Shure SM81-LC
A small-diaphragm condenser that earned its keep on acoustic instruments and cymbals, at a price that made studios think twice.
Overview
The SM81-LC weighs just 8 oz. It is a unidirectional condenser, and Shure aimed it squarely at the acoustic-instrument and cymbal market. Distributor literature of the period put the pitch bluntly: for a few hundred dollars you could enjoy a fine condenser microphone. That "few hundred" was stretching it. One distributor catalog carried a manufacturer's list price of $562.00, with the usual "call for your best price" language attached. A period buyer's guide put the street figure closer to $410.
Shure specified low distortion of 0.5% and a maximum SPL of 135 dB before clipping. That puts it comfortably in front of a snare or a close-miked acoustic guitar. For louder sources, a 10 dB attenuator raises the ceiling to 145 dB SPL, which is serious headroom for a mic this size. Sound and Communication (September 1988, p.39) listed the SM81-LC with a 146 dB maximum SPL figure in its survey table, a bit higher than Shure's own literature.
The frequency response runs 20 Hz to 20 kHz. A selectable low-frequency curve compensates for proximity effect, low-end rumble and handling noise, so the user can tame the bottom end at the source rather than in the mix. The polar pattern is cardioid and the operating principle is condenser, per a contemporary equipment survey that placed the SM81-LC among Shure's working-microphone lineup alongside the SM58LC, SM85LC, SM87LC and SM94LC.
What the SM81-LC was built for is spelled out plainly in the period documentation: acoustic instruments, choir, and cymbals. That's a specific brief, and it's a fair summary of where this mic turns up in studio inventories. And a home-studio equipment list from the same era shows three SM81LCs in a working songwriter's mic locker next to a pair of KSM44s, a VP88, and the usual Shure dynamics. Three of them. That's not a mic you buy one of; it's a mic you buy a matched set of, because it's the kind of tool that gets used in pairs on a stereo source.
The $562 list and $410 street figures come from undated manufacturer documents. A September 1988 Sound and Communication survey (p.39) lists the SM81-LC at $367.00. That makes it a mid-priced condenser, more than an SM58 by a wide margin and less than the flagship studio condensers of the day. Shure's own catalog placed it above the SM94LC and SM96LC in price and below the SM89.
Collectors and working engineers tend to treat the SM81-LC as a known quantity rather than a cult object. The documentation treats it the same way, with specs and applications and no breathless prose. The 8 oz weight, the attenuator, the low-frequency curve switch and the cardioid pattern are what the sources list. The period sources don't treat it as a rarity. They treat it as inventory.
The surviving documentation doesn't say when production began or ended, how many were made, or what the current used market looks like. The SM81-LC appears in catalogs and studio lists across the late 1980s and into the 2000s, which suggests a long run, but the exact dates aren't established in the available sources. Buyers chasing one today should expect the usual caveats for a condenser of this age. The capsule and electronics are what matter, and period documentation won't say how a given example has been treated over the decades.
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