Showing posts sorted by relevance for query Quadraphonic. Sort by date Show all posts
Showing posts sorted by relevance for query Quadraphonic. Sort by date Show all posts

Sunday, January 22, 2023

Quadraphonic

Quadraphonic (pronounced kwod-ruh-fon-ik)

(1) Of, noting, or pertaining to the recording and reproduction of sound over four separate transmission or direct reproduction channels instead of the customary two of the stereo system.

(2) A quadraphonic recording.

(3) A class of enhanced stereophonic music equipment developed in the 1960s.

1969: An irregular formation of quadra, a variant (like quadru) from the older Latin form quadri- (four) + phonic from the Ancient Greek phonē (sound, voice).  All the Latin forms were related quattor (four) from the primitive Indo-European kwetwer (four).  Phonē was from the primitive Indo-European bha (to speak, tell, say) which was the source also of the Latin fari (to speak) and fama (talk, report).  Phonic, as an adjective in the sense of “pertaining to sound; acoustics" was used in English as early as 1793.  Quadraphonic is a noun and adjective.

Those for whom linguistic hygiene is a thing approved not at all of quadraphonic because it was a hybrid built from Latin and Greek.  They preferred either the generic surround sound which emerged later or the pure Latin lineage of quadrasonic (sonic from sonō (make a noise, sound)) which appeared as early as 1970 although it seems to have been invented as a marketing term rather than by disgruntled pedants.  Quadraphonic, quadrasonic and surround sound all refer to essentially the same thing: the reproduction of front-to-back sound distribution in addition to side-to-side stereo.  In live performances, this had been done for centuries and four-channel recording, though not mainstream, was by the 1950s, not uncommon.

Surround sound

Quadraphonic was an early attempt to mass-market surround sound.  It used four sound channels with four physical speakers intended to be positioned at the four corners of the listening space and each channel could reproduce a signal, in whole or in part, independent of the others.  It was briefly popular with manufacturers during the early 1970s, many of which attempted to position it as the successor to stereo as the default standard but consumers were never convinced and quadraphonic was a commercial failure, both because of technical issues and the multitude of implementations and incompatibilities between systems; many manufacturers built equipment to their own specifications and no standard was defined, a mistake not repeated a generation later with the CD (compact disc).  Nor was quadraphonic a bolt-on to existing equipment; it required new, more expensive hardware.

Quadraphonic audio reproduction from vinyl was patchy and manufacturers used different systems to work around the problems but few were successful and the physical wear of vinyl tended always to diminish the quality.  Tape systems also existed, capable of playing four or eight discrete channels and released in reel-to-reel and 8-track cartridge formats, the former more robust but never suited to the needs of mass-market consumers.  The rise of home theatre products in the late 1990s resurrected interest in multi-channel audio, now called “surround sound” and most often implemented in the six speaker 5.1 standard.  Modern electronics and the elimination of vinyl and tape as storage media allowed engineers to solve the problems which beset quadraphonic but there remain audiophiles who insist, under perfect conditions, quadraphonic remains the superior form of audio transmission for the human ear.

Highway Hi-Fi record player in 1956 Dodge.

First commercially available in 1965, the eight-track cartridge format (which would later become the evil henchman of quadraphonic) convinced manufacturers it was the next big thing and they rushed to mass-production and one genuine reason for the appeal was that the 8-track cartridge was the first device which was practical for use as in-car entertainment.  During the 1950s, the US car industry had offered the option of record players, neatly integrated into the dashboard and in the relatively compact space of a vehicle's interior, the sound quality could be surprisingly high.  Although not obviously designed with acoustic properties optimized for music, the combination of parallel flat surfaces, a low ceiling and much soft, sound absorbing material did much to compensate for the small size and range offered by the speakers.  However, although they worked well when sitting still in showroom or in certain vehicles, on the road things could be different.  The records (the same size as the classic 7 inch (180 mm) 45 rpm "singles") played by means of a stylus (usually called "the needle") which physically traced the grooves etched into the plastic disks rotating at 16.66 rpm which, combined with an etching technique called "ultra micro-grooving" meant the some 45 minutes of music were available, a considerable advance on the 4-5 minutes of the standard single.  The pressings were also thicker than other records, better to resist the high temperatures caused by heat-soak from the engine and the environment although, in places like Arizona, warping was soon reported.  To keep the stylus in the track, the units were fitted with a shock-absorbing, spring enclosure and a counterweighted needle arm.  Improbably, in testing, the system performed faultlessly even under the most adverse road conditions so the designers presented the product for corporate approval.  At that point there was a delay because the designers worked for the Colombia Broadcasting Corporation (CBS) which had affiliations with thousands of radio stations all over the country and no wish to cannibalize their own markets; if people could play records in their cars, the huge income stream CBS gained from advertising would be threatened as drivers tuned out.  The proposal was rejected.

