Linn Isobarik

The Linn Isobarik, nicknamed "Bariks" or "Briks", is a loudspeaker designed and manufactured by Linn Products. The Isobarik is known for both its reproduction of low bass frequencies and being very demanding on amplifiers.

Launched in 1973, the Isobarik DMS, Linn's maiden and flagship loudspeaker was based on and named for the isobaric loading principle invented in the 1950s. The speaker exists also as the Isobarik PMS – destined for the professional market. Although discontinued in 1992, it remains popular among audiophiles.

While other loudspeaker manufacturers sought to outperform each other to produce more quantum bass output from their products, Linn was seeking clear undistorted low frequency bass. Linn theorised a design whose bass could go all the way to DC and be without fundamental resonance. The quest for that extra octave of "dry and extended bass sound" and more accurate reproduction resulted in the Isobarik.

Linn launched the original Isobarik DMS loudspeaker in 1973, the year following the release of its first product, the Sondek LP12. "DMS" is the contraction for "domestic monitor system", and is designed to be driven passively in the home setting – it incorporated a crossover within the loudspeaker cabinet. The Isobarik PMS ("professional monitor system") loudspeaker launched in 1977, destined for the professional market is without the internal crossover. This latter configuration opens up more wiring and driving options, in particular active operation and tri-amping.

The Isobarik is so named as it employs the isobaric loading principle invented by Harry Olson in the 1950s: two bass units are mounted in a sealed container and driven in parallel so as to effectively double the speaker enclosure volume and extend its bass frequency response beyond what would be possible for otherwise identical speakers. Linn used a variant of the isobaric principle and patented the use of two bass drive units ("woofers") facing forward in an isobaric arrangement in early 1974.

In 1988, Linn externalised the crossover of the DMS to boards with nominal 4-ohm impedance designed to lie flat at the base of the stands. Upon that change, the original distinction between DMS and PMS disappeared along with the suffix designation. The "DMS" was thus discontinued, although "Isobarik PMS" remained on price lists until the speaker was discontinued in 1992.

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Wikipedia