Magnetic Reference Laboratory (MRL) is an American company founded in 1972. They produce and sell calibration tapes
/ref> for analog audio magnetic tape reproducers in the open reel
Reel-to-reel audio tape recording, also called open-reel recording, is magnetic tape audio recording in which the recording tape is spooled between reels. To prepare for use, the ''supply reel'' (or ''feed reel'') containing the tape is plac ...
format. It was announced on 11 November 2023 that the company would cease business on 1 December 2023.[Magnetic Reference Laboratory Website](_blank)
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Origins
In 1972 (Jay) John G. McKnight was laid off from Ampex
Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name AMPEX is a portmanteau, created by its founder, which stands for Alexander M. Poniatoff Excellence.AbramsoThe History ...
, as was (Tony) Antonio Bardakos, who was making the calibration tapes for Ampex at the time. Along with Ed Seaman (also an ex-Ampex employee), McKnight and Bardakos decided to start their own calibration tape business, and thus Magnetic Reference Lab (MRL) was born in 1972.[Behind The Gear: Jay McKnight of Magnetic Reference Laboratory", by Alex Kostelnik, from Tape Op, Nr 52 (2006 Mar/Apr)](_blank)
{{webarchive, url=https://web.archive.org/web/20121025131213/http://home.comcast.net/~mrltapes/kostelnik_jay-mcknight-at-mrl.pdf , date=2012-10-25
Products
MRL makes a wide variety of calibration tapes (a tape that "contains test signals used to calibrate a tape reproducer so that it will conform to the accepted standards"gain
Gain or GAIN may refer to:
Science and technology
* Gain (electronics), an electronics and signal processing term
* Antenna gain
* Gain (laser), the amplification involved in laser emission
* Gain (projection screens)
* Information gain in de ...
, azimuth
An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north.
Mathematicall ...
, and frequency response from 32 Hz to 20 kHz)
*Polarity Calibration
*Special signals for Sound Technology or for Audio Precision measurement systems
*Fast Swept-frequency for use with an oscilloscope
An oscilloscope (informally a scope) is a type of electronic test instrument that graphically displays varying electrical voltages as a two-dimensional plot of one or more signals as a function of time. The main purposes are to display repetiti ...
*Slow Swept-frequency for use with a plotter
A plotter is a machine that produces vector graphics drawings. Plotters draw lines on paper using a pen, or in some applications, use a knife to cut a material like vinyl or leather. In the latter case, they are sometimes known as a cutting pl ...
*Single frequencies
*Broadband pink noise
Pink noise or noise is a signal or process with a frequency spectrum such that the power spectral density (power per frequency interval) is inversely proportional to the frequency of the signal. In pink noise, each octave interval (halving ...
*Broadband white noise
In signal processing, white noise is a random signal having equal intensity at different frequencies, giving it a constant power spectral density. The term is used, with this or similar meanings, in many scientific and technical disciplines, ...
*Chromatic Sweep for use on a reproducer's VU meter
A volume unit (VU) meter or standard volume indicator (SVI) is a device displaying a representation of the signal level in audio equipment. The original design was proposed in the 1940 IRE paper, ''A New Standard Volume Indicator and Reference Lev ...
Customers
MRL's calibration tapes are used by anyone who wants to have their analog audio magnetic tape reproducer properly calibrated, including:
* Professional music studios
* Radio stations
* Audio departments at major universities
* Theme parks
References
External links
Magnetic Reference Laboratory
Technology companies established in 1972
Manufacturing companies based in California
1972 establishments in California
Technical specifications