Highway Hi-Fi record player in 1956 Plymouth.

Discouraged but not deterred, the engineers went to Detroit and demonstrated the players to Chrysler which had their test-drivers subject the test vehicles to pot-holes, railway tracks and rolling undulations.  The players again performed faultlessly and Chrysler, always looking for some novelty, placed an order for 18,000, a lucrative lure which convinced even CBS to authorize production, their enthusiasm made all the greater by the proprietary format of the disks which meant CBS would be the exclusive source.  So, late in 1956, Chrysler announced the option of "Highway Hi-Fi", a factory-installed record player mounted under the car's dashboard at a cost of (US$200 (some US$1750 in 2023 terms)).  Highway Hi-Fi came with six disks, the content of which reflected the reactionary tastes of CBS executives and their desire to ensure people still got their popular music from radio stations but the market response was positive, Chrysler selling almost 4000 of the things in their first year, the early adopters adopting with their usual alacrity.

The second generation of players used standard 45 rpm singles: Austin A55 Farina (left) and Beatle (lead guitarist) George Harrison's (1943–2001) Jaguar E-Type (right).  These two users presumably listened to different music although the player hardware was the same.  All four Beetles had the players fitted in their cars and Harrison is pictured here stocking his 14-disk stack. 

At that point, problems surfaced.  Tested exclusively in softly-sprung, luxury cars on CBS's and Chrysler's executive fleets, the Highway Hi-Fi had to some extent been isolated from the vicissitudes of the road but when fitted to cheaper models with nothing like the same degree of isolation, the styluses indeed jumped around and complaints flowed, something not helped by dealers and mechanics not being trained in their maintenance; even to audio shops the unique mechanism was a mystery.  Word spread, sales collapsed and quietly the the option was withdrawn in 1957.  The idea however didn't die and by the early 1960s, others had entered the field and solved most of the problems, disks now upside-down which made maintaining contact simpler and now standard 45 rpm records could be used, meaning unlimited content and the inherent limitation of the 4 minute playing time was overcome with the use of a 14-disk stacker, anticipating the approach taken with CDs three decades later.  Chrysler tried again by the market was now wary and the option was again soon dropped.

1966 Ford Mustang with factory-fitted 8-track player.

Clearly though, there was demand for in-car entertainment, the content of which was not dictated by radio station programme directors and for many there were the additional attractions of not having to endure listening either to advertising or DJs, as inane then as now.  It was obvious to all tape offered possibilities but although magnetic tape recorders had appeared as early as 1930s, they were bulky, fragile complicated and expensive, all factors which mitigated against their use as a consumer product fitted to a car.  Attention was thus devoted to reducing size and complexity so the tape could be installed in a removable cartridge and by 1963, a consortium including, inter alia, Lear, RCA, Ford & Ampex had perfected 8-track tape which was small, simple, durable and able to store over an hour of music.  Indeed, so good was the standard of reproduction that to take advantage of it, it had to be connected to high quality speakers with wiring just as good, something which limited the initial adoption to manufacturers such as Rolls-Royce and Cadillac or the more expensive ranges of others although Ford's supporting gesture late in 1965 of offering the option on all models was soon emulated.  Economies of scale soon worked its usual wonders and the 8-track player became an industry standard, available even in cheaper models and as an after-market accessory, some speculating the format might replace LP records in the home.

Lindsay Lohan's A Little More Personal (Raw) as it would have appeared if released in the 8-Track format.

