Why does audio played through iem or headphones feel like it’s originating inside your head?

250610 – Repost from a My Korean Blog

Why Sound Imaging Differs Between IEMs/Headphones and Speakers

Many people tend to give simple explanations such as “the response varies with each person’s fit” or “there is no crosstalk.” In particular, the absence of the binaural effect (the spatial cues you get when listening to speakers) is often emphasized, leading into discussions about crossfeed and even BRIR (Binaural Room Impulse Response).

But is the lack of crosstalk really the entire reason why the perceived sound image seems to form inside your head?

Of course, there’s some truth to that: where there’s a cause, a result follows. However, merely the absence of crosstalk doesn’t explain the purpose and logic behind speaker XTC (crosstalk cancellation).

On one hand, people say it’s a problem because there’s no crosstalk; on the other hand, others try to eliminate crosstalk… Isn’t that odd? As noted above, the absence of crosstalk does serve as a “cause,” but is that the whole story?

Let’s run a thought experiment. (If we think in terms of IEMs or headphones, we may be trapped by preconceptions, so instead imagine speakers—after all, they’re just playback devices.) If you place speakers at 90° to the side instead of 30° in front, there is physically less crosstalk. Then, does “less crosstalk” simply mean only that there is less crosstalk?

You might picture them arranged roughly like this. But what if they were placed closer together?

Then, naturally, the sound reaching the opposite ear is greatly reduced. When in everyday life do we easily encounter sounds with such “extremely” low crosstalk?

Touching your ear canal with an ear pick, blowing air into your ear, or whispering directly into the ear—all of these are extreme cases of sound.

In reality, for crosstalk to become that low, the source must be extremely close. In other words, hearing something “inside your head” corresponds to conditions where crosstalk is absent or extremely low—i.e., a realistically achievable scenario only when the sound is so near it effectively seems internal. When you touch your ear canal with an ear pick, the sound is naturally perceived inside the ear; crosstalk is so minimal or nonexistent—a cue that it’s unimaginably close, and thus heard “inside your head.” That’s consistent with real-world experience.

So why doesn’t speaker XTC sound as if it’s inside your head? There are two (or perhaps three) reasons:

After ideal XTC, the remaining crosstalk level is not as extreme as with IEMs or headphones. Because it isn’t that extreme, it fails the cue that would make us perceive it “inside our head.” This is one reason speaker XTC doesn’t create that internalized sensation.

Head-tracking: this varies widely depending on the test tone or music, the listening scenario, and even visual cues. While head-tracking can improve spatial perception, it isn’t the primary factor here.

Pinna reflections: the way the outer ear shapes and reflects sound also plays a critical role.

(Depending on how deep you want to go, you can expand on each point—for example, explaining typical crosstalk levels after XTC versus IEMs, how head-tracking interacts with visual feedback, and how pinna reflections influence externalization. Let me know if you’d like more elaboration or adjustments in tone.)

Let’s revisit this illustration: it’s positioned right next to the ear.

No matter how the device’s response interacts with the listener, in the case of headphones, the pinna reflections—this acoustic “fingerprint” signaling that sound is arriving immediately beside the ear—remain. (With IEMs, pinna reflections are omitted entirely.)

If sound truly arrives that close to the ear, then realistically the scenarios we can think of are the same as those mentioned above: touching the ear canal with an ear pick, blowing air into the ear, or whispering directly into it.

Therefore, this condition again serves as a cue that can make the sound seem to come from inside your head.

Imagine placing speakers directly in front of you.

From the pinna onward, reflections are already different. It is not a cue of sound arriving inside your ear or right beside your face. Therefore, in most cases, the sound cannot be perceived as coming from inside your head.

This difference in pinna reflections actually carries significant weight. Even with IEMs—where there’s no crosstalk and no special EQ—if you apply a convolution that normalizes the distant frontal pinna reflections, that single convolution alone will push the perceived image outside the head. Since IEMs lack any “proximity fingerprint,” listeners perceive exactly that convolution and thus recognize the sound as external.

