PC Peripherals Ultimate Speaker Terminologies Info

[Quad Master]

Hi Guys

Was looking for some speakers when i came across this.

Many people here on TE would benefit from this.

When we go to the market to purchase any speakers it has
some certifications which we have a fair idea about but
very few like to go into the technical details about what
those certifications really mean.

Note: I deserve no credit for explainations of the terms explained.

The source for this info is "audiovideo101.com"

Some of the important terms are given below

5.1

Five point one is a term used to describe digital surround sound audio formats such as DTS and Dolby Digital. The five stands for five discrete channels of sound information. These channels are full range and fully digital – left front, front center, right front, right rear or surround, left rear or surround. The point one is a sixth channel designated for a subwoofer. This LFE (Low Frequency Effects) channel handles the lowest bass in recorded digital audio from 80 Hz down. A full 5.1 digital audio system can provide stunning realism and improved surround sound audio quality compared to matrixed or derived surround sound (which encodes multiple channels of information into two channels and then decodes the multiple channels when played back – in this format there are a maximum of four channels where the surround channel is a single, mono channel that is limited in frequency range and the center channel is also limited in its bass response).

Ambience Synthesis

Using surround sound technology and various matrixed or digital music or film modes to create the feel or ambience associated with a space other than the one in which the sounds are being heard. For example, a surround sound receiver may have a stadium mode, which uses surround technology to create the reverberations and apparent size of the stadium in a listener’s living room. The stadium’s ambience is obviously much different from that of the living room, but by studying the stadium’s feel and character that feel can be reproduced in the living room with the proper technology. Ambience synthesis synthesizes or attempts to replicate the ambience or feel of another space in some other location.

Dolby Digital

Discrete digital surround sound format based on Dolby’s AC-3 compression scheme to be found on DVDs, some laserdiscs and digital television (see 5.1 and AC-3).

Dolby Pro-Logic

Analog surround sound format using matrix surround technology to encode four channels of audio information (left, center, right and surround) onto two channels creating a surround sound sonic environment for properly encoded movies and other programming (see Matrix Surround Sound).

DSP (Digital Signal Processing)

Manipulation or alteration of analog signals (commonly audio or video signals) after conversion to a digital format. DSP includes such things as surround sound, compression, and more. Dolby Pro-Logic, Dolby Digital, and DTS surround sound formats are all forms of digital signal processing. The MPEG-2 compression scheme is also a form of DSP used with DVDs and digital television to convert video images to a smaller, easier to store format.

Digital signal processing is also commonly used with surround sound systems to alter the way stereo music is played back. For instance, a stereo recording may be altered so that when played over a full surround sound system it sounds as if the recording is being reproduced in a dance hall or a church. Such ambience enhancement modes can be found on most surround sound preamp/processors and receivers. DSP essentially takes a signal and does new things with it in a digital domain to achieve some desired effect.

DTS (Digital Theater Systems)

Discrete, digital 5.1 surround sound format used for movies and music; competitor of Dolby Digital featuring similar but incompatible compression and coding technologies to place six channels of sound on a DVD or on both digital audio tracks of a laserdisc

Matrix Surround Sound

Method of encoding more than two channels of audio into a pair of analog audio channels. Matrix surround sound is encoded during production and decoded by the proper surround sound processor.

The most widely used form of matrix surround sound is Dolby Pro-Logic with Dolby Surround used to a lesser degree. The Pro-Logic format separates out the center channel and a single mono surround channel by analyzing the difference between the left and right channels. The surround channel is limited in bandwidth to frequencies from 100 Hz to 7,000 Hz. The Dolby Surround format features only three channels, the left and right front stereo pair and a surround channel. Dolby Surround gives up the center channel along with some degree of fidelity in the surround channels. Pro-Logic is used most often, and Dolby Surround products should not be purchased (Pro-Logic is now very inexpensive leaving no reason to use the inferior Dolby Surround technology).

Since the channels in a matrix surround sound system are not discrete (totally separate), they tend to interact with one another and bleed into one another. Analog matrixed sound does not have the high level of fidelity and signal quality found in discrete digital formats. However, matrix surround sound is encoded on almost every movie produced since around 1980 making it easy to find and use. For matrix surround sound, all you need is a stereo VCR and a Pro-Logic decoder in a receiver or preamplifier/processor along with the necessary speakers and amplification. A matrix surround sound system can be purchased fairly inexpensively and there is a lot of program material available.

The matrixed format contrasts to 5.1 discrete digital formats, which feature six channels of completely separate, digital, full range audio. The digital technology, found in Dolby Digital and DTS, provides a superior sonic experience. However, it requires the addition of a digital surround sound decoder along with a digital surround sound source (typically a DVD or laserdisc player). Matrix surround sound has been a versatile technology that greatly improves the movie experience compared to straight stereo.

Surround Channel

Specific path of audio information, the channel, provided in a surround sound audio system to drive speakers situated on the sides or rear of a room primarily providing ambience and atmosphere. There are two surround channels, left and right. In 5.1 digital surround sound systems, each of the surround channels is fully discrete (completely independent) and full range (capable of sound throughout the range of audibility from 20 Hz to 20 kHz). Matrix surround sound formats, those that derive surround sound information by decoding it from two stereo channels, provide a single mono surround channel with limited bandwidth (100 Hz to 7 kHz only).