That never happened although the home units were widely available and by the late 1960s, the 8-track was a big seller for all purposes where portability was needed.  It maintained this position until the early 1970s when, with remarkable suddenness, it was supplanted the the cassette, a design dating from 1962 which had been smaller and cheaper but also inferior in sound delivery and without the broad content offered by the 8-track supply system.  That all changed by 1970 and from that point the 8-track was in decline, reduced to a niche by late in the decade, the CD in the 1980s the final nail in the coffin although it did for a while retain an allure, Jensen specifying an expensive Lear 8-track for the Interceptor SP in 1971, despite consumer reports at the time confirming cassettes were now a better choice.  The market preferring the cheaper and conveniently smaller cassette tapes meant warehouses were soon full of 8-track players and buyers were scarce.  In Australia, GMH (General Motor Holden) by 1975 had nearly a thousand in the inventory which also bulged with 600-odd Monaro body-shells, neither of which were attracting customers.  Fortunately, GMH was well-acquainted with the concept of the "parts-bin special" whereby old, unsaleable items are bundled together and sold at what appears a discount, based for advertising purposes on a book-value retail price there’s no longer any chance of realizing.

1976 Holden HX LE

Thus created was the high-priced, limited edition LE (not badged as a Monaro although all seem still to use the name), in metallic crimson with gold pin striping, fake (plastic) aluminium wheels, fake (plastic) burl walnut trim and crushed velour (polyester) upholstery; in the 1970s, this was tasteful.  Not designed for the purpose, the eight-track cartridge player crudely was bolted to the console but five-hundred and eighty LEs were made, GMH pleasantly surprised at how quickly they sold.  When new, they listed at Aus$11,500, a pleasingly profitable premium of some 35% above the unwanted vehicle on which it was based.  These days, examples are advertised for sale for (Aus$) six-figure sums.  Those who now buy a LE do so for reasons other than specific-performance.  Although of compact size (in US terms) and fitted with a 308 cubic inch (5.0 litre) V8, it could achieve barely 110 mph (175 km/h), acceleration was lethargic by earlier and (much) later standards yet fuel consumption was high; slow and thirsty the price to be paid for the early implementations of the emission control devices bolted to engines designed during more toxic times.      

1971 Holden HQ Monaro LS 350

The overwrought and bling-laden Holden HX typified the tendency during the 1970s and of US manufacturers and their colonial off-shoots to take an elegant design and, with a heavy-handed re-style, distort it into something ugly.  A preview of the later “malaise era” (so named in the US for many reasons), it was rare for a facelift to improve the original.  The 1971 HQ Holden was admired for an austerity of line and fine detailing; what followed over three subsequent generations lacked that restraint.

Wednesday, January 12, 2022

Acid

Acid (pronounced as-id)

(1) In chemistry, a compound usually having a sour taste and capable of neutralizing alkalis and reddening blue litmus paper, containing hydrogen that can be replaced by a metal or an electropositive group to form a salt, or containing an atom that can accept a pair of electrons from a base. Acids are proton donors that yield hydronium ions in water solution, or electron-pair acceptors that combine with electron-pair donors or bases; having a pH value of less than 7.

(2) In chemistry, any compound which easily donates protons (a Brønsted acid); any of a class of water-soluble compounds, having sour taste, that turn blue litmus red, and react with some metals to liberate hydrogen, and with bases to form salts; any compound that can accept a pair of electrons to form a covalent bond (a Lewis acid).

(3) A substance sour, sharp, or biting to the taste; tart; having the taste of vinegar.

(4) Something, as a remark or piece of writing, that is sharp, sour, or ill-natured.

(5) A slang term for the hallucinogenic drug Lysergic acid diethylamide (LSD).

(6) In metallurgy, noting, pertaining to, or made by a process in which the lining of the furnace, or the slag that is present; functions as an acid in high-temperature reactions in taking electrons from oxide ions: usually a siliceous material, as sand or ganister.

(7) Of or pertaining to an acid; acidic.

(8) In pop music, a genre that is a distortion (as if hallucinogenic) of an existing genre, as in acid house, acid jazz, acid rock etc.

1620-1630: From the French acide, from Latin acidus (sour, sharp, tart (and used also figuratively to suggest "disagreeable” etc)), adjective of state from acere (to be sour, be sharp) and akin to ācer (sharp) & acētum (vinegar), from aceō (I am sour); doublet of agita.  Root was the primitive Indo-European ak (be sharp, rise (out) to a point, pierce).

