‘pseudo-binaural.’ Examples of this method include the Jecklin disc and the Crown SASS microphone.
Take a moment to listen to this recording encoded both as stereo and as binaural. To me, the binaural version feels more open and natural. Of course, I had the benefit of hearing the actual environment. What do you hear? Do you notice a difference?
Is Ambisonic Audio the Same as Binaural?
Ambisonics is a different kind of recording technique that captures sound using anywhere from four to sixteen channels. It was first conceptualized by Michael Gerzon in the 1970s, but it’s only in recent years that Ambisonic recording has started to become practical and widely used. The cool thing about Ambisonics is that it can be decoded into a variety of formats—whether it’s its native Ambix format, surround sound, stereo, or even binaural. So, in short, it’s like binaural audio, but with much more versatility.
One big advantage of Ambisonics over binaural is that it creates a rotatable sound image. When you listen to an ambisonic recording, the sound shifts as you move your head—almost like how a 360-degree video changes when you look around. The volume levels also adjust in real time, making it feel incredibly immersive. On the other hand, binaural audio is more static—think of it like a 3D Viewmaster, where the sound stays fixed no matter how you move your head.
360 Degree Video with Embedded Ambisonic
Recent YouTube updates have disrupted ambisonic playback, and it now only works occasionally with Chrome. If the sound does not rotate, ambisonic playback is not working.
Personal and Practical Recording Experience
Let’s dive into some of my personal experiences with binaural recordings. I’ve been experimenting with binaural audio since the mid-1990s, starting out with microphones from Sound Professionals and a Sony minidisc recorder. Despite its limitations, that small setup worked wonders during a trip to Germany. I managed to capture the vibrant atmosphere of the Hofbräuhaus beer hall and a violinist playing on the S-Bahn. Although those moments happened decades ago, binaural audio makes it feel like I’m right back there every time I listen. It’s amazing how it can transport you, making the experience come alive again.
The power of binaural audio lies in its realism—it captures environments like nothing else. But there are challenges too. Recording with a dummy head can be bulky and awkward. You’re sure to draw attention from curious onlookers who might interrupt with questions. This isn’t much of a problem when you’re recording in nature, but in public settings, it can get tricky. A simpler approach is to use your own head as the acoustic model. A smaller, less noticeable recording setup keeps people from getting too interested. Just make sure you stay perfectly still while recording—any movement could cause shifts in the sound image.
One practical modern approach I’ve found is to simply stare at your phone mindlessly. People will assume you’re preoccupied with social media. Plus, if you’re using a recorder like the Zoom F3 that has an app, you can monitor volume levels while staying incognito
Recording Gear Challenges
From my experience, using high-quality equipment definitely makes for better recordings. The challenge with binaural microphones, though, is that they’re often quite small, which means they can struggle with low-frequency sounds and have higher noise levels. They’re fine in louder environments, but when it comes to capturing the subtle, quiet sounds of nature, they don’t always perform well—especially if paired with cheaper recorders. Even popular mics like the DPA 4060, which some nature recordists swear by, tend to be a bit too noisy for my taste.
But don’t let that discourage you from diving in and making your own binaural nature recordings. As photographers often say, ‘The best camera is the one you have with you.’ The same goes for audio gear. I always keep a simple Zoom H1n and some Roland mics in my car to grab whatever sounds come my way—imperfections and all. Just get out there and start capturing—you’ll be amazed at what you can achieve!
Binaural Recording Hybrids
Many of the recordings at Wild Soundscapes still use traditional stereo techniques like ORTF, Spaced Pair, and Mid-Side. While I’ve moved away from Mid-Side for nature recording, ORTF remains a favorite of mine and others for its impressive soundstage accuracy. Sometimes, I also use a spaced pair of microphones to get a wider soundstage, though this comes at the cost of some localization accuracy.
One thing I’ve noticed is that reverberant, vibrant atmospheres make for more exciting recordings. When sound bounces off trees or rock walls, it adds incredible depth and space. This is true for stereo recording in general, but there’s something magical that happens when using binaural techniques—it adds an extra dimension that’s hard to beat.
This pseudo-binaural setup gives you some of the HRTF benefits of true binaural recordings, but with a balanced frequency response and much less noise. It doesn’t fully capture sounds from the vertical axis, but once I sort out better wind protection, it’s likely going to be my go-to setup. I’ve heard that Lang Elliot at Music of Nature uses a similar approach with Sennheiser microphones, and I know a lot of nature enthusiasts create their own version of the Crown SASS.
Other pseudo-binaural techniques include using a Jecklin disc or an Olson Wing. These are also baffled stereo techniques that capture some of the HRTF effects of binaural recording. I’ve been experimenting with exploring Curt Olson’s “Wing” design, and I’m really impressed with how simple and effective it is.
A few years ago, I picked up a Rode NT-SF1 ambisonic mic. Truthfully I don’t use it much. While I can decode ambisonic recordings into binaural, it just doesn’t have the depth I’m looking for. Plus, managing the multiple channels and post-processing is a kind of a hassle. That’s why I tend to stick with other options, though I’m excited to try some of the newer Higher Order Ambisonics microphones like the SPC mic from Harpex.
Binaural Sound Examples
Use the player below to hear examples of binaural recordings. Notice how the environments acoustics play a roll in the envelopment of sound. To experience the binaural effect, you need to wear headphones.
I hope you now have a better understanding of binaural audio—its unique qualities, how it differs from traditional stereo, and its amazing ability to capture sound in a lifelike, three-dimensional way. I encourage you to try making your own binaural recordings and share them. Watching the reactions of people hearing binaural sound for the first time is always such a joy. And, of course, you can also send them to explore the Wild Soundscapes website!
Happy Listening!
