Linn Isobarik

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.

"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.

[1] 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.

[4][5] Hi-Fi for Pleasure noted that the speakers' impedance, although quoted at 3 ohms nominal, dipped considerably at some parts of the audio spectrum.

[1][4] Such demands happened to make Naim amplification the perfect match because of its high current delivery capabilities and its toleration of near short circuits.

[Note 1] As a three-way loudspeaker system employing six individual drive units, each Isobarik kabinet has two tweeters, two midrange drivers and two woofers.

[7] One driver of each frequency range faces forward; a second tweeter and midrange are mounted on the top surface of the enclosure, and one bass unit is hidden from view.

[8] Manufacturer's leaflets advise positioning of the speaker close to a rear wall and approximately 2 to 3 feet (60 to 90 cm) from corners.

According to Art Dudley of Stereophile, Linn also maintained provocatively that "anyone who would design, manufacture, buy, sell, or positively review a loudspeaker made to be installed away from room boundaries was a fool".

[1] Three NAP 250 amplifiers, fed by a 3-way Naim electronic crossover, would typically be used, one for each pair of the doubled-up treble, midrange and bass units.

[7] The extremely rigid 55-litre cabinet is constructed using 19mm high-density particle board that is strategically damped in places, and extensively braced.

Drivers' metal baskets are treated to reduce the effects of vibration, and the enclosure designed and constructed to control energy.

[4] Each unit of the Isobarik cabinet weighs 40 kilograms (88 lb), and is designed to be placed on stands that are 33 centimetres (13 in) tall so that the tweeter is positioned at the listener's ear-level.