The figurative use (sour-tempered; acerbic) in English dates from 1775 and came to be applied to intense colors after 1916.  The process of the acid dye was invented in 1888 and used an acid bath. The “acid test” is American English from 1881, originally a quick way to distinguish gold from similar metals by application of nitric acid, it came to be used figuratively (and not always accurately) in the same senses as “litmus test”.  The “Acid drop”, a kind of hard sugar candy flavored with tartaric acid, was first sold in 1835, the noun “drop” applied in the sense of a lozenge.  The noun appeared in the 1690s, derived from the adjective and was originally applied (rather loosely) to just about any substance tasting like vinegar; the more precise parameters defined only in the early eighteenth century as the techniques of modern chemistry came to be refined.  In the chemical sense, the antonym is alkaline.  The term “acid rain” (highly acidic rain caused by atmospheric pollution) was in 1872 coined by Scottish chemist (Robert) Angus Smith (1817–1884) although it wouldn’t be for another hundred years before if came into general use.  Diana, Princess of Wales (1961–1997) coined a nickname for her step-mother, Raine Spencer (1929-2016): Acid Raine.  

Acid as a slang term for the hallucinogenic drug Lysergic acid diethylamide (LSD) dates from 1966.  From the same year “acid rock” was originally a descriptor applied to music performed by those who were tripping on LSD (or what they sounded like suggested they might be) but, as acid rockers, soon applied equally to the audience.  The adjective before long was bolted onto a wide variety of pop music (acid jazz, acid folk etc), acid house from 1988 probably the most enduring as a marketing term. 

LSD-25 Auto.

In an example of cross-breeding in marketing,"LSD-25 Auto" is a strain of weed.  The retailers recommend LSD-25 Auto to those who “love purple strains”, praising her “tightly packed trichomes”… “clustered around the hypnotic purple shining buds that have a stacked and long characteristic”.  Bag appeal” is said to be “on the next level” and able to “blast you into another dimension and keep you there”.  Being “mind-bending and certainly on the trippy side”, she’s said to be “best suited for smokers with a high tolerance to cerebral roller coasters and those who enjoy high concentration levels and spurts of creativity”.  For those still unsure, they caution that “novice smokers should take in moderation”.

Cutaway drawing of limited slip differential (LSD).

LSD is also the abbreviation for the limited slip differential, a device used in motor vehicles which allows a differential’s two output shafts to rotate at different speeds within a defined permissible difference in speed.  LSDs are used to improve traction under extreme conditions and the usual slang is “slippery-diff”.  LSD was also the historic abbreviation for the currency denominations used by UK prior to the decimalization of Sterling in 1971.  Although pre-1971 Sterling (based on there being 12 pennies to the shilling and 20 shillings to the pound) also used guineas, half crowns, threepenny bits, sixpences and florins, LSD referenced just the base units: pounds, shillings and pence.  The abbreviation LSD dates from Ancient Rome when a pound of silver was divided into 240 pence (or denarius) and the Latin currency denominations were librae, solidi, and denarii.  In veterinary science, LSD is also the standard abbreviation for lumpy skin disease, a viral disease of cattle and water buffalo.

Lindsay Lohan in Peter Thomas Roth’s campaign promoting Water Drench Hyaluronic Cloud Hydra-Gel Eye Patches.

The active ingredient in the patches is hyaluronic acid, a gooey, slippery substance produced naturally throughout the body and at its highest concentration in the eyes, joints and skin.  Best visualized as a lubricant, it works by providing a fluid cushion between tissues which would otherwise grind against each other.  As a lubricant, hyaluronic acid has remarkable properties, one teaspoon of the stuff able to absorb and retain some 6 US gallons (22¾ litres) of water, a reason why it’s used in the treatment of dry eyes and is a popular additive in in moisturizing creams, lotions, ointments and serums.  Hyaluronic acid is often produced by fermenting certain types of bacteria (rooster combs (the red, Mohawk-like growth on top of a rooster’s head and face) a common source) something the beauty industry dwells on less than the use to enhance the way skin stretches and flexes, reducing wrinkles.  It said also to be helpful in wound healing and the reduction in scarring.