Surround channels are used primarily with movies and television shows to provide a feeling of depth and ambience. Information in the surround channel is generally meant to provide a sense of space and “you are there” reality. Particularly with digital surround sound formats, the surround channels can be used increasingly for more than mere ambience such as dialogue behind the audience, gunfire from the side of a room, etc.

Most speakers used for surround sound are either dipolar or bipolar in nature to provide a diffuse sound field in which the individual surround sound speakers are not easily localized by the ear. Surround channels have traditionally been less critical than their front left, center and right channel counterparts resulting in surround speakers having less power and sometimes less quality. However, for a truly enveloping and high quality experience (especially with digital surround sound formats such as Dolby Digital and DTS), surround sound speakers should be powered equally with the other channels and the speakers should be of similar quality and sound.

THX

Set of specifications and certifications designed by Lucasfilm to ensure optimum reproduction of movie sound and video in movie theaters and home theaters (Home THX program).

THX was originally started to ensure high quality sound in movie theaters. For that purpose, it included specifications for ambient noise (noise from air conditioners, other theaters, etc.), projection screen brightness, sound pressure level (volume), quality of speakers and amplification, etc. THX was meant to bring the quality of the mixing studio where movie soundtracks are produced to the theater going audience. THX strove to recreate the experience the director had and intended as he and his staff created and edited the movie. To this end, THX became very successful and is known as a symbol of quality in movie theaters around the world.

The Home THX program began to bring the director’s vision into the home much as it had been done for the movie theater world. Home THX certifies products that meet certain minimum specifications, requires certain functional components in the electronics and particularly in the preamplifier/surround sound processor, sets specifications for speakers used, and certifies installers to create and install Home THX home theater systems among other things. The various minimum aspects of a full THX certified home theater system include a THX certified preamplifier/surround sound processor, certified amplifiers, certified interconnect cables and speaker wire, certified subwoofer, certified surround channel speakers, certified center channel speaker, and certified front left and right speakers. THX also certifies laserdisc and DVD players, equalizers, receivers, and acoustically transparent projection screens (screens with microscopic holes allowing speakers to be placed behind them with little or no sound quality degradation).

THX components are typically all of high quality since they must meet fairly stringent guidelines. However, not all THX equipment is excellent and certainly equipment that does not feature THX certification may be of THX quality or better. THX sets minimum requirements, but products may certainly exceed those requirements.

THX certified speakers must exhibit certain characteristics. The subwoofer must play from 80 Hz down to or below 20 Hz. The surround channel’s speakers must be of a dipole design (two sets of drivers on either side of a cabinet wired out of phase), and they must be placed on the side walls directly out from the listening position and up about six feet. The three front speakers (left, center, right) have to reproduce sound in a broad horizontal plane but be fairly directive in the vertical plane (this is to reduce floor and ceiling reflections while allowing the greatest number of people to hear the sound in an acceptable way). The speakers must be able to achieve high sound pressure levels for extended amounts of time without distortion.

THX certified preamp/processors must have Dolby Pro-Logic surround sound capability at a minimum (many now have Dolby Digital and/or DTS as well). The basic surround sound function is then modified with THX designed and licensed technology (Re-Equalization, Timbre Matching, and Decorrelation).

Re-Equalization generates a slight roll-off of the high-frequencies in movie audio to compensate for an artificially boosted high frequency used due to movie theater acoustics. Movie theaters roll-off the highs slightly due their design so a little high frequency signal boost is applied to compensate, however, that boost is not need in a home theater resulting in an overly bright sound.

Timbre Matching alters the timbre of the surround channels to more closely align with that of the front channels. Due to the surround channel speakers’ position on the wall above the seated position their timbre or specific sound quality aspects are changed versus the main speakers requiring adjustment to more closely match all the speakers in the system.

Decorrelation splits up the mono surround sound channel in an analog, matrix surround program into two channels and slightly differs the information sent to each channel so that the sound field is more diffuse and encompassing. This technique is not used with 5.1 discrete digital surround sound systems since they possess stereo surround sound channels.

THX certified amplifiers must meet certain qualifications such as the ability to generate sustained output into 4-ohm loads with low distortion.

Excellent surround systems can be developed and installed with no THX certified components at all, or systems can be designed melding THX certified components and non-THX certified components with excellent results. In order to achieve the greatest benefits of THX using a minimum number of THX components, one needs a good quality subwoofer, a THX certified preamp/processor, and some dipole or bipole surround speakers (they do not necessarily have to be THX certified). In order to create a true THX system, however, all THX components should be used throughout the sound chain.

THX has served to enhance and advance the state of the art in home theater systems, and a THX system using good quality components is a sure-fire way to get a top-notch movie theater experience at home (when the system is properly installed and designed to meet the needs of a particular space).

Hope you guys find this info helpful

 

[Switch]

Some nice info there quady... Nice find...

 

[Anish]

Good info, covers mostly the basics, not the high-end audio terminologies...

Some more :

HCC = Homogenised Crystal Copper

Head Amplifier

An Amplifier that brings the I/O of a transducer to a common standard. While it may be confusing why a tape head amp always includes corrective EQ while a moving coil pickup head amp never has any such this has a really simple explanation, it's the standard they are amplifying to that dictates it, a pickup head amp is amplifying a signal to that of an common MM input of a amplifier that is already specified to have a corrective EQ onboard, while the tape head amp is bringing a signal to a line, pro or microphone level standards and all of them expect a straight signal and thus the preamp needs to perform any necessary alterations to the transducer signal before going any further. The term "head amp" comes from electric record cutters, but you had to buy an amplifier to suit the transducer which was called a cutter head and since the transducers of tape recorders were called heads as well the name stuck for all transducer amplifiers that amplify to or from a level signal.

