Full-range speaker

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Cross-section of a full-range loudspeaker driver using a whizzer cone design. FullRangeSpk.svg
Cross-section of a full-range loudspeaker driver using a whizzer cone design.
Fostex FE206e (modified) full range drive unit using a whizzer cone. Fostex FE206e (modified) full-range drive unit loudspeaker, using a whizzer cone.jpg
Fostex FE206e (modified) full range drive unit using a whizzer cone.
Goodmans Axiette, one of the first single-cone full-range drivers. Goodmans Axiette 101 a.png
Goodmans Axiette, one of the first single-cone full-range drivers.

A full-range loudspeaker drive unit is defined as a driver which reproduces as much of the audible frequency range as possible, within the limitations imposed by the physical constraints of a specific design. The frequency range of these drivers is maximized through the use of a whizzer cone and other means. Most single driver systems, such as those in radios, or small computer speaker designs, cannot reproduce all of the audible frequencies or the entire audible audio range (i.e., sound within the range of human hearing).

Contents

Typical designs

Typically, a full-range drive unit consists of a single driver element, or voice coil , used to move and control a diaphragm. Often the cone structure includes optimizations to enhance high-frequency performance. For example, a small low-mass horn or whizzer cone can be mounted where the voice coil and diaphragm meet, thereby increasing the output at high frequencies. The shape and materials used in the cone and whizzer are highly optimized. Manufacturers strive to optimize the materials, design, and construction of each component to achieve optimal performance and audio fidelity. Advanced technologies such as neodymium magnets, voice coil cooling systems, and wave guides further enhance the speakers’ capabilities, ensuring accurate sound reproduction and minimizing distortion. [1]

Another arrangement uses a radiating dome in place of the usual dust-cap; it is acoustically active. In most speaker drivers such dust-caps are constructed so as to be relatively acoustically inert. Sometimes the dust-cap takes the form of a small conical shape, claimed to improve dispersion at higher frequencies. Yet other designs simply modify the diaphragm and dome/whizzer materials instead of compliantly coupling the diaphragm to achieve full-range operation.[ citation needed ]

In some designs, the main diaphragm may be coupled to the voice coil using a compliant bond such that high frequency vibrations are not transmitted into it, but instead move the whizzer cone. The technique of using a compliantly coupled (or modified) diaphragm for the low frequencies and auxiliary whizzer or modified dust-cap (dome) for the high frequency response of a speaker is a mechanical implementation of an audio crossover.

Since the requirements of a full-range driver include both good low and high frequency response (which are contradictory in terms of physical construction), a full-range driver is usually limited to covering the audio spectrum above perhaps 100 Hz—leaving lower frequencies to be handled / augmented by a separate sub woofer or by a special cabinet design for low frequency reinforcement. These requirements usually mean that the full-range must have good sensitivity (for lower frequencies) with a light voice coil (for high frequencies) these speakers commonly use a larger or more powerful magnet than usual, which improves sensitivity and thus lowers the power requirement at low frequencies as well as allowing a lighter voice coil. In addition, many have limited maximum excursions, requiring special enclosures which do not require large excursions at low frequencies for reasonable low end output.

There are rare exceptions that use multiple elements to drive a common diaphragm, but these should not be confused with coaxial speakers that use separate and concentrically aligned elements to achieve the desired range of reproduction, and are not, strictly, classified as full-range drivers.

Full-range drivers are seen in applications ranging from televisions and computer speakers, to hi-fi speaker systems. The performance of the driver is substantially affected by their enclosure, and enclosures vary from mundane beige plastic boxes, at the low end of the scale, to large horn loaded enclosures with spectacular audio performance.

Atypical designs

A German company, Manger, produces an unusual full-range driver in the form of a differentially flexing flat diaphragm driver, about eight inches in diameter. Manger claims performance, both maximum level and extended low frequency response, which is rather better than traditional full-range drivers.

Another unusual full-range driver design is the Walsh driver, popularized in Ohm hi-fi speaker systems, where they reproduced almost the entire audible range of frequencies. Early Walsh units were large and expensive. These drivers used a single cone made with paper at the base, reproducing low frequencies, aluminium in the middle area, and titanium at the neck zone, to produce high frequencies. Slits in the paper area of the cone, covered with silicone damping, together with internal foam pads provided mechanisms for tailoring the frequency response to be as flat as possible. Loudspeakers using the Walsh driver are still in production, though they have adopted a tweeter so no longer qualify as full-range drivers.

A variation on the Walsh driver from a company called German Physiks, based in Maintal near Frankfurt, is available in two forms. One uses a cone made from titanium foil 0.025 mm thick and an improved version that uses 0.15 mm thick carbon fibre. These are used in their range of audiophile loudspeakers. [2]

Large electrostatic loudspeakers may be considered as full-range speakers in the sense that they are capable of reproducing most of the audio frequency band.