Because of the popular association science fiction and gaming with toxic, flesh dissolving fluids (sometimes flowing through the veins of aliens) the word “acid” evokes horror in many but the body naturally produces many acids and it depends on these interacting with everything else to ensure good health and acids in many forms are in every diet.  An apple (a typical example containing up to 300 chemicals) for example includes pantothenic acid (B5), citric acid, tartaric acid & acetic acid while its taste depends on the concentration of malic acid.  Pantothenic is a combination of pantoic acid and β-alanine, the name pantohenic from the Greek πάντοθεν (pantothen) (from everywhere), the name chosen by chemists because, at least in tiny quantities, it’s present in almost all foods.  Familiar too is the pain-killer aspirin, now taken by many in low-dose form (100 mg or 1½ grains), a regime first recommended as a blood-thinner for those with certain risk factors for heart disease but later adopted by those impressed with the apparent protection offered against many internal cancers.  To a chemist, what we call the non-steroidal anti-inflammatory drug aspirin is acetylsalicylic acid (usually pronounced uh-seet-l-sal-uh-sil-ik as-id).  

Lysergic acid diethylamide

LSD, known colloquially as acid, is a drug known for its psychological effects. This includes altered awareness of surroundings, perceptions, and feelings as well as sensations and images that seem real though they are not.  It’s thus most often described as a hallucinogenic and the one which first generated a moral-panic although there has never been any evidence to support the stories which circulated telling cautionary tales of users leaping to their deaths from tall buildings, thinking themselves able to fly.  The urban myths persist to this day.

LSD was created in Basel in November, 1938 by Swiss chemist Albert Hofmann (1906–2008).  Dr Hofmann synthesized LSD after examining the constituents of the well-known medicinal plant Drimia maritima (squill) and the fungus ergot, the breakthrough moment apparently his understanding of the chemical structure of the squill's Scilla glycosides but the famous properties were discovered only serendipitously, his pharmaceutical research for a unrelated purpose.  It wasn't until 1943 that Dr Hofmann conducted any research on the possibilities LSD might offer using what he then regarded as side-effects.  In a long-known scientific tradition, he tested it on himself, thus enjoying the first acid-trip.

Having no bad trips, he continued the research and LSD (acronym for the German Lyserg-säure-diäthylamid) was in 1947 introduced as a commercial medication under the trade-name Delysid and intended for various psychiatric uses.  In the 1950s, the CIA thought the drug might be useful for mind control and chemical warfare, their tests conducted on young servicemen and students, usually without anything even close to informed consent.  Its possibilities interested psychiatrists and it was a popular subject in experimental research, the design of many of which would today appall ethics committees and terrify the lawyers.

President Richard Nixon (1913-1994; US president 1969-1974) explaining to congress aspects the message sent to the Congress on 17 June 1971, requesting the appropriation of an additional US$155 million for a “war on drugs”.  Egil Krogh (1939-2020 left) was deputy director of the Domestic Council and Dr Jerome Jaffe (b 1933, right) was hired to lead a new drug strategy and was usually referred to as Nixon’s “drugs tsar”.  Egil Krogh was later jailed for his involvement in the Watergate affair.

The subsequent recreational use in the Western world, an outgrowth of the 1960s counterculture, resulted in its worldwide prohibition in 1971, one of the most obvious casualties of the Nixon administration’s “war on drugs” which has around the world been for fifty-odd years waged with many consequences but little apparent effect on the demand for drugs, supply now at historically high levels, outpacing the increase in population.  Fifty years on, LSD remains popular though the extent of its use varies according to supply which tends to be dictated more by the economics of production and distribution than demand, the illicit drug business really preferring other substances because LSD is not addictive.  Of late there’s been much renewed interest in the possibilities offered by therapeutic hallucinogenics, the encouraging findings in DMT, LSD, mescaline & psilocybin research drawing in venture capital, the odd start-up picking up not only where things were left off in 1971 but working with more recently synthesised compounds.  Their difficulties are less scientific than regulatory.

Notable moments in Acid Rock

Todd Rundgren: A Wizard, a True Star (1973).

It’s not known if most listeners recovered from this but Todd Rundgren probably never did, his subsequent output so discursive that the many audiences he sought and sometimes gained never coalesced into a consistent following.   A Wizard, a True Star is there to be enjoyed as his psychedelic phase; just don’t expect more of the same.

