Exploring Common DIY Terminology (work in progress)

Preface

I started this article with the intention of offering a guide to DIYers, mostly those new to the field, that defines and explains the terminology you often see in discussions on the topic of DIY loudspeakers. Now, I have plenty of learning to do myself, and am under no illusion that what I do know is complete and correct. Because of this, I want these articles to be living documents. By that I mean, I'd like the DIY community to offer input on each definition to expand and clarify...

Anechoic Chamber

A space or area (often a large room for industrial applications) that is designed to eliminate reflected sound, as well as eliminate sound from outside the chamber. The noise floor inside an anechoic chamber is very low, typically close to the threshold of human hearing in the 10–20 dBA range, and sometimes much lower (the noise floor of a typical home is approximately 40 dBA). In acoustics, such a room is used to measure loudspeakers and individual loudspeaker elements....

Alnico (magnet)

An alnico magnet is a type of permanent magnet known for its strong magnetic properties and high-temperature stability. The name "alnico" is derived from its components: aluminum (Al), nickel (Ni), and cobalt (Co). Alnico magnets were first developed in the 1930s and have been widely used in various applications, including loudspeakers, guitar pickups, sensors, and industrial machinery. Key characteristics and features of alnico magnets include:

1. Magnetic

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Dispersion

Dispersion refers to the way sound waves propagate and spread in space. It describes how the sound energy is distributed in different directions from a loudspeaker. Dispersion patterns determine the coverage area and the way sound is perceived at different listening positions. When a loudspeaker radiates sound, the dispersion pattern determines the spatial distribution of sound energy, including the angle and intensity of the sound in various directions. The dispersion pattern...

Imaging

Imaging refers to the ability of a speaker system to create a realistic and accurate soundstage, where the listener perceives the sound originating from specific locations within the listening environment. It is a crucial aspect of audio reproduction that aims to replicate the spatial qualities of the original sound source. Good imaging is essential for providing a sense of depth, width, and height to the audio presentation. When a speaker system has excellent imaging, it can...

Motor

The motor assembly of a loudspeaker driver is responsible for creating the magnetic field that interacts with the voice coil, allowing the driver to convert electrical signals into sound waves. The design of the motor assembly affects the driver's efficiency, power handling, and overall performance. While there can be various motor assembly configurations, the most common type is the "permanently magnetized motor." The motor assembly of an average loudspeaker driver...

Bandpass Enclosure

A bandpass enclosure is a type of loudspeaker or subwoofer enclosure that allows a specific range of frequencies to pass through and be radiated into the listening environment. It consists of two chambers, a sealed or ported front chamber, and a tuned ported rear chamber, with the driver mounted between them. The bandpass enclosure is designed to provide efficient and controlled output within a certain frequency band, resulting in a focused and powerful sound output....

Back Plate

The back plate (sometimes referred to as the bottom plate) is a stationary component of a driver’s motor assembly that works in conjunction with the voice coil and magnet to convert electrical signals into sound waves. Typically made from a ferromagnetic material (such as iron or steel), the back plate is mounted behind the voice coil and is usually a flat or slightly concave structure with a central opening through which the voice coil passes. The primary function of the...

Acoustic Lens

An acoustic lens refers to a device or structure designed to manipulate the direction, dispersion, or focusing of sound waves. The term is inspired by the concept of optical lenses used in optics to manipulate light. The primary purpose of an acoustic lens is to modify the propagation characteristics of sound waves, enabling control over their distribution and spatial behavior. Acoustic lenses can be implemented in various forms, including physical structures, signal processing...

Dome

A driver that utilizes a dome-shaped (convex) diaphragm is commonly referred to as a dome driver. This design is often used in tweeters and occasionally in midrange drivers. The dome diaphragm is typically made of materials like silk, fabric, or metal (aluminum, titanium, and beryllium are relatively common), and is attached to a voice coil at its center.

Advantages of Dome Drivers:

• Wide Dispersion: Dome drivers have the advantage of providing wide dispersion of

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