Applications

Full-range drive units may be found in applications ranging from inexpensive multimedia loudspeakers to more costly esoteric systems, the latter often using large transmission line or horn loaded enclosures to increase low frequency output. There is an active hobbyist speaker construction group on the Web focusing on full-range drivers and enclosures for them.

Since every electronic, mechanical or acoustical component in reproduction chain will, regardless of purpose, degrade fine detail, the fewer components between the amplifier terminals and the listening room, the better. This includes conventional "mid-kilohertz" crossovers, which, in addition, destroy the natural integrity of the harmonic structure by the abrupt severance of the harmonics from the fundamental frequencies. These problems are avoided with the single cone moving coil driver which is to loudspeakers as the wheel is to the car.

Edward James Jordan, interviewed by TNT-Audio [3]

Commercial applications

Spherical Speaker with single driver Mo-sound-ballspeaker-porzellanmanufaktur augarten.jpg
Spherical Speaker with single driver

A large number of full-range drive units are used in commercial sound systems, which may employ a number of 200 mm (8") full-range drivers, mounted into suspended ceilings or small 'back-box' enclosures. These convey background music and announcements to workers and visitors in retail stores, and public spaces. While these drivers are classed as 'full-range', it may be more accurate to term them 'wide-range' drivers, since their output abilities rarely extend to the extremes of the frequency range. Several manufacturers build small (typically 115 mm (4.5")) diameter full-range drivers into miniature enclosures, and many of these include 25 or 70-volt line transformers, for use on commercial sound systems employing long speaker cables. Some full-range speaker systems are designed with limited-range drivers, and must be used with equalizers to flatten and extend their frequency response, while others achieve acceptable response without electronic assistance. There are full-range speaker systems using up to 15" single drivers. [4]

Critical reaction

Critics of full range drivers cite their inability to reproduce the full range of audio frequencies at similar amplitudes, leading to inaccurate reproduction of the audio signal sent to it. Reproducing multiple frequencies with the same diaphragm can increase intermodulation distortion, a non-linear effect that occurs when one surface attempts to reproduce both frequencies simultaneously. The audible severity of modest intermodulation distortion is not well established. The result is a degree of "frequency mixing", albeit at a relatively low level. A full range driver may have reduced output at both ends of its frequency range, or a more severely limited frequency response, resulting in a more compromised sound. Partisans of full-range loudspeakers claim superior phase coherence, while some critics describe them as midrange speakers working at or beyond their limits. Some full range drivers have been developed using 12" and 15" drivers, e.g. Audio Nirvana, and have overcome the bass limitations of smaller drivers using bass reflex cabinets. Also, as most adults cannot hear above 15 kHz the lack of high end frequency is generally not an issue with modern well designed full range drivers.

See also

Related Research Articles

<span class="mw-page-title-main">Subwoofer</span> Loudspeaker for low-pitched audio frequencies

A subwoofer is a loudspeaker designed to reproduce low-pitched audio frequencies, known as bass and sub-bass, that are lower in frequency than those which can be (optimally) generated by a woofer. The typical frequency range that is covered by a subwoofer is about 20–200 Hz for consumer products, below 100 Hz for professional live sound, and below 80 Hz in THX-certified systems. Thus, one or more subwoofers are important for high-quality sound reproduction as they are responsible for the lowest two to three octaves of the ten octaves that are audible. This very low-frequency (VLF) range reproduces the natural fundamental tones of the bass drum, electric bass, double bass, grand piano, contrabassoon, tuba, in addition to thunder, gunshots, explosions, etc.

<span class="mw-page-title-main">Loudspeaker</span> Converts an electrical audio signal into a corresponding sound

A loudspeaker is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A speaker system, also often simply referred to as a speaker or loudspeaker, comprises one or more such speaker drivers, an enclosure, and electrical connections possibly including a crossover network. The speaker driver can be viewed as a linear motor attached to a diaphragm which couples that motor's movement to motion of air, that is, sound. An audio signal, typically from a microphone, recording, or radio broadcast, is amplified electronically to a power level capable of driving that motor in order to reproduce the sound corresponding to the original unamplified electronic signal. This is thus the opposite function to the microphone; indeed the dynamic speaker driver, by far the most common type, is a linear motor in the same basic configuration as the dynamic microphone which uses such a motor in reverse, as a generator.