Grateful Dead: Aoxomoxoa (1969).

Anthem of the Sun (1968) cast such a shadow that few dead heads list Aoxomoxoa as the band’s finest but none deny it’s the most psychedelic the Dead ever got in the studio.  The hippie-dippy vibe is of course more on display on many of the live releases (bootlegs and otherwise) but on Aoxomoxoa there are enough of the long, circular guitar lines for any tripper to keep tripping.  Unlike some of the European electronica which would follow, the Dead sound best through speakers rather than headphones but, at the time, the effect of Quadraphonic divided opinion.

The Jimi Hendrix Experience: Electric Ladyland (1968).

Not all of Electric Ladyland was as psychedelic as the reputation suggests but, spread over two records, there was room to move and psychedelia does at least tinge much of the blues for which this is remembered.  Some trippers however resist the epic length Voodoo Chile and go straight to side three of the original vinyl, setting the turntable to repeat.

Spirit: Twelve Dreams of Dr Sardonicus (1970).

Although not released until the era’s historic moment had passed with the implosion of the San Francisco ecosystem which fed the beast, Twelve Dreams Of Dr Sardonicus is the retrospective encapsulation of the psychedelic and is Spirit’s masterpiece.  Lyrically one long, strange trip, it’s also musically playful, mixing (rather than fusing) the most clichéd of the motifs of jazz, pop & rock.  This is acid rock’s period piece.

Pink Floyd: More (1969).

So much has Dark Side of the Moon (1973) loomed over Pink Floyd that their early work is neglected by all but a few.  In some cases the indifference is not undeserved but, influenced by the late Syd Barrett (1946-2006), before they were a staple of FM radio, Pink Floyd were certainly somewhere on the psychedelic spectrum and while The Piper At The Gates Of Dawn (1967) hints at it, their work in a trilogy of film soundtracks, More (1969), Zabriskie Point (1970) & Obscured by Clouds (1972) tracks the path of acid-rock.  The best approach is said to be to watch Zabriskie Point with the sound turned down while the album plays on repeat and a true aficionado will drop some acid a few minutes before putting on the headphones.



Sheryl Crow: There goes the neighborhood

Hey let's party
Let's get down
Let's turn the radio on
This is the meltdown
Get out the camera
Take a picture
The drag queens and the freaks
Are all out on the town
And cowboy Jane's in bed
Nursing a swollen head
 
Sunshine Sally and Peter Ustanov
Don't like the scene any how
I dropped acid on a Saturday night
Just to see what the fuss was about
Now there goes the neighborhood
 
The photo chick made to look sickly
Is standing in her panties in the shower
She plays the guitar in the bathroom
While the police dust her mother's plastic flowers
And Schoolboy John's in jail
Making a killing through the U.S. mail
 
Sunshine Sally and Peter Ustanov
Don't like the scene any how
I dropped acid on a Saturday night
Just to see what the fuss was about
Now there goes the neighborhood
 
This is the movie of the screenplay
Of the book about a girl who meets a junkie.
The messenger gets shot down
Just for carrying the message to a flunkie.
We can't be certain who the villans are 'cuz everyone's so pretty
But the afterparty's sure to be a wing-ding as it moves into your city
 
Sunshine Sally and Peter Ustanov
Don't like the scene any how
I dropped acid on a Saturday night
Just to see what the stink was about
Now there goes the neighbourhood.

Monday, July 1, 2024

Discreet & Discrete

Discreet (pronounced dih-skreet)

(1) Judicious in conduct or speech, especially with regard to respecting privacy or maintaining silence about delicate matters; prudent; circumspect.

(2) Showing prudence and circumspection; decorous.

(3) Modestly unobtrusive; unostentatious.

