It is usually specified at 315 (MOL 315) or 400 (MOL 400) Hz, and its value marks the point when the third harmonic coefficient reaches 3%. Maximum output level (MOL) is relevant at low and middle frequencies.Performance at low and middle, and at treble frequencies was traditionally characterized by two related but different parameters: Often incorrectly called recording levels, these are always expressed in terms of tapes' output, thus taking its sensitivity out of the equation. Maximum output levels, usually specified in dB relative to the nominal zero level of 250 nWb/m or the 'Dolby level' of 200 nWb/m. From the end user viewpoint, the most important electroacoustic properties of the tape are: Manufacturers of bulk tape provided extremely detailed technical descriptions of their product, with numerous charts and dozens of numeric parameters. Squareness ratio of basic ferric tapes rarely exceeds 0.75 squareness ratio of the best tapes exceeds 0.9. Increase of the ratio defers the onset of compression and distortion, and allows fuller utilization of the tape's dynamic range within the limits of remanence. It is an indicator of tape uniformity and its linearity in analogue recording. Ī useful figure of merit of tape technology is the squareness ratio of the hysteresis curve. High coercivity particles are more difficult to erase, bias and record, but also less prone to high-frequency losses during recording, and to external interference and self-demagnetization during storage. Coercivity of audio tapes varies from 350 Oe to 1200 Oe.
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