<span class="mw-page-title-main">Audio crossover</span> Electronic filter circuitry used in loudspeakers

Audio crossovers are a type of electronic filter circuitry that splits an audio signal into two or more frequency ranges, so that the signals can be sent to loudspeaker drivers that are designed to operate within different frequency ranges. The crossover filters can be either active or passive. They are often described as two-way or three-way, which indicate, respectively, that the crossover splits a given signal into two frequency ranges or three frequency ranges. Crossovers are used in loudspeaker cabinets, power amplifiers in consumer electronics and pro audio and musical instrument amplifier products. For the latter two markets, crossovers are used in bass amplifiers, keyboard amplifiers, bass and keyboard speaker enclosures and sound reinforcement system equipment.

<span class="mw-page-title-main">Tweeter</span> Type of loudspeaker

A tweeter or treble speaker is a special type of loudspeaker that is designed to produce high audio frequencies, typically up to 100 kHz. The name is derived from the high pitched sounds made by some birds (tweets), especially in contrast to the low woofs made by many dogs, after which low-frequency drivers are named (woofers).

<span class="mw-page-title-main">Mid-range speaker</span> Loudspeaker driver

A mid-range speaker is a loudspeaker driver that reproduces sound in the frequency range from 250 to 2000 Hz.

A woofer or bass speaker is a technical term for a loudspeaker driver designed to produce low frequency sounds, typically from 20 Hz up to a few hundred Hz. The name is from the onomatopoeic English word for a dog's deep bark, "woof". The most common design for a woofer is the electrodynamic driver, which typically uses a stiff paper cone, driven by a voice coil surrounded by a magnetic field.

<span class="mw-page-title-main">Electrostatic loudspeaker</span> Sound playback device

An electrostatic loudspeaker (ESL) is a loudspeaker design in which sound is generated by the force exerted on a membrane suspended in an electrostatic field.

<span class="mw-page-title-main">Damping factor</span> Ratio of impedance of a loudspeaker

In an audio system, the damping factor is defined as the ratio of the rated impedance of the loudspeaker to the source impedance of the power amplifier. It was originally proposed in 1941. Only the magnitude of the loudspeaker impedance is used, and the power amplifier output impedance is assumed to be totally resistive.

<span class="mw-page-title-main">Horn loudspeaker</span> Loudspeaker using an acoustic horn

A horn loudspeaker is a loudspeaker or loudspeaker element which uses an acoustic horn to increase the overall efficiency of the driving element(s). A common form (right) consists of a compression driver which produces sound waves with a small metal diaphragm vibrated by an electromagnet, attached to a horn, a flaring duct to conduct the sound waves to the open air. Another type is a woofer driver mounted in a loudspeaker enclosure which is divided by internal partitions to form a zigzag flaring duct which functions as a horn; this type is called a folded horn speaker. The horn serves to improve the coupling efficiency between the speaker driver and the air. The horn can be thought of as an "acoustic transformer" that provides impedance matching between the relatively dense diaphragm material and the less-dense air. The result is greater acoustic output power from a given driver.

Thiele/Small parameters are a set of electromechanical parameters that define the specified low frequency performance of a loudspeaker driver. These parameters are published in specification sheets by driver manufacturers so that designers have a guide in selecting off-the-shelf drivers for loudspeaker designs. Using these parameters, a loudspeaker designer may simulate the position, velocity and acceleration of the diaphragm, the input impedance and the sound output of a system comprising a loudspeaker and enclosure. Many of the parameters are strictly defined only at the resonant frequency, but the approach is generally applicable in the frequency range where the diaphragm motion is largely pistonic, i.e., when the entire cone moves in and out as a unit without cone breakup.

<span class="mw-page-title-main">Bass reflex</span> Type of loudspeaker enclosure with improved bass performance

A bass reflex system is a type of loudspeaker enclosure that uses a port (hole) or vent cut into the cabinet and a section of tubing or pipe affixed to the port. This port enables the sound from the rear side of the diaphragm to increase the efficiency of the system at low frequencies as compared to a typical sealed- or closed-box loudspeaker or an infinite baffle mounting.

The chief electrical characteristic of a dynamic loudspeaker's driver is its electrical impedance as a function of frequency. It can be visualized by plotting it as a graph, called the impedance curve.

<span class="mw-page-title-main">Acoustic Research</span>

Acoustic Research was a Cambridge, Massachusetts-based company that manufactured high-end audio equipment. The brand is now owned by VOXX. Acoustic Research was known for the AR-3 series of speaker systems, which used the 12 in (300 mm) acoustic suspension woofer of the AR-1 with newly designed dome mid-range speaker and high-frequency drivers. AR's line of acoustic suspension speakers were the first loudspeakers with relatively flat response, extended bass, wide dispersion, small size, and reasonable cost. The AR Turntable remains a highly sought vinyl record player.

