Why Some Headphones Need to be Charged

Why Some Headphones Need to be Charged (and Others Do Not)

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Headphones these days have become increasingly complex.  With the invention of smart technology—bluetooth connectivity, noise-cancellation, and enhanced speaker drivers—consumers are presented with far more options than the standard wired variety.

But why is it that some headphones need to be charged, while others work without any power source at all?

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Time to Get Scientific

Standard headphones (as in ones that need to be plugged in via the 3.5mm or 6.35mm headphone jack) work without power because they contain small passive speakers.

Simple Diagram of a Speaker

Simple Diagram of a Speaker

The design of larger speakers and headphones are fundamentally identical. But while a large speaker needs an amplifier, a small passive speaker does not require an external power source in order to operate. The audio signal from your source device– be that a phone, computer or whatever– produces enough electrical energy to move the speaker cone.

For example: Any music device, like mp3 player, generates a line-level audio signal which is sent to the speakers in the headphones.

A line-level signal produces a relatively small amount of electrical energy. There is not enough power to move a large speaker cone without an amplifier, so the speaker size is limited and the volume output is low. This is obviously not ideal to fill a room, but it does make it ideal for personal listening through headphones.

So Why do Modern Headphones Need to Be Charged?

Headphones that need to be charged are a new phenomenon. This actually has more to do with the addition of smart features included on the product rather than the speaker itself.  Here are some common headphone manufacturers along with the reason their products require batteries:

Beats:  Amplification

Beats by Dre

Beats are popular headphones among DJ's and hip-hop enthusiasts because of their heavy accentuated low-end.

Beats headphones achieve such a heavy bass thanks to the built-in active amplifiers. These amps can drive the speakers harder and louder than traditional passive headphones, but it requires an external power source like a built-in battery.

Bose:  Active Noise Cancellation

Bose Quiet Comfort Headphones

Bose headphones, (like the Bose QuietComfort 35) and other brands with active noise cancellation technology have additional circuitry such as electret microphones built into the unit. These components require an external power source in order to operate.

Wireless / Bluetooth Headphones

Wireless Headphones

Any wireless headphones (like the COWIN KY02 Earbuds or the Jabra Elite 85h) connect to your device via bluetooth. Bluetooth requires an external power source in order to power the connection.


Modern technology built into headphones gives you a plethora of customized options. It gives you freedom and flexibility not available in traditional wired kinds.  The technology comes at a cost though.  While you are not tethered to your music player, you are still tethered to the battery charger—a fact that may not hit you until you find yourself in the middle of a long plane flight with a dead battery.

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