1325–1375: From the Middle English discret, from the Anglo-French & Old French discret (prudent, discerning), from the Medieval Latin discrētus (separated), past participle of discernere (to discern), the construct being dis- + crē- (separate, distinguish (variant stem of cernere)) + -tus, the Latin past participle suffix.  The dis prefix was from the Middle English dis-, from the Old French des from the Latin dis, from the proto-Italic dwis, from the primitive Indo-European dwís and cognate with the Ancient Greek δίς (dís) and the Sanskrit द्विस् (dvis).  It was applied variously as an intensifier of words with negative valence and to render the senses “incorrect”, “to fail (to)”, “not” & “against”.  In Modern English, the rules applying to the dis prefix vary and when attached to a verbal root, prefixes often change the first vowel (whether initial or preceded by a consonant/consonant cluster) of that verb. These phonological changes took place in Latin and usually do not apply to words created (as in Modern Latin) from Latin components since the language was classified as “dead”.  The combination of prefix and following vowel did not always yield the same change and these changes in vowels are not necessarily particular to being prefixed with dis (ie other prefixes sometimes cause the same vowel change (con; ex)).  The Latin suffix –tus was from the Proto-Italic -tos, from the primitive Indo-European -tós (the suffix creating verbal adjectives) and may be compared to the Proto-Slavic –tъ and Proto-Germanic –daz & -taz.  It was used to form the past participle of verbs and adjectives having the sense "provided with".  Latin scholars caution the correct use of the –tus suffix is technically demanding with a myriad of rules to be followed and, in use, even the pronunciation used in Ecclesiastical Latin could vary.  Discreet, discreeter, discreetest & discretionary are adjectives, discreetness & discretion are nouns and discreetly is an adverb; the noun plural is discretions.  Such is the human condition, the derived form "indiscretion" is in frequent use.

Discrete (pronounced dih-skreet)

(1) Apart or detached from others; separate; non-continuous; distinct; that which can be perceived individually and not as connected to, or part of something else.

(2) Consisting of or characterized by distinct or individual parts; discontinuous; that which can be perceived individually, not as connected to, or part of, something else.

(3) In mathematics, of a topology or topological space, having the property that every subset is an open set; defined only for an isolated set of points; using only arithmetic and algebra; not involving calculus.

(4) In mathematics, consisting of or permitting only distinct values drawn from a finite, countable set.

(5) In statistics (of a variable), having consecutive values not so infinitesimally close, so that its analysis requires summation rather than integration.

(6) In electrical engineering, having separate electronic components (diodes, transistors, resisters etc) as opposed to integrated circuitry (IC).

(7) In audio engineering, having separate and independent channels of audio, as opposed to multiplexed stereo, quadraphonic (also as quadrasonic) or other multi-channel sound.

(8) In linguistics, disjunctive, containing a disjunctive or discretive clause.

(9) In angelology, the technical description of the hierarchies and orders of angels.

1350–1400: Middle English from the Latin discrētus (separated; set apart) past participle of discernō (divide), the construct being dis- + cernō (sift); a doublet of discreet.  The Middle English adoption came via the Old French discret.  The common antonym is indiscrete (never hyphenated) but nondiscrete (also non-discrete), while synonymous in general used, is often used with specific meanings in mathematics & statistics.  Discrete is an adjective, discreteness is a noun and discretely is an adverb.  

Strange words

An etymological tangle, it was the influence of the Middle French discret (prudent, discerning) which saw discreet evolve to mean “wise person” in Anglo-French.  The Latin source was discrētus (past participle of the verb discernere (to discern; to separate, distinguish, mark off, show differences between)) and in post-Classical Latin discrētus also acquired the sense “prudent, wise,” possibly arising from association with the noun discrētiō, which shows a similar semantic development: physical separation, to discernment, to capacity to discern, the the notion of a "discreet person" being able to "pick" their way, setting "apart" the good from the bad, (dis- being "apart" & cerno "pick").

Discrete (apart or detached from others; separate; distinct) was originally a spelling doublet of discreet, sharing meanings, both derived from the same Latin source.  The spelling discrete is closer in form to the Latin discrētus and was probably a deliberate attempt to differentiate "discreet" from "discrete" (a courtesy to users English doesn't always extend) and one has always been more prolific than the other, dictionaries for centuries tending to offer some five times the citations for “prudent, circumspect” compared with the sense “separate or distinct” although the history of the latter is long in statistics, angelology, astronomy, and mathematics.  It wasn’t until the late sixteenth century that discrete became restricted to the now familiar meanings, leaving the spelling discreet to predominate in its own use.  In a way not uncommon in English, pre-modern spellings proliferated: discreyt, discrite, discreit, discreete and others existed but, by the late sixteenth century, the standard meanings became discrete in the sense of “individual” and discreet in the sense of “tactful”.  Had the usual convention been followed it would have been the other way around because in English the Latin ending –etus usually becomes –ete.  Even into the mid-twentieth century, there were style & usage guides which recommended different pronunciations for discrete & discreet the former accented dĭ'-krē’t rather than dĭs-krē’t, the rationale being it was both “natural in English accentuation” (the example of the adjectival use of “concrete” cited) and helpful in distinguishing the word from “discreet”.  The modern practice however is to use the same pronunciation for both, leaving the labor of differentiation to context.

