fgd audio visual research

8/8/2019 Fgd Audio Visual Research

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Loudspeaker Driver

Diaphram Driver Components

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Audio-Visual Systems:

Loudspeakers

A loudspeaker (or speaker) is an electro-acoustic transducer that converts an electrical signalinto sound. The speaker moves in accordance withthe variations of an electrical signal and causes soundwaves to propagate through a medium such as air or

water.Individual drivers are used to reproduce different

frequency ranges. The drivers are named subwoofers(for very low frequencies); woofers (low frequencies);mid-range speakers (middle frequencies); tweeters(high frequencies); and sometimes supertweeters, op-timized for the highest audible frequencies.

When multiple drivers are used in a system,a lter network, called a crossover, separates theincoming signal into different frequency ranges androutes them to the appropriate driver. A loudspeakersystem with n separate frequency bands is describedas n-way speakers: a two-way system will have awoofer and a tweeter; a three-way system employs a

woofer, a mid-range, and a tweeter.

CH.09 CH.08 CH.07 CH.06 CH.05 CH.04 CH.03 CH.02 CH.01


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Passive Crossover

Active Crossover

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Loudspeakers

CrossoversUsed in multi-driver speaker systems, the

crossover is a subsystem that separates the input sig-nal into different frequency ranges suited to each driv-er. The drivers receive only the power in their usable

frequency range (the range they were designed for),thereby reducing distortion in the drivers and interfer-ence between them.

Passive crossover circuits need no externalpower beyond the audio signal itself, but do causeoverall signal loss and a signicant reduction in damp-ing factor between the voice coil and the crossover.

An active crossover is an electroniclter circuitthat divides the signal into individual frequency bandsbefore power amplication, thus requiring at least onepower amplier for each bandpass.



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3-way Horn Loudspeaker

Piezo Tweeter Construction

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Driver Designs

Horn loudspeakers are the oldest form of loud-speaker system. The use of horns as voice-amplifyingmegaphones dates at least to the 17th century, andhorns were used in mechanical gramophones as earlyas 1857. Horn loudspeakers use a shaped waveguide

in front of or behind the driver to increase the directivityof the loudspeaker and to transform a small diameter,high pressure condition at the driver cone surface toa large diameter, low pressure condition at the mouthof the horn. This increases the sensitivity of the loud-speaker and focuses the sound over a narrower area.The size of the throat, mouth, the length of the horn,

as well as the area expansion rate along it must becarefully chosen to match the drive to properly providethis transforming function over a range of frequencies.The length and cross-sectional mouth area required tocreate a bass or sub-bass horn require a horn manyfeet long.

Piezoelectricity was discovered by Jacque

and Pierre Curie in the late 1880s. They found thatcertain natural crystals generate an electriceld underthe inuence of a mechanical force. They named thephenomenon piezoelectricity, from the Greek meaningpressure electricity.

Piezoelectric speakers are frequently usedas beepers in watches, and are sometimes used astweeters in less-expensive speaker systems, suchas computer speakers and portable radios. They areresistant to overloads which would normally destroymost high frequency drivers, and they can be usedwithout a crossover due to their electrical properties.


CH 01 CH 02 CH 03 CH 04 CH 05 CH 06 CH 07 CH 08 CH 09


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Ribbon Speaker

Distributed Mode Loudspeaker

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Driver Designs

Magnetic Ribbon DriverThe mechanics behind a planar magnetic ribbon

is straight forward. A thin membrane, with an etchedcircuit on it, is directly and uniformly driven betweentwo opposing series of magnets. There is no voice coil

attached to the edge. An electromagnetic force actson the conductor and is evenly distributed over the en-tire diaphragm surface. This eliminates the tendencyto generate distributed resonance vibrations.

Flat Panel LoudspeakersThere have been many attempts to reduce

the size of speaker systems, or alternatively to makethem less obvious. One such attempt was the devel-opment of voice coils mounted toat panels to act assound sources. There are two related problems withat panel techniques: rst, a at panel is necessarilymore exible than a cone shape in the same material,and therefore will move as a single unit even less, and

second, resonances in the panel are difcult to con-trol, leading to considerable distortions.

Distributed Mode LoudspeakersA newer implementation of theat panel speak-

er system involves an intentionallyexible panel andan exciter, mounted off-center and located so as toexcite the panel to vibrate with minimal resonances.Speakers using such techniques can reproducesound with a wide directivity pattern (paradoxicallysomewhat like a point source)[citation needed] andhave been used in some computer speaker designsand bookshelf loudspeakers.




