NT cassette
The NT cassette is the world's smallest magnetic tape cassette for digital audio recording. The system was developed by Sony in the early 1990s .
The corresponding devices, also known under the name Scoopman , of which only two different models have been manufactured over the years, were based on the shape and size of the analog dictation devices that were widely used at the time (this applies particularly to the first of the two models, the NT- 1, zu) and were therefore often incorrectly referred to as such. In fact, the NT recorders offered a sound quality that can be described as suitable for studios and is only slightly below the quality of a CD . NT cassettes were available with a playing time of 60, 90 and 120 minutes. The belt speed is 6.35 mm / s, the belt is 2.5 mm wide.
technology
From a technical point of view, NT is a miniaturization of the DAT system developed a few years earlier . The main difference to DAT lies - in addition to the size of the devices and media - in the much thinner and narrower tape, a lower tape speed, the two-sided playability of the cassettes and a slightly modified recording and playback process. Also, the tape does not have to be pulled out of the cassette.
NT works on the eponymous N on- T racking Helical scanning . In contrast to DAT, in which the tape speed and the track position are precisely adjusted to the individual tracks during playback, which requires very precise and complex mechanics, this adjustment is only very rough with non-tracking. The head drum does not rotate synchronously with the tape drive, but at excessive speed, which means that sections of several tracks are scanned with each scanning process. These overlapping sections are then sorted in the digital processing block and put back together in the correct order.
The recording is uncompressed in PCM with a sampling rate of 32 kHz and a word length of 12 bits with non-linear quantization , which corresponds to the recording format of DAT in long play mode.
Weaknesses of the system
Because of the very narrow and thin tape at extremely low tape speed and the resulting high recording density, NT was very prone to failure. There were very frequent dropouts, especially at the beginning and end of the tape, and the cartridges only had a short life. In addition, the devices did not have any digital outputs, so that the recordings could be transferred to other systems, such as B. DAT, was only possible over a lossy analog connection.
Development and market situation
At the time of their market launch and for a few years afterwards, the NT recorders were by far the smallest digital audio recorders in the world. The first device, the Sony NT-1, hit the market in 1992. The second and last model followed in 1996, the NT-2, which has seen a number of improvements compared to its predecessor. The control was no longer via mechanical buttons, but via an electronic tap-button logic control, the device had a much larger LC display with more extensive displays, had an uninterrupted auto-reverse function, which made turning the cassette superfluous, and was with a wired remote control. The design has also been made more appealing and much more modern.
Due to the susceptibility to faults, the lack of compatibility with other systems and not least because of the extremely high device prices, which even exceeded the price of a portable DAT recorder, NT was hardly able to establish itself on the market. With the increasing miniaturization of the portable minidisc recorder and the appearance of the first memory card-based audio recorder at the end of the 1990s, NT finally disappeared from the market.
Today the system is practically irrelevant, devices and cassettes are only available used and are only of interest to collectors of technical curiosities.