With headphones, however, there remains the trace of sound right next to the ear. Some compensation is possible, but because fit varies from person to person and perfect compensation is unattainable, you inevitably detect that the sound is next to your ear and it stays around the head. (This is why BRIR methods show clear limitations for headphones.)

Not long ago, when discussing target responses, I gave an example that we can similarly imagine here:

Assume a speaker is placed in front. If you attenuate the ear-gain band by –5 dB or –10 dB, would it sound like it’s coming from behind? The pinna reflection pattern already signals that “this is in front.” Of course, tonal-balance changes may alter the listening experience, and the presence or absence of reflections might slightly affect perception. But the pinna cue itself remains unchanged.

Now, let’s return to the illustration.

(Here you can re-show or refer back to the diagram to continue the discussion.)

Headphones and speakers are essentially the same. (IEMs differ somewhat because pinna reflections are omitted.)

There remains the cue that sound is arriving right next to the ear.

If you emphasize ear gain here and try to emulate a frontal response, how would that sound? Would it truly resemble a front-facing speaker? Since there’s already a cue that the sound originates from the side, what meaning does it have to follow the response of a certain distant source—even at 1 meter away rather than right beside the ear (and not as far as 2m or 10m)?

Of course, IEMs and headphones influence our listening and imagination based on their response characteristics, so they do have some effect. But what does that really signify?

Therefore, listening and adjusting according to personal preference is indeed a wise choice. However, aligning to a specific azimuth, target, or distance—when you reflect carefully on these factors—makes it hard to assign clear meaning.

(This is purely my personal opinion, but I also wonder: why are we especially sensitive to in-head sound? As in the example above, does sound reverberating in the head or arriving right next to the ear even sound “normal”? As the source gets closer, the HRTF, colloquially speaking, breaks down and becomes distorted.)

So the conclusion is that certain cues inevitably make sounds be perceived inside the head (or only around the head).

Of course, everyone may have different thoughts on this, and each opinion deserves respect.
However, anyone with a deep interest in IEMs, headphones, and speakers would likely ponder the following (as discussed above):

What are the cues (or conditions) that make sound be perceived outside the head?
What are the cues (or conditions) that make sound be perceived inside the head?
Is hearing sound “inside the head” normal? Do we perceive that as natural? — As when touching the ear canal with an ear pick, yet an instrument plays and a singer sings.

(These questions invite reflection on the nature of spatial hearing and how proximity, pinna cues, crosstalk, and HRTF behavior at very close distances shape our perception.)

Below are the links to the original Korean blog posts.

하이디션 커스텀이어폰 비엔토(VientoB) 후기 Hidition Custom IEM Viento (VientoB) Review

편한 이어폰... 외이도염, 그리고 하이디션의 비엔토? Comfortable IEM… Otitis Externa, and HiDition’s Viento?

가벼운 헤드폰, 코스Koss KSC75 짧은후기 Lightweight Headphones: Koss KSC75 Short Review

오픈형 이어폰은 돌고돌아 이어팟 (feat. 피오 ff1) The craving for open earphones always comes back to Apple Earpod

이어폰 2핀단자가 헐렁거릴때 When the 2-Pin Connector of an IEM Becomes Loose

삼성 갤럭시 버즈3 프로 짧은후기 - 유선의종말? Samsung Galaxy Buds3 Pro Short Review – The End of Wired Audio?

Equalizer APO을 위한 돌비 업믹싱 Dolby Upmixing for Equalizer APO

스피커가 사라진다, 우리가 실제로 듣고있던건 뭘까-BacchORC의 목적 Speakers Disappear: What Were We Actually Hearing? – The Purpose of BacchORC

바이노럴 가상화, 외부화에 대한 내용들 요약 Summary of Binaural Virtualization and Externalization

토핑 득삼플 Topping DX3PRO+ 펌웨어 hp err오류? Topping DX3PRO+ Firmware HP ERR Error?

왜 이어폰,헤드폰은 머리속에서 들릴까? Why does audio played through iem or headphones feel like it’s originating inside your head?