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Driver Designs

Bending wave transducers use a diaphragmthat is intentionallyexible. The rigidity of the materialincreases from the center to the outside. Short wave-lengths radiate primarily from the inner area, while lon-ger waves reach the edge of the speaker. To prevent

reections from the outside back into the center, longwaves are absorbed by a surrounding damper. Suchtransducers can cover a wide frequency range (80 Hzto 35,000 Hz) and have been promoted as being closeto an ideal point sound source.[47] This uncommonapproach is being taken by only a very few manufac-turers, in very different arrangements. Bending Wave diagram

Nine Layer Wooden MenbraneGoebel High End Modul Wall

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Referenece by KEF

Crossover Board

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Loudspeakers Types

Uni-QKEFs latest Uni-Q driver array is the most

natural-sounding yet. The tweeter at the centre of themidrange cone now has a vented three-magnet motorsystem and a unique new braced dome, creating a

perfectly time-aligned point source whose directivity isoptimised by the reproled cone. As a result, disper-sion is wider than ever. Power response is more uni-form. Multi-channel imaging is even more stable - andstunningly realistic.

CrossoverThe Reference Series crossovers are computer

modelled to optimise driver integration and responseaccuracy, and then ne-tuned by ear to ensure natural-ness and a musically rewarding listening experience.

Separate circuit boards are used wherever possiblefor the different frequency bands, with all componentscarefully laid out to minimise electro-magnetic interac-tions, and all boards are mechanically decoupled toisolate them from cabinet vibration. The quality of thesignal path is maintained by taking advantage of theminimal losses in polypropylene capacitors and thelinearity of air-cored inductors and the internal cablingis chosen for its accurate, neutral sonic character.




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Faraday Rings

Cabinet

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Loudspeaker Types

Faraday RingsKEF engineers have succeeded in greatly re-

ducing the distortions that affect moving coil driveunits by adding twin, balanced, Faraday rings aboveand below the voice coil. The negative effects caused

by ux modulation and the variation of coil inductancewith position are virtually eliminated by these carefullydesigned, low impedance shorted turns.By gener-ating a magnetic eld that cancels the unwanted eld from the voice coil, this innovation reduc-es harmonic distortion by as much as ten times (20dB). Extending the benets still further, the physi-

cal prescence of the metal rings aids heat dissipationover the whole length of the voice coil, thereby improv-ing the dynamic performance and power handling.

CabinetPrecision engineered to eliminate every un-

wanted vibration, Reference Series cabinets are works

of art in themselves. Massive internal bracing tailorsthe volume of each enclosure to the exact parametersof its drive unit. Extensive mechanical and acousticdamping, together with independent driver loadingand KEFs decoupling techniques, creates inert en-closures that eradicate any vestigial panel resonance,standing waves, stray reections or box colourations.



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Bose Wave music system

Waveguide Speaker Technology

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Audio Systems for the Home

The acclaimed Wave music system still setsthe standard for quality audio and ease of use amongone-piece, table top radios and bookshelf stereos. Itsaward-winning design adds a touch of distinction toalmost any room. Its no surprise so many people use

it as their main home entertainment system for musiclistening.

Waveguide TechnologyTwo 26 folded waveguides are precisely tuned

to amplify the output from the transducers (speakers)to reproduce lifelike sound from a small enclosure.



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B&K multiroom distribution bus

Niles Integrated Control

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Audio Systems for the Home

* An integration of a multi-room stereo audiodistribution Bus with twelve compact and efcient 60Wpower ampliers.

* Level Control - Local individual level controlof each amplier channel. May also be used to equally

attenuate the level for both amplier pairs.* Dip Switch Conguration - Used to con-

gure the On / Standby / Sense state of the unit, theBus audio and trigger distribution and Mono / Stereoconguration of the audio pairs.

* Bus Control and Muting - Allowing for singleswitching of the amplier audio sense on/off feature

and audio signal on any pair of amplier channels withthe Bus Switch enabled.* Mono Usage - Ability to have up to twelve

output channels that may be in mono.

The Contacts touchscreen brings a higher levelof control to home entertainment. The colorful screendisplays menus, guides, favorite channel listsevery-thing you need for todays digital entertainment. Avail-able in a wide range of colors and customnishes toblend with any dcor. When you Experience Intelli-Control ICS, youre a step above the others.