High Blend

A circuit used in stereo FM tuners that blends the high frequencies into a mono signal, this is useful with low signals strength and with bad receiving conditions were you can get rid of the stereo noise in the higher frequencies since a lot of the noise is out of phase between the channels and hence disappears when you revert it to mono. The result is to greatly reduce overall noise but still give you a stereo signal in the lower frequencies. In personal and car radios this circuit is usually permanently on without the manufacturers ever telling you so, but this is a very useful function that should be on every tuner as an option (preferably as a variable option) and an inclusion of it is a pointer towards a careful design. Some manufacturers also have an automatic blending circuit which detects the presence of stereo noise and adjust accordingly, this is usually called AutoBlend.

HDCD = High Definition Compatible Digital

A simple but ingenious technique whereby a digital signal of 20 bit's or higher is slightly compressed and dithered into a 16bit 44KHz signal (the standard used in common CD's), then "hints" gained from original signal are buried in the least significant bit of the audio stream and on playback extracted by a digital filter that uses them to expand the data. All this resulting in a slight improvement of bandwidth and a not inconsiderable improvement in dynamics, the technique is not limited to CD standard bit rates but is most useful there since it allows it use with equipment that plays back standard CD's or comparable media, the HDCD technology does however not offer any improvements when the processed signals has a resolution higher than 24 bits. Note that the introduction to the HDCD technology on the company's homepage is a bit misleading and also that the original name was High Definition Compact Disk and you may have seen it defined and used as such but Philips lawyers where not happy about the usage of their CD trademark it was soon changed to the current one. Official homepage.

HDTV = High Definition TeleVision

A television system with higher resolution than the common terrestrial standard. This is not a new term, it has actually been used since the 1950's (UK) : where it was used to describe the 625 and 525 systems that where proposed to replace the 405 line standard that had been used in the UK since 1936, initially the UK was meant to use the 525 system but in the end and adapted the PAL system in 1964. 1980's (Japan) : Used to describe the HiVision system introduced in Japan in the latter half of the 80's. 1990's : A standard initially formulated in the USA and commonly referred to as just HD, intended as an answer to the Japanese HiVision format but ran into technical and political difficulties before finally being standardised in 1997 and then with the participation of European companies, has gained a foothold in the USA since quality of even the lower HD resolutions offer considerable improvement over NTSC, however in has seen almost no take-up in Europe since the difference between HD and PAL is less than was anticipated so most broadcasters have concentrated on introducing DVB.

HiVision

A widescreen high definition television with 1125 lines and 30 frames a second compressed using the MUSE standard, designed in Japan in the late 70's and early 80's and intended to replace the archaic NTSC standard but the American government resisted the usage of something not "home made" so it was never deployed outside Japan.

Humbucker

Used for transducers that have some sort of shielding or other design features that minimise the injection of hum from internal or external sources, this word sees little use these day's in audio circles but is used in musical instrument pickups and suchlike.

i-Link See --> 1394

Impedance

The combined effect of resistance and reactance in a device, the reactance can be inductive or capacitive. While inductance is measured in ohms like resistance on it's own the impedance characteristics of a device have a tendency to vary somewaht depending on the frequency that the device is opeerating with unlike resistance.

I/O = Input/Output

A units interfaces to other devices.

IP = Intellectual Property

Basically any idea that you can legally claim ownership of, either by registering it as in case of Trademarks and Patents, by automatic grant of rights as in Copyright or by taking matters into your own hands by making it a "trade secret" (i.e. hiding it under your bed).

IPS See --> Tape Speeds

I2S = Inter-IC Sound

A high speed serial bus standard for use with digital audio and/or video communications developed by Philips in 1986 and based around their I2C chip-to-chip communication standard (aka 12S), were it differs from most such serial systems is that high resolution clocking signal is sent alongside the data itself to ensure synchronisation and reduce or eliminate problems such as Jitter. It was originally designed for on board communications between electronic parts as can be seen from the name and is used as such on everything from high end digital televisions to mobile phones, but has more recently been seen used on high end audio as an external interconnect standard in the form of I2S Enhanced. Basically an IS2 bus consists of 3 signal paths, one has 2 channels of audio or video data multiplexed onto it using TDM, the second channel has clock info and the third is a word select line. Get more info from Philips here (PDF file) or information on the I2s Enhanced here.

K7 = kah + sept = Cassette

Common French shortening for a Compact Cassette.



Kunstkopf

An interesting and technically sophisticated recording system for making Binaural recordings. Recordings are created using a microphone called Kunstkopf (or dummy head) that is actually modelled on reasonably anatomically correct in shape and external density, has microphones located in the ear cavities were the eardrum would be and sits on a resonating chamber that simulates the chest cavity of a human. This produces a recording that has an uncannily lifelike quality when listened to on headphones but has a somewhat limited compatibility with normal loudspeaker systems, the recordings are normally slightly equalised to enhance that compatibility. This technique has got something of a bad rap due to a number of recordings made and distributed in the early 80's that were done with home made kunstkopf systems that were so amateurishly done that the binaural effect was severely limited, this gave rise to the myth that recordings made with the system are "head dependent", i.e. that the binaural effect was dependant on the shape of the listeners head. There are loads of such imitations of the original system that usually simplify the head structure too much to be fully functional, skipping the resonating chamber is fine for scientific and technical purposes such as noise monitoring an analysing but almost absolutely necessary for audio related recordings, the head needs to have a nose and a reasonable emulation of an outer ear and an ear canal, without those last 2 it's simply useless. This is the correct name for both the technique and the microphone, the technique is sometimes referred to as "dummy head recording".

