How does a speaker work? Keys to understanding audio technology

The first ever recorded voice did not speak — it sang. In 1860, Parisian inventor Édouard-Léon Scott de Martinville debuted his "phonautograph," with the folk song "Au Clair de la Lune." Within just half a century, electrically amplified sound quickly grew from a fringe novelty to a technological necessity of the modern world, capturing the voices of many and transmitting them to all corners of the globe. The key to this achievement? The ever-increasing capabilities of speaker technology.

How does a speaker work, exactly? It's always a good idea to learn the basics — especially if you intend to invest significant money into audio equipment. With a little knowledge, you can make smarter choices on the right speakers for your unique wants and needs.

Capturing and recording sound is only the first half of the audio process. To tap those signals and transform them back into audible sound takes a loudspeaker. Most speakers today still depend on two fundamental elements: a transducer — also called the electrodynamic driver — to transform the captured electrical signals back into analog sound waves, and a speaker cone to direct them outward.

The speaker driver relies on the same fundamental structure today as when it was invented in 1925, using a wire voice coil suspended in a magnetic field. When the coil receives the electrical signal, it causes the cone to move back and forth, creating a pressure wave, better known as a sound wave. That also happens as the device receives radio waves from more distant sources.

In the 1950s and 1960s, engineers expanded that configuration by dividing the transducer into multiple drivers, with each one focused on a specific frequency — tweeter for high frequencies, woofer for bass, and midrange for everything in between. The result was a higher fidelity to the original audio source, and that refinement remains ongoing, such as in the development of subwoofers to deliver a more dynamic range of bass.

From CDs to the internet, the 1990s caused a revolution in how sound systems work, primarily due to a new digital signal. Analog sound is transmitted in electric pulses of varying amplitude, while digital sound transmits the signal in a series of 1s and 0s. This required new playback devices, and a new crucial component: the digital-audio converter, which transforms the digital signal into an analog wave so we can still hear it.

Bluetooth® and Wi-Fi® technology marked the next major step in speaker development and began to expand speaker capabilities and functions by the mid-2000s. As their functions and capabilities matured, Bluetooth range has increased drastically, as seen in Bose Bluetooth speakers, portable PA speakers, and smart speakers.

Not only do they play music, podcasts, and soundscapes from any wirelessly connected Bluetooth device — or from your favorite streaming services via Wi-Fi — Bose portable speakers have hours of playback without plugging in, thanks to the rechargeable power source.

The portability of wireless Bluetooth speakers also means you can expand coverage to wherever you are, whether that's pulling weeds in the garden or gathering with friends on the patio. Don't worry about wear and tear either, as all Bose speakers are built with high-quality, durable materials. Some, like the Bose SoundLink Flex Bluetooth® Speaker are entirely water and dustproof.

Ever since Amar Bose, founder of Bose Corporation, graduated from MIT in 1956 with a PhD in electrical engineering, we have pursued improvements in material, design, and performance for speakers and audio systems.

From the 360-degree projection of the , to the extreme portability and durability of the Bose SoundLink Micro Bluetooth® Speaker, or the outdoor output capacity of the Bose S1 Pro+ Portable Bluetooth® Speaker System, we aim to push the boundaries of innovation and the science of sound.

A Bose smart speaker like the Bose Smart Ultra Soundbar also takes positioning into account through ADAPTiQ technology, which adjusts the sound levels according to a digital analysis of the space and furnishings. SimpleSync technology elevates this further by pairing two Bose speakers — even in different rooms — for expanded coverage or creating a stereo mix between the two for a richer musical experience. If anything, features like these speak to the creativity that keeps Bose forever at the cutting edge, if not leading it. For further proof, simply turn on the speaker and listen.

The entire purpose of a speaker is to enhance and empower the sounds you love most, but those made cheaply and quickly may simply achieve the opposite, leaving you feeling deflated and frustrated. With Bose speakers, you can always be sure of the best — and even beyond that, as Bose continues to revolutionize wireless speakers and audio technology. Not only does that transmit a "wow factor" to your favorite songs, but the vibrancy and depth driven by Bose speakers may feel like you're hearing them for the first time all over again.