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Kaleidescape 1U Server

Canton Pro House Wa100

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Audio-Video Systems for the Home

The Kaleidescape 1U Server provides ultra-re-liable storage for your favorite movies and music. Likeall Kaleidescape servers, its able to continue runningeven after a drive failure while it continues to safelystore your valuable entertainment content.

As your collection grows, you can add addi-tional Kaleidescape Disk Cartridges to increase stor-age capacity for your movies and music. A single 1UServer can store up to 900 DVDs or 150 Blu-ray Discs.Multiple servers can be clustered in a single systemto store thousands of movies and albums as a single

collection.

Wireless Audio SystemWith its enormous reach of radio range WA 100

every desired room and creates music in your wholehouse. Here up to three WA 100 networks in parallel.

Other audio sources are not necessary.



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Sony 3D Television

PowerLite Pro Cinema projecto

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research sub-topic

The evolution will be televised. Soon you canexperience movies, TV, sports and video games instunning high-denition 3D. Breakthrough 3D technol-ogy and Sonys 3D

Active Glasses deliver a visceral sensation with

overwhelming depthand the effects are staggering.You dont just watch it, you live it.

The Epson PowerLite Pro Cinema 9500UBcreates cinematic adventures unlike any other with acontrast ratio up to 200,000:1, unprecedented in itsclass, innovative Super-resolution technology andpowerful widescreen performance. Epsons exclusive

Vertical Alignment (VA) LCD technology ensures deepblacks and extraordinary detail, putting you right in themiddle of where the action is. And, with its anamor-phic mode, the Pro Cinema 9500UB makes it easy toenjoy widescreen 2.35:1 movies and more. Whateveryou choose to view, setup is easy with innovative colormanagement features and ISF calibration, which al-lows you to customize colors for any environment.



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Soundproofing solutions.

Anechoic Foam

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Acoustical Materials

SoundproongIf the objective is to stop sound from entering or

leaving a space, then you will most likely need soundblocking or soundproong.

In general, if the source of the sound is gener-

ated in another room, space or from the outside andis transferring through a wall, ceiling oroor, into yourspace, then you need sound blocking or soundproof-ing products.

Sound AbsorptionIf the objective is to enhance the properties of

sound by improving speech clarity and sound quality,then the answer is sound absorption or acoustic en-hancement.

At home or in the ofce, high ceilings and largeopen spaces can create problems. Sound bouncesaround, creating annoying echoes and making it dif-cult to carry on normal conversations. Another idealscenario for sound absorption materials.

To summarize, if the source of the sound ofnoise is generated within the same environment thatrequires improved sound control, then you will needsound absorption products.



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Acoustical Curtains

Sound Deadening Paint

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Quiet Curtains and Drapes absorb soundwithin a room and block outside noise, and light. AllQuiet Curtains are beautiful window treatments thatlook elegant in both commercial and residential set-tings and will be an asset to any room.

STC 20 Quiet Curtains reduce noise by up to 20decibels! STC 20 Quiet Curtains use a powerful soundblocking lining to provide maximum sound protection.These curtains can be used to cover windows, door-ways and as room dividers.

Along with being water-based, it absorbs noiseand vibration, is sprayable, nontoxic, dries hard. Itworks really well for damping resonance in aluminum,steel, berglass, wood and poly-glass. It is nonabra-sive, anti-corrosive, protects against condensationand is ideal for automotive, industrial and railway ap-plications.

Noxudol 3101 Damping CompoundNoxudol

3101 is a water-based, viscous elastic compoundmanufactured specically to dampen unwanted soundand vibration. Noxudol 3101 converts sound energyinto minuscule amounts of heat energy resulting in anoverall noise reduction. In addition to its sound damp-ing properties, Noxudol offers rust protection and isre-retardant.



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Acoustical Baffles

Perforated Metal Tiles

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Acoustical BafesMade from Class 1 re-rated melamine foam,

WHISPERWAVE products are offered in standard andcustom sizes and curve patterns. WHISPERWAVEproducts are lightweight and easy to install. The line

also includes bafes, panels and awnings.

Acoustical TileMirroFlex is a decorated and perforated ther-

moplastic wall or ceiling tile usually supplied with pres-sure sensitive adhesive backing for ease of installa-tion.

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