Magazines

A sort of a homepage but done on paper, outdated format but still mildly popular with geriatric audiophiles.

Magpie

An obsessive collector or hoarder of old junk, as opposed to someone who collects vintage pieces systematically, although the end result has a tendency to look and smell similar. This is an English term but local variants of the language have other naturalistic idioms, in the USA the term Packrat is the most used one etc.

MIDI = Musical Instrument Digital Interface

A serial digital control interface for musical instruments.

Mod-tro = Modern retro

Japanese slang for modern equipment with retro looks and asthetics.

Mono = Monophonic

In Hi-Fi : Any audio system that gives out a single audio signal, this is regardless of the number of loudspeakers or amplifier channels used. In music : An instrument that is only capable of producing one note at a time. Dual Mono : A design feature in 2 channel stereo audio systems were the 2 signal paths are kept completely separate from each other both electronically and mechanically, high end variants of this type of design also have a separate power supply and transformer for each channel.



MPX = Multiplex

Usually seen used for the Multiplex filter on analogue recorders, FM radio uses a 19KHz multiplex pilot tone to control the demodulation of the radio signal, this is not properly filtered out by most tuners and is thus still present in the audio signal that you get from the tuner, this is mostly inaudible but creates problems when you use some noise reduction system that use de emphasis as the tone interferes with the tracking of the system and in older recorders in particular it also created problems with the bias circuit for similar reasons.

Muntzing

The practice of removing all parts and features not needed for a basic operation from an electronic design for cost saving purposes. Named after Earl Muntz who ran a a small consumer electronics empire in the southern USA in the 50's and 60', he sold good such as TV's and car radios that were designed down to a price, he was in particular fond of clipping out any capcitors used for somoothing purposes, all this resulting in TV's that where cheaper than the competicion but had a tendency to work only under ideal conditions.

 

[kauzy]

gud find bros

 

[Anish]

Neodymium
A metal alloy with dense magnetic field that unlike most other hard magnets with similar characteristics is neither outrageously expensive nor difficult to fabricate, using this material in a transducer such as a pickup or a headphone means higher efficiency and thus in most cases a more accurate sound. Neodyium is a popular Japanese variant on the spelling used by Furuyama Audio Lab (FAL) for instance in their local literature, but that company BTW claims to have invented the alloy in the early 1970's.

NOS = New Old Stock
A new and unused example of a product that is no longer being manufactured and usually outdated. Typically unsold stock from a dealer, distributor or manufacturer.

Nostaklígja
Icelandic slang, a combination of the French word Nostaglia and the Icelandic word klígja which denotes the gall like taste you get in your mouth just before you throw up. Used were a overly romantic view of a bygone era transcends good taste and/or common sense.

NTSC = National Television System Committee
An USA based organisation but this term is usually used to denote the analogue terrestrial broadcasting standard formulated by this committee rather then the organisation itself..

OEM = Original Equipment Manufacturer
An OEM is a company that designs and manufactures products for a third party, usually another manufacturer, a brand or a trading entity and the product bears the brand name of the 3d party. This is not to be confused with companies that do not design products but just manufacture them for the company that designed them, those are referred to as subcontractors. Please note however that like subcontractors an OEM manufacturer do not sell their products to end users, dealers or distributors and thus are not responsible for warranties or supplying information on older products etc., that responsibility is on the hands of the supplier of the product. They do however own any IP rights to the devices since they are the originators of the design, that means that while they did make a product they are bound by a contract to their supplier not to give out information on it and usually do not answer queries from end users for that simple reason, but also that the status of the brand that sold the device has no bearing on the intellectual property rights, so even if the company that sold the product originally has ceased trading and their brands and IP has technically or effectively been placed in the Public Domain you cannot distribute or make use of the IP without permission from the OEM.

OFC = Oxygen Free Copper
Copper wires manufactured so that there are no oxygen bubbles inside the wire or rather an absolute practical minimum, the wire is then plated with another material, usually metal, to hinder oxidation from the outside. The plating process is not strictly necessary but should improve performance over the long run since copper oxides are bad conductors, silver oxides are however and one of the reasons some people prefer that material despite quite a considerable more cost.

OFDM = Orthogonal Frequency Division Multiplexing
A digital broadcasting technique, the signal is sent out as a Spread-Spectrum with quadrature multiplexing but what makes this different from analogue broadcasting is that pulses are modulated over the zero crossing of the pulse that comes before them, the aliasing errors generated by this are ignored by the receiver since it only needs to work out if each pulse is a 0 or 1 with the exact shape of the pulse being of no importance. This technique is used in the European terrestrial digital TV standard DVB to cram 70 channels or more onto a single broadcast signal and recently Siemens has shown a development of the system that can broadcast 360 Mbps in real live conditions.

Osbourne Effect
Self harm inflicted by a company's marketing department by pre announcing new products while they still have warehouses full of older products. Named after Adam Osbourne, a noted PC & technical writer in the 1970's that founded Osbourne Computers on the proceedings of the sale of his publishing business, this company went on to become the fastest growing computer company ever, but managed to self-destruct when they pre-announced a revolutionary new version of their computer at the same time as the industry was facing a minor slump.

