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Adictation machine is asound recording device most commonly used to recordspeech for playback or to be typed into print. It includesdigital voice recorders andtape recorder.
The name "Dictaphone" is atrademark of the company of the same name, but it has also become a common term for all dictation machines, as agenericized trademark.
Alexander Graham Bell and his two associates took Edison'stinfoil phonograph and modified it considerably to make it reproduce sound from wax instead of tinfoil. They began their work at Bell'sVolta Laboratory in Washington, D.C.In 1879, and continued until they were granted basic patents in 1886 for recording in wax.[1]
Thomas A. Edison hadinvented the phonograph in 1877, but the fame bestowed on him for this invention — sometimes called his most original — was not due to its efficiency. Recording with his tinfoil phonograph was too difficult to be practical, as the tinfoil tore easily, and even when thestylus was properly adjusted. Although Edison had hit upon the secret ofsound recording, immediately after his discovery he did not improve it, allegedly because of an agreement to spend the next five years developing theNew York City electric light and power systems.[1]
By 1881 the Volta associates had success in improving an Edison tinfoil machine to some extent. Wax was put in the grooves of the heavy iron cylinder, and no tinfoil was used. The basic distinction between the Edison's first phonograph patent, and the Bell and[Charles Sumner] Tainter patent of 1886 was the method of recording. Edison's method was to indent the sound waves on a piece of tinfoil, while Bell and Tainter's invention called for cutting, or 'engraving', the sound waves into a wax record with a sharp recording stylus.[1]
Among the later improvements by theVolta Associates, the Graphophone used a cutting stylus to create lateral zig-zag grooves of uniform depth into the wax-coated cardboard cylinders, rather than the up-downvertically-cut grooves of Edison's contemporary phonograph machine designs.[1][2]
Notably, Bell and Tainter developed wax-coated cardboard cylinders for theirrecord cylinders, instead of Edison's cast iron cylinder, covered with a removable film of tinfoil (the actual recording medium, which was prone to damage during installation or removal.[3] Tainter received a separate patent for a tube assembly machine to automatically produce the coiled cardboard tubes, which served as the foundation for the wax cylinder records.
Besides being far easier to handle, the wax recording medium also allowed for lengthier recordings and created superior playback quality.[3] Additionally the Graphophones initially deployed foot treadles to rotate the recordings, then wind-up clockwork drive mechanisms, and finally migrated to electric motors, instead of the manual crank that was used on Edison's phonograph.[3] The numerous improvements allowed for a sound quality that was significantly better than Edison's machine.
Shortly afterThomas Edison invented thephonograph, the first device for recording sound, in 1877, he thought that the main use for the new device would be for recording speech in business settings. (Given the low audiofrequency of earliest versions of the phonograph, recordingmusic may not have seemed to be a major application.) Some early phonographs were indeed used this way, but this did not become common until the production of reusablewax cylinders in the late 1880s. The differentiation of office dictation devices from other early phonographs, which commonly had attachments for making one's own recordings, was gradual. The machine marketed by theEdison Records company was trademarked as the "Ediphone".
Following the invention of theaudion tube in 1906, electricmicrophones gradually replaced the purely acoustical recording methods of earlier dictaphones by the late 1930s. In 1945, theSoundScriber,Gray Audograph andEdison Voicewriter, which cut grooves into a plastic disc, was introduced, and two years later Dictaphone replaced wax cylinders with theirDictabelt technology, which cut a mechanical groove into a plastic belt instead of into a wax cylinder. This was later replaced bymagnetic tape recording. Whilereel-to-reel tape was used for dictation, the inconvenience of threading tape spools led to development of more convenient formats, notably theCompact Cassette,Mini-Cassette, andMicrocassette.
Digital dictation became possible in the 1990s, as fallingcomputer memory prices made possible pocket-sized digital voice recorders that stored sound on computer memory chips without moving parts. Many early 21st-centurydigital cameras andsmartphones have this capability built in. In the 1990s, improvements invoice recognition technology began to allow computers totranscribe recorded audio dictation intotext form, a task that previously required human secretaries or transcribers.
The files generated with digital recorders vary in size, depending on the manufacturer and the format the user chooses. The most common file formats that digital recorders generate have one of the extensions WAV, WMA and MP3. Many dictation machines record in theDSS and DS2 format. Dictation audio can be recorded in variousaudio file formats. Most digital dictation systems use alossy form ofaudio compression based on modelling of the vocal tract to minimizehard disk space and optimize network utilization as files are transferred between users. (Note thatWAV is not an audio encoding format, but a file format and has little or no bearing on the encoding rate (kbit/s), size or audio quality of the resulting file.)
Digital dictation offers several advantages over traditionalcassette tape based dictation:[4]
Despite the advances in technology, analog media are still widely used in dictation recording due to its flexibility, permanence, and robustness. In some cases, speech is recorded where sound quality is paramount and transcription unnecessary, e.g. forbroadcasting atheatre play; recording techniques closer tohigh-fidelity music recording are more appropriate.
Portable, hand held, digital recorders are the modern replacement for along with handhelds. Digital portables allow transfer of recordings by docking or plugging into a computer. Digital recorders eliminate the need for cassette tapes. Professional digital hand held recorders are available with slide switch, push button, fingerprint locking, and barcode scanning options.
Another common way to record digital dictation is with a computer dictation microphone. There are several different types of computer dictation microphones available, but each one has similar features and operation. Olympus Direct Rec, Philips SpeechMike, and Dictaphone Powermic are all digital computer dictation microphones that also feature push button control for operating dictation or speech recognition software. The dictation microphone operates through aUSB on the computer it is used with.
Call-in dictation systems allow one to record their dictations over the phone. With call in dictation systems, the author dials a phone number, enters a PIN and starts dictating. Touch tone controls allow for start, pause, playback, and sending of dictation audio file. The call-in dictation systems usually feature a Pod that can be plugged into a phone line. The pod can then be plugged into a computer to store dictation audio recording in compatible transcription or management software.
Currently there are several digital dictation applications available for mobile phones. With mobile dictation apps, one can record, edit, and send dictation files over networks. Wireless transfer of dictation files decreases turnaround time. Mobile dictation applications allow users to stay connected to dictation workflows through a network, such as the Internet.
There are two types of digital dictation software:[5]
Recordings can be made over the telephone, on a computer or via ahand held dictation device that is "docked" to a computer.
Digital dictation is different fromspeech recognition where audio is analyzed by a computer using speech algorithms in an attempt totranscribe the document. With digital dictation the process of converting digital audio to text may be done using digitaltranscription software, typically controlled by a foot switch which allows the transcriber to PLAY, STOP, REWIND, and BACKSPACE. Nevertheless, there are Digital Transcription Kits that allow integration with Speech Recognition Software. This gives the typist the option to either type a document manually, or send a document to be converted to text by Software such as Dragon NaturallySpeaking.