<span class="mw-page-title-main">Loudspeaker enclosure</span> Acoustical component

A loudspeaker enclosure or loudspeaker cabinet is an enclosure in which speaker drivers and associated electronic hardware, such as crossover circuits and, in some cases, power amplifiers, are mounted. Enclosures may range in design from simple, homemade DIY rectangular particleboard boxes to very complex, expensive computer-designed hi-fi cabinets that incorporate composite materials, internal baffles, horns, bass reflex ports and acoustic insulation. Loudspeaker enclosures range in size from small "bookshelf" speaker cabinets with 4-inch (10 cm) woofers and small tweeters designed for listening to music with a hi-fi system in a private home to huge, heavy subwoofer enclosures with multiple 18-inch (46 cm) or even 21-inch (53 cm) speakers in huge enclosures which are designed for use in stadium concert sound reinforcement systems for rock music concerts.

The Air Motion Transformer (AMT) is a type of electroacoustic transducer. Invented by Oskar Heil (1908–1994), it operates on a different transduction principle from other loudspeaker designs, such as moving coil, planar magnetic or electrostatically-driven loudspeakers, and should not be confused with planar or true ribbon loudspeakers. In contrast to a planar ribbon loudspeaker, the diaphragm of the AMT is of pleated shape similar to a bellows. The AMT moves air laterally in a perpendicular motion using a metal-etched folded sheet made of polyethylene terephthalate (PET) film. The circuit path embossed on the PET membrane, acts as the voice coil unit. The diaphragm is then housed between 4 stacks of steel pole-plate pieces positioned at 45° within a high-intensity, quadratic, opposing magnetic field. The air motion transformer with its sheet film equally exposed at 180° behaves as a dipole speaker, exciting front and rear sonic waves simultaneously.

<span class="mw-page-title-main">Plasma speaker</span> Loudspeaker

Plasma speakers or ionophones are a form of loudspeaker which varies air pressure via an electrical plasma instead of a solid diaphragm. The plasma arc heats the surrounding air causing it to expand. Varying the electrical signal that drives the plasma and connected to the output of an audio amplifier, the plasma size varies which in turn varies the expansion of the surrounding air creating sound waves.

<span class="mw-page-title-main">Acoustic suspension</span> Loudspeaker cabinet design

Acoustic suspension is a loudspeaker cabinet design that uses one or more loudspeaker drivers mounted in a sealed box. Acoustic suspension systems reduce bass distortion which can be caused by stiff suspensions required on drivers used for open cabinet designs.

wOOx Technology is a brand created by Philips to identify loudspeaker systems that employ passive radiator technology along with active equalisation to maximize the output of the passive diaphragm. wOOx Technology optimizes the active bass driver, the passive bass radiator, and the active equalisation curve to obtain maximum low-frequency reproduction in a relatively compact configuration.

<span class="mw-page-title-main">Moving iron speaker</span>

The moving iron speaker was the earliest type of electric loudspeaker. They are still used today in some miniature speakers where small size and low cost are more important than sound quality. A moving iron speaker consists of a ferrous-metal diaphragm or reed, a permanent magnet and a coil of insulated wire. The coil is wound around the permanent magnet to form a solenoid. When an audio signal is applied to the coil, the strength of the magnetic field varies, and the springy diaphragm or reed moves in response to the varying force on it. The moving iron loudspeaker Bell telephone receiver was of this form. Large units had a paper cone attached to a ferrous metal reed.

<span class="mw-page-title-main">Electrodynamic speaker driver</span> Individual transducer that converts an electrical audio signal to sound waves

An electrodynamic speaker driver, often called simply a speaker driver when the type is implicit, is an individual transducer that converts an electrical audio signal to sound waves. While the term is sometimes used interchangeably with the term speaker (loudspeaker), it is usually applied to specialized transducers that reproduce only a portion of the audible frequency range. For high fidelity reproduction of sound, multiple loudspeakers are often mounted in the same enclosure, each reproducing a different part of the audible frequency range. In this case the individual speakers are referred to as drivers and the entire unit is called a loudspeaker. Drivers made for reproducing high audio frequencies are called tweeters, those for middle frequencies are called mid-range drivers and those for low frequencies are called woofers, while those for very low bass range are subwoofers. Less common types of drivers are supertweeters and rotary woofers.

References

  1. "What Are Full Range Speakers and How Do They Work [2023]". AudioFavorite.
  2. https://www.german-physiks.com/technology-ddd-driver-development [ bare URL ]
  3. "Interview with Ted Jordan, of E.J.Jordan Designs". TNT-Audio. 2000. Archived from the original on 2008-02-05. Retrieved 2009-01-23.
  4. "About Our Product". R2R Audio. After many years of research and development R2R Audio introduced in 2010 the flagship product – 15 inch Full Range loudspeaker active system.