OTL = Output Transformer Less
A design methodology for valve amplifiers but in normal circumstances a transformer needs to be placed between the valves output and the loudspaker terminals for Impedance matching etc. Getting more popular in recent years in search of valve amplifiers with less colouring but in the 40's and 50's most OTL designs were attempting to archive a usable Class B design in search of more output power.

OTR = Old Time Radio
American idiom for recordings from the golden age of radio, which in their case was from the late 1930's into the latter half of the 50's when radio was more a source of information, propaganda and spoken entertainment than a music carrier. TV took over these role fairly quickly after it's introduction and most spoken word production ceased in the 1950 with the exception of religious broadcasts.

PA = Public Announcement
A term used for the types of Sound Reinforcement systems that are specifically designed to carry verbal information rahter than music.

Parallel Interface
A digital interface capable of sending multiplies of bits usually a byte, at each clock cycle, as opposite to serial.

PASC = Precision Adaptive Sub-band Coding
A variant of the Musicam perpetual coding & compression system that was developed by Philips for use in the Digital Compact Cassette and early versions of it are very similar to a MPEG layer 1 codec. Basically an audio signal is split into bands in a linear fashion (i.e. same width regardless of the frequency), all data that is duplicated inside each band is then removed, all data that the processor thinks the user will not hear due to the masking effect of the ears and all data that the processor thinks is superficial (i.e. silence) is also removed until the data has reached a reduction of 4:1. Much better worked out than its Sony ATRAC counterpart but no development has been done on the codec since 1997 so it's getting a bit stale.

PCB = Printed Circuit Board
A board usually made out of plastic or plastic like materials that has electrical conducting tracks printed upon it, electronic components are soldered onto the board and the conducting tracks become the electrical connections between the components. In most cases the tracks are only printed on one side of the board for economic reasons but were more complex electrical routing is required such as with advanced digital products there may be layers of tracks, this is archived by making very thin boards, a number of which are then glued together to form one board, this type of board is usually referred to as a sandwich.

PCM = Pulse Code Modulation
The most common approach used to convert analogue audio information into digital information.

PD = Phase change Dual disks
A type of rewriteable optical drives drives designed by the Matsushita company, with a maximum capacity of 640 Megabytes, outdated now and were never as reliable as the MO drives from Fujitsu but Matshushita still provides support for the format in newer DVD-RAM drives that utilise similar technology and caddie system which can read older PD disks, so all is not lost if you have music data stored on some of these.

PD = Public Domain
Any sort of intellectual work or IP were the creator of the work has expressively denied any rights to his work or were the rights granted have run out and can thus be used by anyone for any purpose without limitations or restrictions.

Power Conditioner
A device intended for use with hi-fi products that "conditions" the electric power signal in order to make your existing system sound better or in the case of transistor amps to be more efficient. This is archived typically through the use of active or passive filtering but more exotic variants exist. This type of device is increasingly popular in countries such as the USA were we see more variations in the quality and age of electrical installations and infrastructure than we typically see in other western countries and in the UK were standards and work practices in electrical wiring date back to the stone age, but theoretically a conditioner (depending on design) should offer at the least a minimal benefit to any system regardless. We first see these units in used in the medical sector were they were used to shield very sensitive equipment from minor variations in input voltages and shapes but those devised leaked into the hi-fi world in the 80's. You should not confuse them with battery based power back-up devices, these have an electrical output that is not sinusoidal which may cause trouble with audio equipment with linear power supplies, in particular with amplifiers since the further away from a pure sinus wave the power signal is the less efficient the amplifier becomes. There do exist however battery based power conditioners that mix rechargeable battery technology with more normal filtering techniques to create ultra pure sinus waves, these are rare and expensive however. Alternativly : A device expressively designed to con nonplussed audiophiles out of money.

Psychoacoustic Masking
Actually a set of techniques used to "fool" the ear or rather to get around various shortcomings in devices or techniques by exploiting certain defects, non-linearietes and other abnormalities in how your ears work and how the brain makes use of audio information. The simplest and the most commonly seen technique is to make use of the integration tendencies of your ears, for instance you cannot detect distortions that are less than 1ms since the ear will simply ignore them and integrate what became before and after into one distortion free sound, so if a distortion can be shaped into extremely sharp transients by concentrating the energy, you will not hear it.

PWM = Pulse Width Modulation
In amplifiers : A technique were an audio signal is converted into pulses with the width of the pulse representing it's slope, the pulse signals are sent to a dual output stage that switches between + and - and the speaker then averages out the signal thus reconstructing the slope. Very efficient, typically over 95% in modern examples and theoretically should sound excellent but the switching action of the output sage creates noise and the higher the frequency is, the more noticeable the noise and related distortions are. This technology is widely use in subwoofer applications were this phenomenon is less of a problem. PWM amps are sometimes described as a "digital amplification", that's not quite correct although they can be viewed as hybrids, but it is possible to make a converter less amplifier using this technology and driving it directly with PCM or DSD streams. Better sounding propriety variants of this technology have been developed over the last few years by a handful of companies, they all involve amplifiers operating at very high switching frequencies that use computer circuits to modify the behaviour of the output stage in real time. In electronic music : This term is used when an oscillator playing a pulse waveform has the width of the pulse changed by a signal from another waveform generator, an event generator or a tactile interface.

