Satu ujikaji perakam pita awal bukan magnet yang dipatenkan pada tahun 1886 oleh Volta Makmal Alexander Graham Bell.

Varian terawal: perakam jalur lilin bukan bermagnet

Perakam pita audio yang paling awal diketahui versi bukan bermagnet, bukan elektrik yang dicipta oleh makmal Volta Alexander Graham Bell dan dipatenkan pada tahun 1886 (U.S. Patent 341,214 ).[1] Ia menggunakan satu jalur kertas lilin 16/3 inci lebar (4.8 mm) yang dilindungi dengan mencelup ia dalam larutan lilin lebah dan parafin dan kemudian mempunyai satu sisi yang dikikis licin, sementara sisi yang lain dibenarkan mengeras. Mesin ini dibina dengan menggunakan kayu dan logam yang kukuh, dan berkuasa tangan melalui tombol yang dilekatkan pada roda tenaga . Jalur lilin melalui satu gelendung satu per lapan inci mengelilingi pinggir takal (dengan panduan bebibir) yang dipasang pada takal-V pada aci menegak utama, di mana ia bertembung dengan sama ada stylus perakam atau pemain balik. Pita itu kemudiannya digulung pada gelendong lain. Stylus perakam yang tajam, digetarkan oleh diafragma mika bergetar, mengukir lilin dari jalur. Dalam mod main balik, stylus tumpul, dipasang longgar, dilekatkan pada diafragma getah, membawa bunyi yang dihasilkan semula melalui tiub telinga kepada pendengar itu.[1]

Kedua-dua kepala rakaman dan main semula, dipasang silang-seli pada dua tiang, yang boleh diselaraskan secara menegak agar beberapa rakaman boleh dipotong pada jalur 16/3 inci lebar (4.8 mm) yang sama. Walaupun mesin ini tidak pernah dibangunkan secara komersial, ia adalah satu moyang menarik bagi perakam pita magnetik moden yang menyerupai dari segi reka bentuknya. Pita dan mesin yang dibuat oleh syarikat-syarikat sekutu Bell, diperiksa di salah sebuah Institusi muzium Smithsonian, menjadi rapuh, dan kertas gulungan yang berat meleding. Kepala main balik mesin juga hilang. Jika tidak, dengan beberapa pemulihan, ia boleh dipulihkan kembali berfungsi.[1]

Tolong bantu menterjemahkan sebahagian rencana ini. Rencana ini memerlukan kemaskini dalam Bahasa Melayu piawai Dewan Bahasa dan Pustaka. Sila membantu, bahan-bahan boleh didapati di Perakam pita (Inggeris). Jika anda ingin menilai rencana ini, anda mungkin mahu menyemak di terjemahan Google. Walau bagaimanapun, jangan menambah terjemahan automatik kepada rencana, kerana ini biasanya mempunyai kualiti yang sangat teruk. Sumber-sumber bantuan: Pusat Rujukan Persuratan Melayu.

Photoelectric variant

In 1932, after six years of developmental work, Merle Duston, a Detroit radio engineer, created a tape recorder that used a low-cost chemically treated paper tape, capable of recording both sounds and voice. During the recording process, the tape moved through a pair of electrodes which immediately imprinted the modulated sound signals as visible black stripes into the paper tape's surface. The sound track could be immediately replayed from the same recorder unit, which also contained photoelectric sensors, somewhat similar to the various motion picture sound-on-film technologies of the era.[2][3]

On 13 August 1931, Duston filed USPTO Patent Application #556,743 for "Method Of And Apparatus For Electrically Recording And Reproducing Sound And Other Vibrations", and which was renewed in 1934.[4][5]

Magnetic recording

Magnetic recording was conceived as early as 1877 by the American engineer Oberlin Smith and demonstrated in practice in 1898 by Danish engineer Valdemar Poulsen. Analog magnetic wire recording, and its successor, magnetic tape recording, involve the use of a magnetizable medium which moves with a constant speed past a recording head. An electrical signal, which is analogous to the sound that is to be recorded, is fed to the recording head, inducing a pattern of magnetization similar to the signal. A playback head can then pick up the changes in magnetic field from the tape and convert it into an electrical signal.

Steel wire magnetic recorder variant

Magnetic wire recorder, invented by Valdemar Poulsen, 1898. It is exhibited at Brede works Industrial Museum, Lyngby, Denmark.

