Acoustic speakers or loudspeakers are systems capable of sound diffusion through a transduction process, meaning the conversion of electricity into sound waves. There are many different types, varying in size and functionality.

The Origins of Acoustic Speakers

Today, acoustic speakers are everywhere. Speakers can be found in computers, TV remotes, MP3 players, and more… we are literally surrounded by them. However, it has taken a lot of time and ingenuity to achieve these results. The origins of loudspeakers date back more than a century.

The First Loudspeakers

The history of loudspeakers begins alongside the invention of the telephone, and it was within a telephone that the very first speaker was placed in the second half of the 19th century to reproduce the voice of the interlocutor.
After an uncertain attempt by Johann Philipp Reis, the first speaker capable of decently reproducing speech was patented in 1876 by Alexander Graham Bell. From then on, many inventors – including Edison and Short – worked on perfecting this revolutionary system, each contributing to improving its quality compared to previous models. Specifically, in 1877, Von Siemens created an electromagnetic coil-based speaker following Bell’s design, but it was unsuccessful. Today, a century and a half later, Von Siemens’ design is the only type of loudspeaker still in use.
About fifty years later, in 1924, Chester Rice and Edward Kellogg patented technology using a moving coil, driven by a magnet and induction, capable of also producing sound waves. Thanks to this innovation, in 1926, Rice and Kellogg were able to commercialize Radiola: speakers with much better quality than others on the market at the time. This product significantly reduced audio distortion and improved sound quality, making Radiola very popular and the first battery-free radio that allowed listeners to enjoy news, sports, and radio soap operas.

The Revolution in Cinema

Soon, speakers made their way into the world of cinema, marking the end of silent films and the rise of sound films.
In the 1930s, researchers and manufacturers continued to refine loudspeakers until, in 1937, Metro-Goldwyn-Mayer introduced the Shearer Horn system, which used a single horn and two compression drivers for high-frequency sounds. This marked the birth of high-fidelity sound, or Hi-Fi, which is still in use today. In 1943, Altec Lansing invented duplex drivers and the 604 speakers – also known as the Voice of the Theater – which delivered very clear sound even at high volumes; this system became the standard in the film industry and is still used.

Reducing Size

In 1954, Edgar Villchur invented acoustic suspension for duplex drivers, a system that improved bass quality in smaller cabinets.
This was a pivotal advancement in stereo recording and playback, as it was previously challenging to record high-definition music while controlling bass. This discovery also led to a focus on creating smaller cabinets without compromising sound quality. To understand the speed of these advancements, consider that in the 1980s people carried heavy portable stereos on their shoulders, while by the 1990s, they used tiny Walkmans clipped to their belts.

Integrated Amplification in Speakers

An important milestone was the invention of the two-way active system by Meyer Sound Laboratories in 1980. This was an amplified speaker with separate drivers for high- and low-frequency sounds and crossover circuits to power signals for both. This new amplifier could cover the entire sound spectrum thanks to its wide frequency range.
Subsequent technological advances led to the three-way system, adding a mid-frequency driver and a subwoofer to handle very low frequencies.
Continuous discoveries, experiments, and further technological progress have rapidly occurred in recent years, enhancing both size and power. As a result, today, we can enjoy car radios, music on smartphones, and wireless Bluetooth speakers.

Functionality, Components, and Materials

First, it should be noted that the term speaker refers to the entire structure, comprising the cabinet – also called the box or enclosure – which houses the loudspeakers. The loudspeakers are one of the most critical parts, acting as transducers that convert audio signals into sound.

Before delving into the mechanism that allows this conversion, let’s examine the components of loudspeakers.

Components and Materials

Loudspeakers are the heart of acoustic speakers, as they are primarily responsible for producing sound. Each loudspeaker consists of:

• Diaphragm: Usually conical, it vibrates to produce sound waves. Its weight and size vary depending on the frequency range it needs to reproduce. Diaphragms can be made of cardboard or synthetic materials.

• Basket: A circular structure that contains all the loudspeaker components.

• Suspension: A ring that connects and secures the diaphragm and basket.

• Coil: Made of metal, it receives the electrical signal from the amplifier. It is located at the center of the basket.

• Magnet: Positioned opposite the coil to interact with it through the magnetic field.

How Do Acoustic Speakers Work?

When the electrical signal – amplified – reaches the coil, it generates a magnetic field that interacts with the magnet’s field. This causes the coil to move, along with the diaphragm surrounding it, which produces sound waves corresponding to the received signal frequency.
The diaphragm plays a crucial role, as its size and shape affect the sound frequencies it produces. Some loudspeakers are designed for high tones – tweeters, often dome-shaped rather than conical – while others handle mid-tones (mid-range) or low tones – woofers and subwoofers. The cabinet also influences the final sound quality, and they come in various types and sizes.

Types of Acoustic Speakers

There are different types of acoustic speakers/loudspeakers, varying in size, power, amplification method – active or passive – number of ways (i.e., the frequency bands produced by the crossover), quality, materials, and more. The greater the number of ways, the more loudspeakers there are, and consequently, the larger the cabinet.

It’s essential to understand terminology: the term acoustic speaker is often used as a synonym for passive speaker, referring to a speaker without an integrated amplifier.

Size

Based on size, we can distinguish between floor-standing speakers – which can be placed directly on the ground, often featuring two, three, or more loudspeakers and are quite large – and bookshelf speakers – much smaller, designed to be placed on specific stands or shelves. Portable speakers, PC speakers, and wireless speakers fall into the latter category.

Everything depends on the audio system being built and its intended use: home theater setups ranging from 2.1 to 7.1, with Dolby Surround or Atmos technologies, to stereo speakers for music or home recording purposes, such as studio monitors.

Speakers

As mentioned earlier, speakers can differ in the number of loudspeakers. Options include:

• Three-way speakers: Comprised of loudspeakers capable of capturing high, mid, and low-frequency ranges – tweeters, mid-range, and woofers.

• Two-way speakers: Featuring two loudspeakers, one for high frequencies and one for low frequencies.

• Single-way speakers: A single loudspeaker reproduces the entire range.

Construction Technology

There are primarily two techniques:

• Acoustic suspension: In this mode, the speaker is completely sealed. This means the air inside the cabinet does not communicate with the outside, exerting stronger pressure based on the diaphragm’s movement.

• Bass-reflex: This speaker has an opening at the bottom, allowing air moved by the diaphragm to exit and create waves that enhance low frequencies.

Acoustic Speaker Prices

As we’ve seen, acoustic speakers can vary greatly, so prices also vary widely depending on features, component quality, number of ways, size, and more. Generally speaking, prices range from €100 to €1000.

It’s advisable to research the product that best meets your needs before purchasing. If the desired model is too expensive, you might consider exploring the used market.

Among the best brands in the acoustic speaker sector are Yamaha, Indiana Line, Dali, Klipsch, Elac, Wharfedale, Jamo.