Quad = Quadraphony
4 channel stereo although some 3D systems that utilised 4 channels also used this term.

RF = Radio Frequencies
Basically all airborne waves that you cannot hear or see, or in other words all parts of the frequency spectrum that fall above or below your hearing threshold, which is typically around from 30 ~ 80 Hz to about 12 ~ 16 kHz for an adult human but varies between individuals (in technical lit. usually 20Hz to 20KHz). Usage is changing slightly, traditionally this was just the parts of the FS that you associated with radio communications (i.e. nothing above microwaves) but lately there is a tendency to include the whole shebang including light waves and even in some cases other radiation etc. BTW radio communications can happen inside the hearing threshold (and have be used as such in extreme cases (submarine comms or LFR, VLFR is/should be below the hearing threshold)), but for obvious reasons not a recommended practice on land, naturally occurring waves in the 50 to 1100 Hz band are sometimes referred to as VLF radio waves but the correct term for them is actually "sound".

RIAA = Record Industry Association of America
USA based association of record manufactures and publishers. On those pages here usually used in reference to the RIAA equalisation curve, but that is a compensation method used on modern microgroove records. Official homepage.

Rochelle Salts = Sodium Potassium Tartrate
Crystal structure that is used in low budget transducer such as microphones and pickups, a very efficient as a transducer and cheap to make but it dries up with age and thus needs replacing every now and then and has for the most part been replaced with ceramic elements which show a similar behaviour but are more robust and have a greatly extended lifetime.

RS-232/RS-422
A standard for serial digital communications that is so widespread in the computer and CE industries that the word serial is used as a synonym for it. RS-232 was initially put forward in 1961 as a standard interface for modem control and therefore has terminology which assumes a control unit and a slave but modern variants are fully bi-directional as far as control is concerned. The standard is too slow to carry audio data with modern variants of it not exceeding 115K bits in most cases but this is more than enough to carry control information and program data and it's exactly in those situations were you will find it used. Since even the cheapest low power microcontrollers have a serial port interface built in which means that implementing it is free or at the least only at costly as the connector used from the designers point of view, you will find that audio devices such as DAT recorders, AV amplifiers and even something as cheap and simple as remote controls have external, internal or hidden RS-232 interfaces that can be accessed by technicians for analysis or upgrades, or by end users for remote control, synchronisation or other utilitarian purposes. There was for instance for a time a serial interface on every Sony product that featured a recording button except for the cheapest systems. The latest published standard is RS-232D xxx which incorporates improvements found in CCIT V24 (USA) and in ISO IS2110 (Europe) but there may have been updates to those standards since the last time I fell asleep reading technical manuals. RS-422 is an improvement of the 232 standard that features balanced connections and has data transfer rates of up to 10M bits, now that is enough to carry audio data and you will find variations of this standard used in professional digital audio recorders, most Sony professional digital recorders had this at the least as an option and even DSD interfaces from the company (for recording SACD material) sport such an interface. Other variations on this standard exist including RS-423 (Unbalanced 422 variant) and RS-449 (High speed 232 variant) but are seldom used outside the computer communications industry.

..........

 

[Anish]

SECAM = Sequential Couleur Avec Memoire

That would translate into Sequential Colour with Memory or something suchlike, variant of the PAL system used in France, parts of French Africa and parts of Eastern Europe, in the last case slightly modified.

Serial

Lit. in series or in sequence. Serial Interface : A digital interface that sends out data one bit at each cycle so it's throughput is determined by it's clock speed, see RS232 and also parallel interface. Serial Number : A number or other unique mark used differentiate an individual unit from otherwise identical ones. Serial Production : Mass produced, as opposed to hand made, individually made or prototype.

Shellac

Wood sap that has been digested by flies and is left on the bark of trees in a tiny shell like form, harvested by hand in India and other Asian countries and was popular as a binding agent for records prior to the introduction of synthetic alternatives but was expensive and usually used with other binders and fillers, a typical shellac record having no more that 15% of it's mass made out of the material. Origin of the word is in Sanskrit and the current English spelling is the approximation of the modern Indian word, the currency restrictions placed on Indian businesses in the 20th century meant that the locally harvested shellac was used in the production of records much longer than it was in the rest of the world, 78 Rpm. shellac records were issued there until the late 70's at the least.

Sound Reinforcement

Traditionally this term was used for exactly what it states, i.e. the amplification of audio signals in a "live" situation, be that a sound system for a live concert or a theatre of any sort, or a Public Announcement type system etc. In the last few decades the usage of the term has expanded to include most sound installations both permanent and portable, and in practice covers almost any type of sound system installation except those used in homes and recording studios.

SPDIF = Sony/Philips Digital Interface

A serial digital audio interface cooked up by Sony and Philips when they were designing the Compact Disc, it only offers basic transfers of an audio signal with no provision for synchronisation or error correction (will need an external Wordclock for sync capability) and thus is prone to problem such as Jitter. The standard provides for transfers using an coaxial cable terminating in a common RCA connector or via an optical cable, while theoretically the optical option should be the better choice, the coaxial variant gives better results in real life situations for a variety of reasons. Not to be confused with SDIF, another digital audio interconnection standard.

Special

On input selectors : This is a synonym for AUX. On cassette recorders : This denotes eq and/or bias settings for chromium tape formulations on early Japanese cassette recorders.

