Construction

The high-tech design of an NlightN Flat Panel Speaker is exceedingly simple. No woofer, no tweeter, no crossover. Just a tiny magnet, a moving coil motor and a resign infused paper membrane mounted on an aluminum panel. The conventional splitting of the audio signal for the tweeter, mid-range and woofer is avoided.

In a conventional speaker, the signal from the amplifier energizes a magnetized voice coil connected to a diaphragm. The diaphragm moves in unison, causing the surrounding air to vibrate to recreate the original audio wave form as accurately as possible.

NlightN Flat Panel Speakers use a rigid panel, or "membrane," which serves as a diaphragm. The diaphragm is actuated by the tiny vibrations of five moving coil motors. The motors, which are attached to the panel, vibrate in microscopic motions, never exceeding 40 microns. The panel diaphragm, instead of moving in unison, responds with a series of bending waves in chaotic patters that cover the entire surface. This is the future of audio!

Conventional Speaker Development and Design

In the 1920s, two General Electric engineers proposed a theory to design an electric loudspeaker, which was described as a "direct-radiator loudspeaker with a small coil-driven mass-controlled diaphragm in a baffle with a broad midfrequency range of uniform response." This was the beginning of the conventional "cone" moving coil speaker, which soon replaced the mechanical "horn" of the original grammaphone record player.

This "cone" speaker design is based on a diaphragm that is positioned at the base of the horn and driven by a strong magnet. The entire diaphragm moves as a single unit and propels air at high velocity out of the front of the speaker. An electrodynamic "dome" tweeter also operates as a "pistonic" speaker.

Over the years, a great deal of audio research has been directed to overcoming the inherent problems of the "forward radiating" unipolar "direct radiator" speaker design. The design of a conventional cone speaker is always a compromise between frequency response (bass), efficiency (sound pressure level), and cabinet size.

Tradeoffs and Compromises in Conventional Cone Speaker Design

The cone speaker design is limited by the materials available to work with. The woofer is nothing more than a fragile paper cone that is pushed by a wound wire moving in the gap of a magnet whose magnetic field should be uniform but seldom is. The tweeter is usually a small device that is asked to reproduce the audio waves emitted by large musical instruments with massive radiating surfaces. To these challenges is added the difficult task of producing electronic crossovers that can separate the audio signals for the tweeter, midrange speaker and woofer.

To all of this is added the problem of speaker efficiency. Conventional cone speakers are notoriously inefficient, meaning that they produce a lot more heat than music. Because of this limitation, many conventional cone speakers are equipped with large drivers and heavy magnets, and are enclosed in big cabinets. Any improvements in efficiency are usually offset by the narrowing of frequency response. Speaker designers often wrestle with the problem of size versus performance. Bigger enclosures improve the bass response and volume, but increase the price of the speaker. Smaller speaker cabinets provide better dispersion and frequency response, but without the realism.

Speakers are designed to deliver acoustical output across a wide bandwidth. But when the radiated wavelength becomes smaller than the circumference of the diaphragm, the speaker's power output begins to fall. As a result, the bandwidth of a conventional cone only is limited to four or five octaves. This physical fact imposes a limitation on conventional speaker design, even if it were possible to produce the perfect pistonic radiator.

The NlightN Flat Panel Speaker design eliminates many of the deficiencies of the conventional cone speaker. In operation, it approximates the resonance patterns of the musical instruments producing the sound with its chaotic bending wave resonance. With its unmatched bandwidth, no crossover is needed, except for the very low frequencies where the hearing sensitivity is minimized. It does not have to contend with out of phase sound waves, such as those produced by the reciprocal motion of a pistonic diaphragm.

The New Transducer

A loudspeaker is a type of "transducer" in that it converts energy from one form into another. More specifically, it transforms electrical impulses into sound waves. The NlightN Flat Panel Speakers utilize the licensed technology that was developed by New Transducer, plc in the United Kingdom. This technology is referred to by the trade name of "NXT" Sound. (A "NXT" logo is affixed to each panel.)

The NlightN is a commercial grade speaker that is equipped with five “moving coil motor” exciters, each of which is positioned precisely so as to most effectively actuate the resonant modes of the panel. This advanced design is fully compatible with conventional amplifiers. In fact, the NlightN exciters actually reduce the load on the amplifier, as they are essentially resistive at the low and midrange frequencies. As frequency rises, the inductance of the moving coil motor becomes significant, the impedance coefficient increases, and the load becomes reactive. All of this is accomplished without combining low impedance with a high phase angle. The use of multiple exciters expands the bandwidth and sound pressure level of the NlightN panel to its full potential.

Panel Materials

The panel is structured with a variety of components which are fused together. A phenolic paper membrane is affixed to a honeycomb composite base, and this is attached to a metal chassis. The chassis consists of two plates: aluminum and Zintec Steel. The panel is supported by a wooden frame, crafted from medium density fiberboard.

Phenolic paper is a resin-infused "thermoplastic" medium that exhibits strength and rigidity. It has good electrical insulation properties. This material is used in a very wide range of electrical installations and in equipment where rigid electrical insulation is required. It is ideal for high voltage applications, and in conditions of varying humidity where electrical stability is an important consideration.

Thermoplastic describes the characteristics of synthetic plastic or resin, which becomes soft when heated and rehardens on cooling without appreciable change of properties

Zintec is the trade name for the cold rolled sheet that has been electrolytically coated with a thin layer of zinc. It is produced at steel thicknesses of 0.4 to 2.0mm and contains a thickness of zinc from 1.0 to 1.75 microns. Zintec is used in the manufacture of sheet steel pressed products, such as washing machines, air conditioning plants, and car bodies.

Electrical Protection

The NlightN Flat Panel Speaker is equipped with an integral 100 Hz High Pass Filter. It also has an internal self-resetting fuse, and a chassis mounted cartridge fuse or circuit breaker. When power limits are initially exceeded, the internal fuse will cause a momentary reduction in power. If the cause is not remedied, then the fuse or circuit breaker will cut the power. The circuit breaker displays a light when it has been tripped.

It is exceedingly important to select a properly sized amplifier to power the NlightN Flat Panel Speakers. The amplifier should not exceed 150 watts per channel. Use of an higher power amplifier is likely to overdrive the speaker and that may void the limited warranty.

A Frame Instead of a Cabinet

NlightN panels are designed to emit sound from both the front and the rear, with the two sides working in phase with each other. With this mode of operation, the NlightN can be supported by a simple frame. There is no need for a cabinet. All conventional cone speakers are configured with an enclosure to control the out-of-phase sound emitted by the reciprocal movement of the diaphragm.

The fact that the NlightN Flat Panel Speaker does not behave in a directional manner means that it can be hung in a room and act effectively as two speakers radiating in two different directions. In contrast to the uniform, circular sound field generated by the NlightN Speaker design, a conventional cone speaker, because of its need for an enclosure, can only produce a semi-circular pattern of sound waves.

Production Facilities

The NlightN Flat Panel Speaker is produced by Carlsbro Electronics, Ltd in Nottinghamshire, United Kingdom. Carlsbro is a world renown audio company made famous by its guitar amplifiers, which have been used by numerous major rock bands around the world. It has been an industry pioneer in introducing well conceived and thoroughly tested products since its inception in 1961.

Links

Carlsbro Electronics, Ltd. Homepage

About Carlsbro Electronics Ltd.

The History of Carlsbro Electronics, Ltd.

NlightN Revolutionary Flat Panel Speaker Page

NXT Press Release: NlightN Flat Panel Speakers