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Pearl Microphone Laboratory - PML

I have always been impressed by the genious of the Swedish engineer Rune Rosander, and his achievement in the field of microphone technology. Since 1941, Pearl Microphone Laboratorium has been one of the most exciting developers and manufacturers of microphones, even worlwide.

Mr Rune Rosander posing with his new series of microphones at a Pro Audio convention in 1987.

 

 

    Rune Rosander (left) receiving the AES Fellowship Award 1989.

Pearl from inception became a vertically integrated company producing every component part of their products; even to growing their own crystals, hence the name - "Pearl". Already in the mid 30´s Rune Rosander, as a young engineer, turned into developing microphones. In the early days mainly crystal microphones and the company was housed in Runes home located in a Stockholm suburb. In the late 50´s the company moved to larger facilities in Stockholm and finally the whole operation moved in 1960 to Åstorp in southern Sweden where a larger office and production facillities was built and completed in 1961.

The new building at Knutsgatan in Åstorp summer 1961 providing space for laboratories, service and manufacturing.

Knutsgatan 2005.

Unfortunately the whole building burned down to the ground completely in June 2006.At the time the building contained a hardware store.

After serving companies like Luxor ,Tandberg and the Swedish Radio Broadcasting company with microphones, Rune Rosander was the first to develop a semiconductor amplified microphone: the "Relucsistor Amplifier", with germanium semiconductors imported from the US, it was introduced in 1953. The RTD-6 and RTT-8 was examples of these Relucsistor microphones.

The Åstorp plant early 1960:s assembly of dynamical capsules (Left) and one of the Bruel and Kjaer instruments from the laboratory (Right) still alive today! 

                                                Standard rectangular capsule                                           Pearls New "ELM" 7:1 linear capsule.  

The rectangular, introduced in the mid 50´s, provided exceptionally straight and resonance free frequency curve. The rectangular concept is still alive and you can find it in several of Pearl microphone models of today as well as the new exciting "ELM" solution.

A range of condenser microphones where developed during the 1950´s. One of the first was the remotely controled 8-CK. A natural spinn-off was the CK and C8 models. The CK had localy changeable pattern between cardioid and omnidirectional and the C8 had cardiod and figure eight patterns. Other common Pearl microphes from the 50´s and 60´s were the C-2, C-12, C-14 and K-12.

 In 1957 Rune patented a stereo microphone, witch later lead to a model of 8CK with two amplifiers and two capsules one omnidirectional and one bi-directional producing a MS-stereo signal.
Other early stereo models were the ST-5 and ST-6.

Apart from the more studio shaped microphones Pearl Mikrofonlaboratorium also produced a range of different dynamic modells as well as specially designed condenser models, of witch for example the C4 and C2 models were extremely slim. In the late 60´s the switch to semiconductor and later FET impedance converters and amplifiers resulted in a number of models. The first semiconductor model was the TC-4 developed already in 1965, followed by the TC-4V in 1967. The stereo microphone from the 70´s: the ST-8 consisting primarily of two TC-4 mounted together. Another famous was the DC-63 with up to 44 different patterns between all the characteristics.

Rune Rosander also introduces the "symsi" 48/24 Volt powering system producing symetry in the signal och feeding cables.

My rewiev of Pearl stops here only to mention the TL-4 presented in 1984 and in the years to come "Pearl" where reorganized now under the leadership of Bernt and Margita Malmqvist.

The TL-4 introduced in 1986 a milestone and the first of a series of exciting transformer less models with a completely new and innovative amplifier design.  

Bernt Malmquist had been a developer and executor at Pearl Microphone Lab since 1954 and is the father of many solutions and products over the years, since 1987 Bernt and his family are the owners of the company.

The introduction of the completely new capsule concept "ELM"  (se picture abowe!) in 2004 is indeed very promissing. The ELM utilizes a rectangular capsule with an extreme (7:1) length/width ratio. The new linear capsule has more than twice the surface area of large-diameter round capsules giving it excellent signal/noise ratio while avoiding in-band resonance. In addition, at high frequencies the narrow width provides uniformity of directional pattern in the lateral sense, while canceling reflections from the floor and ceiling.

As I always been interested in and dedicating my focus on tube electronics another great happening is the introduction of the CT 40 and DT 40! Both tube microphones with the rectangular dual capsule and quality Nuvistor tube amplifier. The CT40 has a fixed Cardioid pattern while the DT40 can be configured for five different patterns.    

It really warms my heart that Pearl Microphone Laboratory today, not only exists, but still also is in the front line of development regarding capsuledesign. 

Take a look at Pearl´s new and exciting microphones at Pearl Mikrofonlaboratorium

  Crystal capsule type "152" probably from the late 30´s or early 40´s. (thanks to Bosse Hansén Gothenburg!)

 

BM-3   Table Chrystal Microphone standard accesory with Swedish Manufacturer Luxor Radios Wirerecorder from 1949. Later raplaced by the LD-7 up until 1954 when Luxor completely focused on reel to reel taperecorders.   
    Ribbon Microphones late 1940´s.                                                                                     BD-5 and BD-7 two of all the ribbin microphone models developed by Rune Rosander during the 40´s.                KBD a dynamic and a ribbon microphone combined! A perhaps not so common concept  but it could be found in the Pearl microphone program during the early 50´s.