Spread-Spectrum

A radio broadcasting technique whereby the signal energy is spread over a range of carrier frequencies rather than a single carrier, this technique uses much less energy pr. information unit than if a traditional carrier method is used.

Stereo = Stereophony

Any audio system that attempts to give directional information or appear to do so, or in other words the opposite to Mono and not a term that is to be specifically applied to 2 channel systems only. While this term covers 2 dimensional system like the common Binaural systems and the various multichannel and Matrix systems commonly referred to as Surround Sound systems it is debatable if the term covers 3D systems such as 4 channel Ambisonics or the "Tomita Quad" systems and it was not the intention of the people that coined the term. Common usage/slang : As a synonym for a music system and in the 60's as a synonym for hi-fi.



Supertweeters

Basically a tweeter that not only will operate with frequencies well above the audible range but will do so with a reasonable linearity. Research into psychoacoustics in the resent years has shown that despite being unable to hear frequencies in the 25 to 40KHz range directly, most humans find loudspeaker systems with tweeters capable of operating in that range to be audibly better that those with normal tweeters that only go up to 25k or so, a fact that has not bypassed high end loudspeaker manufacturers in search of new gimmicks, dogs love this development of course. Not to be confused with piezoelectric tweeters that were sometimes called supertweeters when they were introduced in the 60's, such types can operate in this part of the spectrum but they were not designed with that application in mind and thus aren't usually very good at it.

Surround Sound

A synonym for stereo eg. any 2 dimensional audio system that gives the effect of "surrounding" you with an audio signal rather than come from a single source, it is often used for marketing purposes to differentiate multichannel or Matrix stereo systems from traditional Binaural ones.

Tape Speed

The speed at which a tape travels across the recording or playback head measured in centimetres per second. Most open reel recorders offer a choice of recording speeds so that the user can choose between recording quality and length, this is also possible with some cassette decks and other analogue recording formats, but by no means common. In the English speaking world tape speeds are often expressed in the archaic IPS or inches per second, note that while ips is indeed an abbreviation and should be spelled all caps there is a long running tradition of using and spelling it as a word esp. in England. The most common speeds are : 2,38cm (15/16ips), 4,75cm (1.7/8ips), 9,5cm (3.3/4ips), 19,05cm (7.1/2ips), 38,1cm (15ips) and 76,2cm (30ips), those numbers are often rounded nb. The origins of the tape speed standard are simple, the first tape recorder from Telefunken ran at 77 cm and later portable models from the company featured speeds that were divides of that number, and since stolen Telefunkens were heavily used by the US broadcasting industry after WWII the first US based manufacturers of recorders needed to make their equipment compatible with pre-recorded tapes and averaged the speed to the nearest inch, this is also the reason the early Ampex units used DIN spools.

Terrestrial

A term used in the broadcasting industry to descibe radio broadcast that originate in the earths athmosphere as in traditional TV and radio broadcasting, opposed to signals beamed in from space or brought to you via cable.

Transducer

Any device that converts mechanical or acoustical energy into electrical energy or vise versa. Phonographic pickups, loudspeakers and microphones are all examples of a transducer. There term is also used for mechanisms that convert mechanical energy into acoustic energy and so on, but those have not been used in the audio industry since the days of wind up gramophones so the simplified explanation given here above is more pertinent.

Transient

Term literally means something of a short duration but it's usually meant to mean a sudden and sharp increase in energy or information volume (i.e. a "spike" in a waveform), this can cause all sorts of problems in that either the device has not expected this amount of energy and thus reacts by ignoring everything beyond it's expectations causing distortion (in extreme cases can damage the equipment) or the equipment can react and adapt to the transient but by doing so creates abnormal conditions for the normal signal. For instance in loudspeakers a transient can cause the woofer to travel to it's extremes, this can not only mask or distort the sounds immediately around the transient since the woofer cannot react to them but the counter force will cause sounds that come after the transient to be masked or lose their timing coherence (their attack and decay characteristics are partially lost resulting in a muddled sound).

Ternary

The representation of number in powers of 3, this is occasionally used as the basis for a digital system mostly as a "last resource" when you need to build a system that has to be compatible with an older binary based standard but also to offer a higher resolution as with Supermidi, in such "upgrade" cases the system used is typically Balanced Ternary using the digits 0, 1 and -1 rather than the usual 0, 1 and 2 as is used in logical applications (i.e. a normal ternary system), the legacy systems ignore the negative and see the data as binary while the ternary based systems take advantage of it.

Uncle Technology

A derogatory term taken from the computer industry, either technical advise with not even a tenacious link to reality or a hardware/software modification by someone that has no idea what the is doing. This sort of technical expertise is usually dispersed by your 13 year old nephew, some unidentified uncle (hence term), or this website.



Unit Audio

Archaic English term for hi-fi separates occasionally used in the UK, note that the term meaning has changed a bit over the years, in the 50's and up to the late 70's any audio equipment that had the speakers separate from the rest of the system was considered unit audio, traditional consoles having the speaker or speakers built into the base unit. In fact to qualify as unit audio, a console by definition only had to have one speaker adjunct from the base, this usage of the term stopped when consoles were replaced in the marketplace by Music Systems and if you see it used today it is as a synonym for separates.

