Exploring Common DIY Terminology - Impulse Response

Impulse Response

An impulse response is a graphical representation of a loudspeaker's response to an ideal impulse signal. The impulse response is essentially the loudspeaker's reaction to a sharp and short burst of energy. It is a powerful tool for loudspeaker designers to assess the speaker's time-domain performance and identify various characteristics of its sound reproduction. Creating an impulse response graph for a loudspeaker requires specialized equipment and software for accurate...

Open Baffle (OB)

The open baffle (OB) technique is a loudspeaker design approach that involves mounting the speaker drivers on a flat, baffle-like panel without any enclosure or cabinet behind them. When a traditional loudspeaker is mounted in a sealed or ported enclosure, the rear wave of the driver is trapped within the enclosure, leading to pressure build-up and potential reflections. In the open baffle design, the rear wave is allowed to radiate freely into the surrounding space,...

Power Handling

Power handling refers to the maximum amount of electrical power a loudspeaker can handle without suffering damage or performance degradation. It is a manufacturer specification that indicates the speaker's ability to handle different power levels and is typically measured in watts (W). The factors that determine power handling are varied:

• Voice Coil Size and Material: The size and material of the voice coil play a significant role in power handling. Larger voice coils

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Planar Magnetic Transducers

A planar magnetic transducer, also known as a planar driver, is a type of loudspeaker driver that uses a thin and lightweight diaphragm with an embedded conductive coil to produce sound. It operates based on the principles of magnetic induction. A planar driver consists of the below:

• Diaphragm: The diaphragm of a planar magnetic driver is a thin, flat, and often rectangular or circular membrane made from a lightweight material such as mylar or a thin metal

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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...

Power Compression

Power compression is a phenomenon that occurs when the voice coil and other components of a loudspeaker driver heat up due to increased power input. As the voice coil temperature rises, its resistance also increases, leading to a decrease in the electrical power converted into acoustic output. This reduction in acoustic output for a given electrical power input is known as power compression. The concept of power compression is essential to understand because it can...

Nominal Impedance

Nominal impedance is a manufacturer specification commonly used to describe the average or approximate electrical impedance of a loudspeaker or individual driver. It is usually represented by a single value, such as 4 ohms or 8 ohms. For consumer audio, the nominal impedance indicates the most difficult average load a loudspeaker presents to an amplifier under normal operating conditions and is used to match the speaker to the amplifier's output impedance. For designing...

Overhung Voice Coil

An overhung voice coil is a type of loudspeaker driver design where the winding height of the voice coil is longer than the height of the magnetic gap in which it operates. In this design, the coil extends beyond the magnetic gap, giving it a longer excursion capability than a standard driver.

Pros of Overhung Voice Coils:

• Greater Excursion Capability: Overhung voice coils have a longer excursion range, allowing them to move the speaker cone farther

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Underhung Voice Coil

An underhung driver is a type of design where the voice coil's winding height is shorter than the height of the magnetic gap in which it operates. In other words, the coil does not extend fully through the magnetic gap, and it remains "underhung" within the magnetic structure. In a standard loudspeaker driver, the voice coil is wound on a cylindrical former and moves within the magnetic gap, which is a cylindrical space between the pole piece and the magnetic...

Neodymium Magnet

A neodymium magnet is a type of permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd₂Fe₁₄B tetragonal crystalline structure. It is one of the strongest and most powerful magnets available, offering high magnetic strength in a compact and lightweight form. In loudspeaker design, neodymium magnets are commonly used to create powerful and efficient magnetic fields within the speaker's motor structure. The motor structure is a critical component...

Polarity

In loudspeaker design, polarity refers to the orientation of the electrical signals that drive the various drivers (such as woofers, tweeters, and midrange drivers) within the loudspeaker system. The polarity of a driver determines whether the cone or diaphragm of the driver moves inward (towards the magnet) or outward (away from the magnet) when a positive voltage is applied to the driver's positive terminal. Correct polarity is essential for achieving proper phase alignment...

Port

A loudspeaker port, also known as a bass reflex port, vented enclosure, or ported enclosure, is a design feature used in loudspeakers and subwoofers to improve their low-frequency performance. It operates based on the principles of Helmholtz resonance. In a typical loudspeaker, when the speaker cone moves back and forth, it generates both front and rear sound waves. The front sound wave radiates into the room and produces the desired sound output, while the rear sound wave travels...

Pole Piece

The pole piece is a crucial component of the magnetic structure of a driver, especially in dynamic drivers (also known as moving-coil drivers). It is located at the center of the magnet assembly and plays a vital role in the driver's performance by focusing and guiding the magnetic flux. The pole piece typically consists of a cylindrical or conical metal structure that surrounds the center pole of the magnet. It creates a magnetic field that interacts with the voice coil,...

Pistonic Behavior

Pistonic behavior in a loudspeaker refers to the ideal movement of the driver's diaphragm, where it moves in a piston-like manner. In other words, when the speaker reproduces sound, its diaphragm moves uniformly and maintains a constant relationship between the applied input signal and the resulting sound output. This behavior is crucial for accurate and faithful sound reproduction.

Characteristics of Pistonic Behavior:

• Linear Motion: In pistonic behavior,

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Phase Plug

A phase plug is a stationary structure placed at the center of the loudspeaker driver's diaphragm, just in front of the voice coil. It is typically a cylindrical or conical-shaped object made of materials like plastic, metal, or wood. The phase plug's design may vary depending on the specific driver and its intended application. Its primary purpose is to improve the driver's performance by addressing issues related to phase cancellation and dispersion. The function of the...