Artistic angelology: The Assumption of the Virgin (1475-1476), by Francesco Botticini (1446–1498), tempera on wood panel, National Gallery, London.  Commissioned as the altarpiece for a Florentine church, it portrays Mary's assumption and shows the discrete three hierarchies and nine orders of angels.

The noun discretion means (1) the power or right to decide or act according to one's own judgment; freedom of judgment or choice and (2) the quality of being discreet, especially with reference to one's own actions or speech; prudence or decorum.  Discretion dates from 1250–1300 and was from the Middle English discrecioun, from the Anglo-French & Old French discrecion, from the Late Latin discrētiōnem-(stem of discrētiō (separation)).  The special use in English law as the “age of discretion” began in the mid-fourteenth century as dyscrecyounne (ability to perceive and understand) meaning one was deemed to have attained “moral discernment, ability to distinguish right from wrong”.  It thus implied “prudence, sagacity regarding one's conduct”.  The meanings of the later forms came from the Medieval Latin (discernment, power to make distinctions), which evolved from the use in Classical Latin (separation, distinction).

The Age of Discretion

The familiar phrase “at one’s discretion seems not to have been in use until the 1570s although “in one's discretion” was documented by the late fourteenth century.  The use in English common law meaning “power to decide or judge; the power of acting according to one's own judgment” was reflected in the legal principle “the age of discretion which was part of law since the late fourteenth century when the age was deemed to be fourteen years, the age William Shakespeare (1564–1616) chose for the star-cross'd lovers in Romeo and Juliet (1597).

Historically, the “age of discretion” referred to the age at which a child was considered to be capable of making certain decisions and understanding the consequences of their actions.  Typically, was typically around seven years old, the point at which a child was deemed to have enough understanding to be responsible for certain actions, such as committing a crime or making religious decisions.  Gradually, the age crept up, especially as it applied to doli incapax (the age under which a child was presumed incapable of committing a crime) until it became established law a child between seven and fourteen was presumed not to have criminal intent unless it could be proven otherwise, the evidential onus of proof resting wholly with the prosecutor (almost always the Crown (ie some agent of the state)).  The generalized idea of an “age of discretion” influenced later developments in law such as the age of criminal responsibility, at which one could enter into legally enforceable contracts, enjoy a testamentary capacity or (lawfully) have sex.  Between jurisdictions the relevant age for this and that does vary and changes are not always without controversy: under the Raj, when Lord Lansdowne (1845–1927; Viceroy of India 1888-1894) raised the age of sexual consent for girls from ten to twelve, the objections from men united the castes like few other issues.

Lindsay Lohan and her lawyer in court, Los Angeles, December 2011.

For their purposes, the Church preferred seven and habitually declared children this age were capable of making their own decisions regarding religious practices, such as confession and communion and the phrase “give me the child until the age of seven and I will give you the man” is attributed usually to the Spanish priest Saint Ignatius of Loyola 1491-1556) who founded the religious order of the Society of Jesus (the Jesuits).  It’s no longer thought wise to leave children alone with priests but the social media platforms well-understood the importance of gaining young converts and for years did nothing to try to enforce their minimum age requirements for account creation.  The consequences of this have of late become understood and the debate about the wisdom of “giving children access to the internet” is now being framed as the more ominous “giving the internet access to children.

Discreet Allure: “Discreet” is here used in the sense of “modestly unobtrusive; unostentatious” and was in reference to the displayed clothing lines which were designed to be acceptable (halal (حلال)) under the Sharia (شَرِيعَة).  Lindsay Lohan at London Modern Fashion Week, February 2018.