Upsampling

Usually when a DAC has a higher bitrate and/or sampling frequency than the material it's converting what you gain is basically improved headroom since the data that the converter is getting is still confined to the lower bitrate (i.e. the same granularity of a signal), upsampling is a technique whereby the original digital information is first converted into the maximum bitrate and frequency that the converter is capable of prior to converting the information into an analogue signal, this means a although the amount of original information is the same the converter is getting more detailed information and thus puts out a more granular signal. The net result of this is highly dependent on the design of both the upsampling software and the DAC but can be quite an improvement. Despite claims by certain UK based manufacturers of an upsampling capable CD players, a 16bit signal converted into 24bit/192KHz (or whatever) will never be as good as material originally recorded in that resolution.

VCA = Voltage Controlled Amplifier

Just that, usually a small signal amplifier that can be controlled by a voltage for automation or remote control purposes, this is useful in compressors, noise reduction units and mixers of any kind (but not in volume controls Nb.). A difficult device to manufacture, the quality of the VCA is often the deciding factor in the sound quality or accuracy of the unit that's built around it.

Wordclock

A master clock signal sent out by a digital audio playback device such as a DAT recorder or a CD transport to a receiver such as another recorder or a D/A converter side by side with a digital audio signal such as SPDIF, this means that the receiving device input converters/processors are being controlled by the clock of the device that is sending the audio signal, although in hifi it is often the other way around with the receiver controlling the sender and in professional audio circles a master clock is often used but that is a specially built high precision device that will in turn control multiple transmitting and receiving devices. The use of a wordclock minimises Jitter and other clock mismatch errors, this is especially important when further conversion has to take place on the receiving end such as sample rate conversion or dithering etc. Primarily seen in the pro audio industry although not unknown in high end audio products, the use of a wordclock obviously requires the correct I/O on both the transmitting and the receiving device and the connectors are usually BNC.

XRCD = Extended Resolution CD

A set of standards put forward by JVC that specifies how a CD should be mastered to a great detail. It's important to note that this is a standard, not a technology like HDCD and that JVC's classification of it as a "high resolution format" is misleading at best, but as a sort of a quality assurance it's a "good thingâ„¢". Official homepage.

Source

.....

 

[Nikhil]

Another small addition --- THX = Thomas Holmann Experiment. He was one of the engineers working with George Lucas.

George did not like the way his Star Wars movie sounded when he went to watch it in a common thetare. Then he decided to make some sort of standard so that movies sound the way for the common public the way they sound in the studio.

 

[Quad Master]

@Anish - I didnot posted all the definitions here on TE.
As i wanted people to check out more info on the source site.
So it would also have got hits as its there hardwork behind it not ours.

 

[MAGNeT]

nice info.......................but 5.1 is said as 5 point 1 or pronounce something else??????other info ill ask l8er
edit::as i m within time...i m editing this post nikhil....i heard some other word...5 isto 1 or somethin else......... its not 5 point 1 i guess....

 

[Nikhil]

huh?? I don't get you magnet. If I understand you correctly, then yes... 5.1 is pronounced as 5 point one.

 

[zhopudey]

A couple of basic things most of you might not be aware of -

PMPO ( Peak Music Power Output) - It means......absolutely nothing at all :bleh: (technically speaking of course).
Every electrical and electronic component has a safe working limit. i.e., only so much current can pass thru it, or it can sustain so much voltage, or else it will work only in a certain particular temp range. Similarly, speakers have a maximum power rating, which means the maximum wattage that can be applied before the speaker blows.
Now, say a speaker has a continous power rating of 50W. That means, it can work with 50W happily for years and years. But if you feed it 100W, it might work for a couple of hours, then blow. With 200W, it could take 1/2 hour. With 1000W, maybe just a minute.
So, any component will *work*, under any condition, for at least a fraction of a second. ( say like an OC which POSTs but doesnt boot windows). So, unless you know that the system is Prime-stable, its no use.

Moral of the story - PMPO is bull-shit. It is cow-dung. ( Well actually, cow dung has tons of uses, so PMPO is worse than cow dung).
Am very sleepy now. Will burst the bubble on RMS in the evening.

 

[Chaos]

This thread needs to be stickied!

 

[zhopudey]

OK, back to class. So now we know PMPO is baaadddd, how do we buy audio stuff? Simple - use the RMS rating.

audiovideo101 defines RMS as:-
RMS (Root Mean Square) Generally, the average continuous power output an amplifier is capable of producing; power output an amplifier can produce consistently over extended lengths of time.

So thats good, right? Only if the marketing chaps were goody goody fellows.

Se, the human ear can hear sounds between 20hz and 20khz. (approx). So, the amp should reproduce this entire frequency range faithfully. My old Sony mini compo reads 100 + 100 Watts proudly. So I opened up the manual, and checked the specs. They read

Power Output: 100W/ch (rms), 1khz, 10% THD

Huh? what does that mean? It means my deck can reproduce a 1khz signal at 100W rms, that too with 10% THD ( Total Harmonic Distortion). What happened to the rest of my music?

In comparision, here are the specs of the NAD 320 BEE, an excellent value for money amp, for around 20K (not sure of this).

Continuous output power: 50 W
IHF Dynamic Power at 8 Ohm: 110 W
IHF Dynamic Power at 4 Ohm: 160 W

Frequency response at -3dB: 3Hz - 70kHz

Power unit THD 20Hz - 20Khz: 0.03 %

Pre unit S/N ratio, A-weighted: 106 dB

Power unit S/N r., A-weighted: 100 dB
at ref. rated power: 117 dB

S/N ratio, A-weighted,
from CD input to speaker output,
at 1W/8 Ohm: 93 dB

Input impedance: 200k Ohm / 320pF