The first wire recorder was the Valdemar Poulsen Telegraphone of the late 1890s, and wire recorders for law/office dictation and telephone recording were made almost continuously by various companies (mainly the American Telegraphone Company) through the 1920s and 1930s. These devices were mostly sold as consumer technologies after World War II.

Widespread use of the wire recording device occurred within the decades spanning from 1940 until 1960, following the development of inexpensive designs licensed internationally by the Brush Development Company of Cleveland, Ohio and the Armour Research Foundation of the Armour Institute of Technology (later Illinois Institute of Technology).[petikan diperlukan] These two organizations licensed dozens of manufacturers in the U.S., Japan, and Europe.[petikan diperlukan] Wire was also used as a recording medium in black box voice recorders for aviation in the 1950s.

Consumer wire recorders were marketed for home entertainment or as an inexpensive substitute for commercial office dictation recorders, but the development of consumer magnetic tape recorders starting in 1946, with the BK 401 Soundmirror,using paper-based tape,[6] quickly drove wire recorders from the market.[petikan diperlukan]

Early steel tape recorders

In 1924 a German engineer, Dr. Kurt Stille, developed the Poulsen wire recorder as a dictating machine. The following year a fellow German Louis Blattner, working in Britain, licensed Stille's device and started work on the developments which produced the Blattnerphone,[7] now using steel tape.

Blattnerphone steel tape recorder at BBC studios, London, 1937

The BBC installed a Blattnerphone at Avenue House in September 1930 for tests, and used it to record King George V's speech at the opening of the India Round Table Conference on 12 November 1930. Though not considered suitable for music the machine continued in use and was moved to Broadcasting House in March 1932, a second machine also being installed.

The tape was 6mm wide and 0.08mm thick, travelling at 5 feet per second; the recording time was 20 minutes.

In September 1932 a new model was installed, using 3mm tape with a recording time of 32 minutes.

In 1933 the Marconi Company purchased the rights to the Blattnerphone, and newly developed Marconi-Stille recorders were installed in the BBC's Maida Vale Studios in March 1935.[8] The quality was slightly improved, though it still tended to be obvious that one was listening to a recording, as was the reliability. A reservoir system containing a loop of tape helped to stabilize the speed (there was also a smaller one just before the heads). The tape was 3mm wide and travelled at 1.5 metres/second. By September there were three recording rooms, each with two machines.

They were hardly easy to handle. The spools were heavy (and expensive) and the tape has been described as being like a travelling razor blade. The tape was liable to snap, particularly at joints, which at that speed could rapidly cover the floor with loops of the sharp-edged tape. Rewinding was done at twice the speed of the recording.

However despite all this, the ability to make replayable recordings was extremely useful, and even with subsequent methods coming into use (direct-cut discs[9] and Philips-Miller optical film[10]) the Marconi-Stilles remained in use until the late 1940s.[11]

German developments

Magnetic tape recording as we know it today was developed in Germany during the 1930s at BASF (then part of the chemical giant IG Farben) and AEG in cooperation with the RRG. This was based on Fritz Pfleumer's 1928 invention of paper tape with oxide powder lacquered to it. The first practical tape recorder from AEG was the Magnetophon K1, demonstrated in Germany in 1935. Eduard Schüller of AEG built the recorders and developed a ring shaped recording and playback head. It replaced the needle shaped head which tended to shred the tape. Friedrich Matthias of IG Farben/BASF developed the recording tape, including the oxide, the binder, and the backing material. Walter Weber, working for Hans Joachim von Braunmühl at the RRG, discovered the AC biasing technique, which radically improved sound quality.[12]

Magnetophon from a German radio station in World War II..

During World War II, the Allies noticed that certain German officials were making radio broadcasts from multiple time zones almost simultaneously.[12] Analysts such as Richard H. Ranger believed that the broadcasts had to be transcriptions, but their audio quality was indistinguishable from that of a live broadcast[12] and their duration was far longer than was possible with 78 rpm discs. (The Allies were aware of the existence of the pre-war Magnetophon recorders, but not of the introduction of high-frequency bias and PVC-backed tape.)[13] In the final stages of the war in Europe, the Allied capture of a number of German Magnetophon recorders from Radio Luxembourg aroused great interest. These recorders incorporated all of the key technological features of modern analog magnetic recording and were the basis for future developments in the field.