1. Why Your Own Recording Can Sound Surprising
You play back a recording and hear a voice that feels different from what you expected. This is a common experience. If a friend says, "That is your usual voice," you might feel even more unsettled. If you are curious about this, the University of Tokyo has published an easy-to-read explanation that you can look up later [1].
2. Two Paths Sound Takes to Your Ears: Air and Bone Conduction
There are two ways sound reaches your ears. One is "air conduction," where vibrations in the air travel to your eardrum. The other is "bone conduction," where vibrations travel through your bones [1]. When you hear your own voice normally, you hear a mix of both types. However, a recording mostly captures the sound that traveled through the air [1]. This difference is the basic reason why recordings sound "strange" to you.
3. Why Other People Hear a Voice Like Your Recording
This is the most surprising part. The voice that other people hear is also air conduction, the same type of sound as what is on the recording [1]. This means only you hear the extra resonance from your bones. Everyone around you hears your voice through air conduction. Your "own voice" sounds slightly different only to you. Note that "same air conduction" refers to the path the sound takes. Differences caused by microphones or speakers are a separate issue.
4. How Bone Conduction Changes the Sound of Your Voice
How does bone conduction change the sound? A 2023 study notes that bone conduction is thought to act like a low-pass filter, letting lower frequency sounds pass through more easily [3]. You might have heard that "bone conduction is low sounds." However, a Swedish study tested 10 sounds (phonemes). It found that for many sounds, the bone conduction part was stronger than the air conduction part in the range of 1–2 kHz (1000–2000 Hz) [2]. The relative strength of bone and air conduction changes depending on the frequency and the specific sound being made. It is difficult to simply say "bone conduction is only low sounds" based on this experiment. The University of Tokyo also notes that humans can hear frequencies from about 20–20,000 Hz, and our ears are less sensitive to low sounds [1]. However, there is not enough material to directly connect this fact to the bone conduction explanation.
5. How Hearing Aids Relate to Hearing Your Own Voice
A 2010 paper states that the relationship between the strength of air conduction and bone conduction components has not been fully determined [2]. This relationship is important for people who use hearing aids. Hearing aids affect both air conduction and bone conduction, which changes how users hear their own voices. The relationship between bone and air conduction that this paper tried to measure is seen as a foundation for helping in these situations.
6. Does a Recording Simply Sound Lower? Why the Answer Is Not So Simple
From the previous sections, you might think, "My recorded voice should sound higher because I miss the bone conduction." But the story is not that simple. A study in the Canadian Acoustics journal reported that many people felt the pitch of their recorded voice went down [4]. This does not fit well with the strong hypothesis that bone conduction alone explains the difference. The study says people cannot accurately judge the features of their own voice, and factors other than air/bone conduction differences or gender may be involved. This study does not deny the bone conduction theory but adds that it is not enough on its own. It is better not to remember "recordings sound higher" as a fact that applies to everyone.
7. Can a Bone Conduction Headset Help You Recognize Your Own Voice?
In the 2023 study, when participants used bone conduction headsets to add vibration stimuli, they became better at telling apart their own voice from other people's voices [3]. However, there was no difference in telling apart other people's voices from each other (known vs. unknown voices). The results are limited to tasks involving one's own voice. This study consisted of three experiments with 16, 16, and 52 participants respectively (in the 52-person experiment, 9 were excluded from the main regression analysis due to control task performance). The vibration from bone conduction may be one clue for recognizing your own voice.
8. Try It Yourself: A Way to Test Voice Differences Today
So far, we know the difference between the two paths is the main explanation, but it does not explain everything. Here is what you can do today. Before recording your voice, write down on paper whether you expect it to sound higher or lower. After listening, compare it with your prediction. Since one study found many people felt the pitch went down, seeing what you experience is useful data [4]. You can also try speaking without covering your ears, then lightly cover your ears with your palms and speak again to compare how it sounds. Do not press hard. Since the sources in this article do not determine exactly what changes, just write down your observations: what changed or what did not change. The University of Tokyo's "Simple Question vs. UTokyo" explanation is a good starting point in Japanese [1].