SUMMARY / RELATED TOPICS

Dynamic range

Dynamic range is the ratio between the largest and smallest values that a certain quantity can assume. It is used in the context of signals, like sound and light, it is measured either as a ratio or as a base-10 or base-2 logarithmic value of the difference between the smallest and largest signal values. Electronically reproduced audio and video is processed to fit the original material with a wide dynamic range into a narrower recorded dynamic range that can more be stored and reproduced; the human senses of sight and hearing have a high dynamic range. However, a human cannot perform these feats of perception at both extremes of the scale at the same time; the human eye takes time to adjust to different light levels, its dynamic range in a given scene is quite limited due to optical glare. The instantaneous dynamic range of human audio perception is subject to masking so that, for example, a whisper cannot be heard in loud surroundings. A human is capable of hearing anything from a quiet murmur in a soundproofed room to the loudest heavy metal concert.

Such a difference can exceed 100 dB which represents a factor of 100,000 in amplitude and a factor 10,000,000,000 in power. The dynamic range of human hearing is 140 dB, varying with frequency, from the threshold of hearing to the threshold of pain; this wide dynamic range cannot be perceived all at once, however. A human can see objects in starlight or in bright sunlight though on a moonless night objects receive 1/1,000,000,000 of the illumination they would on a bright sunny day. In practice, it is difficult for humans to achieve the full dynamic experience using electronic equipment. For example, a good quality LCD has a dynamic range limited to around 1000:1, some of the latest CMOS image sensors now have measured dynamic ranges of about 23,000:1. Paper reflectance can produce a dynamic range of about 100:1. A professional video camera such as the Sony Digital Betacam achieves a dynamic range of greater than 90 dB in audio recording. Audio engineers use dynamic range to describe the ratio of the amplitude of the loudest possible undistorted signal to the noise floor, say of a microphone or loudspeaker.

Dynamic range is therefore the signal-to-noise ratio for the case where the signal is the loudest possible for the system. For example, if the ceiling of a device is 5 V and the noise floor is 10 µV the dynamic range is 500000:1, or 114 dB: 20 × log 10 ⁡ = 20 × log 10 ⁡ = 20 × 5.7 = 114 d B In digital audio theory the dynamic range is limited by quantization error. The maximum achievable dynamic range for a digital audio system with Q-bit uniform quantization is calculated as the ratio of the largest sine-wave rms to rms noise is: D R A D C = 20 × log 10 ⁡ = d B However, the usable dynamic range may be greater, as a properly dithered recording device can record signals well below the noise floor; the 16-bit compact disc has a theoretical undithered dynamic range of about 96 dB. Digital audio with undithered 20-bit quantization is theoretically capable of 120 dB dynamic range. 24-bit digital audio affords 144 dB dynamic range. Most Digital audio workstations process audio with 32-bit floating-point representation which affords higher dynamic range and so loss of dynamic range is no longer a concern in terms of digital audio processing.

Dynamic range limitations result from improper gain staging, recording technique including ambient noise and intentional application of dynamic range compression. Dynamic range in analog audio is the difference between low-level thermal noise in the electronic circuitry and high-level signal saturation resulting in increased distortion and, if pushed higher, clipping. Multiple noise processes determine the noise floor of a system. Noise can be picked up from microphone self-noise, preamp noise and interconnection noise, media noise, etc. Early 78 rpm phonograph discs had a dynamic range of up to 40 dB, soon reduced to 30 dB and worse due to wear from repeated play. Vinyl microgroove phonograph records yield 55-65 dB, though the first play of the higher-fidelity outer rings can achieve a dynamic range of 70 dB. German magnetic tape in 1941 was reported to have had a dynamic range of 60 dB, though modern day restoration experts of such tapes note 45-50 dB as the observed dynamic range. Ampex tape recorders in the 1950s achieved 60 dB in practical us

