Breaking with modern conventions - a highly musical 2-way system using an 8" woofer

By Jon Hancock

This article will describe the fruits of my efforts to build a moderate sized speaker which might be moderately above average in performance for a basic two-way system. I desired a speaker like this both for my own use in secondary systems, and to fill a need for some friends, who desired fairly full range response (i.e., “it’s gotta have good bass”). Also, though I have access to a good wood shop, many potential DIY enthusiasts may not, so I hoped to use a modified...

IB- F.A.Q.
1)What's an IB?
For purposes of this forum, an Infinite Baffle is a alignment where the drivers are free-air mounted, in a space adjacent the listening room. They fire into the listening area through a common opening between the two areas. This can be the attic, basement, or any room with shares a common wall with the listening area.

2)Which space is best?
Any space that provides a mounting location for the baffle, offers adequate volume for the IB, and...

Suspension

The suspension refers to the mechanical system that provides support and control for the diaphragm (cone/dome) and voice coil within the driver's magnetic structure. The suspension is an important component that allows the diaphragm to move back and forth in response to the electrical audio signal while maintaining stability and linearity. The suspension system typically consists of two key components: the spider and the surround.

• Spider: The spider, also known as the "speaker

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Surround

In the context of loudspeaker drivers, the surround, also known as the "speaker surround" or "suspension surround," is a component that plays an important role in the driver's suspension system. The surround is typically a flexible ring or membrane that connects the outer edge of the loudspeaker diaphragm (cone/dome) to the driver's frame (basket). The primary function of the surround is to provide a compliant and flexible suspension for the diaphragm, allowing...

Spider

In the context of loudspeaker drivers, the spider refers to a component that plays an important role in the suspension system of the driver. The spider is an essential part of the driver's overall mechanical structure, helping to center and control the movement of the voice coil and diaphragm within the magnetic gap. The spider is typically located between the voice coil and the frame (basket) of the loudspeaker driver. It is made of a flexible material, such as cloth or treated...

Soundstage

Soundstage refers to the perceived spatial placement and localization of sound sources in a recording. It describes the three-dimensional presentation of audio, making it seem as if the sound is originating from specific locations within the listening environment, rather than coming directly from the loudspeakers. When a recording and playback system is capable of creating a convincing soundstage, listeners can experience a more immersive and realistic audio experience. The...

SINAD (Signal to Noise and Distortion ratio)

While not directly applicable to loudspeaker design, SINAD is a term in common use and is a valuable tool when comparing electronic equipment to match with your speakers. It can also be used when deciding what equipment you'd like to use for your measurement setup. SINAD stands for "Signal-to-Noise and Distortion ratio." It is a metric used to quantify the audio quality of electronic devices, particularly audio equipment like amplifiers...

Signal-to-Noise Ratio (SNR)

The signal-to-noise ratio (SNR) is an important parameter that helps evaluate the performance and quality of the audio output. In the context of audio, SNR refers specifically to the ratio of the desired audio signal (the sound produced by the loudspeaker driver) to the background noise generated by the speaker itself or the overall system.

The formula to calculate SNR in decibels is:

SNR (dB) = 10⋅log⁡₁₀(Power_Signal/Power_Noise)

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Sealed Enclosure

A sealed enclosure, also known as an acoustic suspension enclosure, is a type of loudspeaker cabinet design used in speaker systems. It is one of the most straightforward and commonly used enclosure designs in the audio industry. The primary purpose of a sealed enclosure is to provide a controlled environment for the loudspeaker driver to operate optimally. The basic principle is quite simple: the loudspeaker driver (usually a woofer or midwoofer) is mounted on a baffle...

Sensitivity

Sensitivity measures how effectively a loudspeaker converts electrical power (input signal) into acoustic power (sound output). Sensitivity is typically expressed in decibels (dB) and is measured at a specific distance from the loudspeaker driver with a standardized input power level of one watt (1W) or other defined power levels. The sensitivity rating indicates the sound pressure level (SPL) produced by the loudspeaker at that distance and power level. For example, a speaker...

Off-axis

"Off-axis" refers to any direction away from the central axis of a loudspeaker's radiation pattern. In other words, it describes the sound field and behavior of a loudspeaker when the listener is not directly positioned in front of the speaker at its primary listening axis. When a listener moves to the side, above, or below the central axis of the loudspeaker, they are in the off-axis listening position. Off-axis response is an essential consideration in loudspeaker...

Ribbon

A ribbon tweeter is a type of high-frequency transducer used in loudspeakers to reproduce the treble and upper midrange frequencies. It is called a "ribbon" tweeter because its diaphragm is typically a thin, narrow strip of metal foil or film that resembles a ribbon. The ribbon diaphragm is suspended in a magnetic field, and when an electrical current passes through it, it vibrates back and forth to produce sound. This design comes with several advantages:

• Lightweight

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Resonance

Resonance refers to a phenomenon where an object or system vibrates with a significantly increased amplitude at a specific frequency when exposed to an external force or energy. This frequency at which the object or system vibrates most strongly is known as the resonant frequency. In loudspeakers, resonances can occur in various components and aspects of the system:

• Diaphragm Resonance: The diaphragm of a loudspeaker driver (cone or dome) can have natural resonances due

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Rear Wave

The "rear wave" refers to the sound waves generated by the backside of the diaphragm of the loudspeaker driver. When the driver's voice coil moves back and forth in response to the electrical signal from the amplifier, it causes the diaphragm (cone or dome) to vibrate and produce sound waves both in front and behind the driver. The front wave is the sound that radiates forward and interacts directly with the listener, creating the desired sound output. However, the...

Reactance

Reactance refers to the component of impedance that arises due to the reactive elements in the driver's electrical circuit. Reactance is a complex impedance that includes both resistance and reactance, with reactance having both inductive and capacitive components. Understanding reactance is essential in loudspeaker design and analysis, as it affects the electrical and acoustic behavior of the driver.

There are two types of reactance commonly encountered in loudspeaker...