What is Stereo Imaging in Headphones?
Stereo imaging represents how precisely a headphone (or speaker) can pinpoint a direction of a specific sound.
Headphones have many different characteristics that make them individually unique. Apart from isolation, sound signature, sound quality, and soundstage, there is also a capability of how accurate they are at imaging.
What Exactly is Stereo Imaging?
In audio, the term “imaging” or “sound localization” stands for the ability to accurately pinpointing the direction of individual sounds in an audio recording. That is why you normally hear the singer somewhere in front of you, while slightly on the right the guitarist is jamming his solo.
If you pay close attention when listening to music, you will realize that instruments sometimes change their position. They can move from left channel to right, giving you a feeling of sound floating around your head. On some occasions, you can also tell the sound’s size, and even shape.
However, not all headphones have very accurate imaging. Sound localization is excellent when you carefully listen to a song, and you can tell exactly where all the instruments are and how far away they are from each other.
How Do Headphones Know the Location of a Sound?
As with many things in audio, determining a location of the sound happens inside the studio. Audio engineers determine how their mix should sound like, how well it will utilize the soundstage, and where a specific element is placed inside a stage.
If you listen to a lot of very old music (from 60’s or older), you might hear sounds coming from dead center, and completely left and right. That’s because, at that time, stereo started replacing previous mono sound systems. Therefore, sound engineers needed to experiment a little with the stereo image to improve the listening experience, but they didn’t know exactly how to do it.
Nowadays, mixing methods have improved significantly, meaning that almost all songs you’re listening to have accurate imaging information. However, the quality of headphones determines how accurately you’re going to hear that imaging info.
Stereo Imaging vs Soundstage: What’s the Difference?
The soundstage represents the distance of the sound, whereas the imaging stands for the sound’s direction. First, you know how far away a violin is, but thanks to sound localization, you know precisely where it’s coming from.
One essential difference between the two terms is that while imaging is determined by the sound engineer, the soundstage is not. The latter is something that headphones need to create on their own either by design, tuning or with a software’s help (virtual surround sound).
The soundstage is the three-dimensional space around you, where instruments are located.
A headphone with a small stereo field gives you a feeling as if instruments are playing inside your head. On busier tracks, such as live recordings of orchestra, instruments can get mushed together since they’re too close to one another.
In contrast, a pair of headphones with a big soundstage can further place those instruments away, giving you an experience as if you’re actually in a concert hall.
On the other hand, imaging tells the sound’s direction, the way from where it’s coming from. Your brain later combines both pieces of information, location, and direction, giving you a much more realistic three-dimensional audio experience.
How Headphones Achieve Stereo Image?
Sound engineers use tricks to fool your brains into thinking that a sound is coming from a specific direction. To do that, they use some basic psychoacoustic principles, like audio delay.
To understand how a delay can help pinpoint a location, let’s look at a human head. Our ears are spaced apart and positioned to pick up noises from left and right. When someone speaks to us from the right, the sound first hits the right ear, while our left ear receives that sound with a slight delay. Our brains calculate that delay in real-time to tell us at what angle that sound came from.
Sound engineers use this trick to move instruments around the soundstage, giving them an exact location. They’re changing the track channels by carefully applying frequency, phase, and amplitude mismatch. Later on, our headphones need to replicate that information, giving us the sound experience as the artist intended.
How Headphones Affect Imaging?
Not all headphones have good imaging, and it has a lot to do with their treble quality. With the articulate high-frequency response, instruments are presented with greater detail, which is why they stand out in the mix. It’s quite common that headphones with sharp treble have excellent imaging. For example, closed-back Beyerdynamic headphones, known for their bright sound signature, have superior imaging. Although bring headphones can cause listening fatigue. LINKZ
The position of the drivers can also affect the imaging accuracy. Compared to full-sized stereo room speakers, each speaker needs to face you at a 30° angle. Only then you can experience its full imaging potential. You can see the same kind of angled drivers in headphones. In-ear monitors don’t share the same problem since they go straight into your ear canal.
Speaking of in-ears, because of their in-ear design they can’t create a huge soundstage, which makes them overall better at imaging. More on that in our next section.
Drawbacks of Perfect Imaging
Many headphones with excellent imaging capabilities are somewhat intimate, meaning they lack in the soundstage. That’s because songs are not mixed for incredibly vast soundstage. Since the latter is something that headphones need to create independently, imaging accuracy can get slightly lost in the process.
Youtuber Joshua Valour explains this phenomenon with a simple rubber band:
The circular design of the band represents the soundstage, and at first, it’s small. Drawing a small dot on the rubber shows an accurate position of the sound (imaging). However, as you start stretching the rubber band (expanding the soundstage), that dot starts getting bigger, showing that its position isn’t as accurate as before.
That is why you have to choose between having a big soundstage or precise imaging. Thankfully, there are plenty of headphones that can give you a little bit of both.
Should You Care About Accurate Imaging?
Accurate headphone imaging highly depends on how you like enjoying your daily content.
- For headphone lovers and sound engineers, accuracy is their first priority. Especially for the latter, since the quality of the final product depends on headphones’ accuracy.
- Another group of people that also want great sound localization are competitive gamers. While a big soundstage gives you a better gaming experience, imaging can tell the listener where precisely are his enemies. Just by knowing that, you have an advantage over your opponents.
- In contrast, if you’re a more casual user, things like that shouldn’t matter much. The fact is that all headphones can portray somewhat decent imaging, which is more than enough if you only need to play your music in the background.
Also, price doesn’t play a role in how well your headphones can image. You can find a pair with great headphone imaging in all price ranges.