Chandragupta basadi

Chandragupta basadi is one of the smaller basadis located on the Chandragiri Hill in Sravanabelagola in the Indian state of Karnataka. The basadi consisted of three cells standing in a line and opening into a narrow passage; the basadi is southfacing and the cells on either side have small towers over them resembling the chole type. Subsequently, an ornamental doorway has been added in front with perforated stone screens at the sides; the screens are pierced with square openings are carved with minute sculptures, interpreted, in the light of Jaina tradition, as the scenes from the lives of the Srutakevali and Chandragupta Maurya. Some irregularity is observed in the alternate rows of the eastern screens owing to some misplacement. By replacing the topmost stone at the bottom and the bottom one at the top the rows regularity correspond with those of the western screen; the middle cell of this temple has the figure of Parshvanatha, the one to the right the figure of Padmavathi and the one to the left the figure of Kushmandini, all in a seated posture.

In the verandah there are standing figures of Dharanendra yaksha at the right end and Sarvahna yaksha at the left. The temple opens into the front hall which forms the entrance to the Kattale basadi. In this hall stands a figure of Kshetrapala opposite to the middle cell of the Chandragupta basadi; the outer walls are decorated with pilasters, niches, the heads and trunks of lions in pairs facing each other. Tradition says; the label dasoja occurring on one of the screens is undoubtedly the name of the sculptor who made the screens and the doorway. He is probably identical with the sculptor who carved some of the fine bracket images of the Chennakesava temple at Belur and therefore the period of the screens and the doorway would be about the middle of the 12th century A. D; the other parts of the building are some of the oldest on the hill going back to the ninth or tenth century A. D. Jainism in Karnataka

Amaryllis Garnett

Amaryllis Virginia Garnett was an English actress and diarist. Born in St Pancras, Garnett was the eldest of the four daughters of David and Angelica Garnett, her father was a writer, while her mother, an artist, was the daughter of Vanessa Bell and the painter Duncan Grant and a niece of the writer Virginia Woolf. Her other grandfather was Edward Garnett, a publisher and writer, while her great-grandparents included Constance Garnett, a prolific translator of Russian literature, Richard Garnett and librarian, Leslie Stephen and Julia Duckworth, a pre-Raphaelite artists' model and niece of the photographer Julia Margaret Cameron. In 1946 T. H. White, a friend of Amaryllis Garnett's parents, wrote his book Mistress Masham's Repose for her, which for White became the beginning of a new career as a children's writer. A biographer of White notes that in the book "Children are never told that their elders are better than they are or taught Algebra, just Oeconomy, Natural History, other subjects dealing with life, a situation which would doubtless have delighted Amaryllis Garnett."

The four sisters called their parents "Angelica" and "Bunny" and had a unconventional childhood. While the family was living at Hilton Hall, near St Ives, Henrietta and Fanny were all sent, a little improbably, to the co-educational Huntingdon Grammar School, where Amaryllis arrived at the age of eleven, they made few friends there, but took leading parts in school plays and were the most creative pupils. Meanwhile, at home there was a farm, with a herd of Jersey cows, an orchard, a swimming pool, a dovehouse. At the age of sixteen, Garnett went as a boarder to Cranborne Chase School trained for an acting career at a drama school in London. In 1967, Garnett joined the Royal Shakespeare Company; the same year, she had her first screen role in an ITV Play of the Week written by John Mortimer called A Choice of Kings. As an actress, she was taken up by Harold Pinter. Spotlight 1973 gave her height her eye colour as blue, her mother described her as "very beautiful and intelligent". In 1969, according to Frances Spalding, she was much admired by Cyril Connolly.

In her late twenties, Garnett was living on a houseboat on the River Thames, moored by Battersea Bridge at Chelsea, bought for her by her parents. However, her life was turbulent, the result of combining a high-spending lifestyle with having no income at all, she decided to give up acting and move to Morocco with a boyfriend, causing her father to complain "Surely she ought to get a job and get on with her profession!" At the age of 29, her life fell apart, in May 1973, while suffering from deep depression, she drowned in the river at Chelsea. Thought to be a case of suicide, it is possible that her death was an accident, she left behind a diary. Amaryllis Garnett on IMDb Amaryllis Garnet: Portrait of a girl reading, by Duncan Grant at artinfo.com Huntingdon school play – Amaryllis Garnett as Queen at huntingdon.ccan.co.uk