Shure 585-SA Unisphere A
The budget Unisphere - a "pop"-suppressing ball-head dynamic that Shure sold for $65 and pitched squarely at the singer who couldn't afford the good one.
Overview
The 585-SA is the high-impedance version of Shure's Unisphere A. It exists for one reason, and Shure's own catalog copy says it: budget. Shure advertised the 585-SA and its low-impedance sibling, the 585-SB, as "budget priced for use in low-budget systems." They were the affordable end of a Unisphere line whose premium member, the Model 565 Unisphere I, listed at $95. The 585-SA carried a list price of $65 in the mid-1960s catalog. Keep that number in mind when you see one on a table at a hamfest. It is not the flagship, and it was never meant to be.
What the 585-SA borrowed from its betters is the Unidyne family's feedback control and uniform pickup pattern, the features Shure described as having made that family "the industry standard for solving difficult public address problems." The 585-SA is a unidirectional dynamic built around that same controlled-pattern idea, with the spherical filter assembly doing the work up front. Shure's literature is specific about what that ball is for. The spherical filter assemblies "effectively control explosive breath sounds ('POP') and wind noise in outdoor locations." Shure recommended the 585-SA particularly for close-talking applications, and noted it lets a performer use space efficiently on small stages or in studios.
The directional behavior is both the sales pitch and the engineering. Shure claimed the Unisphere's pattern gives "practically complete rejection of unwanted audience noises" and helps control the echo that builds in a partially filled hall, the "boom" the company named in its own copy. A club singer or a combo working a room with a hard back wall would care about that. The same catalog page called the shape itself "the greatest for pop singers and combos," which tells you who Shure thought was buying this microphone.
Where the 585-SA sits in the lineup is a matter of impedance, not acoustics. The SA is the high-impedance version. The SB is the low-impedance one, and Shure listed the SB at $58 in the same catalog. High impedance is the friendly option for a short cable run into a consumer-grade amplifier or a small PA head. Low impedance is what you want for long cable runs and for patching into a proper mixing console. The 585-SA, being the high-Z model, is the one aimed at the simplest possible hookup.
The period press treated the Unisphere A as what it was: the cheap seat in a good family. Audio (July 1966, p.33) ran the Unisphere A copy alongside the Unisphere I and the Unidyne III-derived 565, presenting the 585-SA and 585-SB as the budget-priced versions of the same spherical-filter concept. You get a stripped price, not a stripped capsule. The pop-suppressing ball, the directional pattern, and the Unidyne feedback-control heritage are all there. What you give up is the premium model's multi-impedance flexibility and its "maximum handability" small-body design, both of which Shure reserved for the $95 Unisphere I.
The high-impedance output is the limitation to plan around — it wants a short, clean cable and an input that expects a high-Z source. Feed it into a low-impedance console input through a long run and you'll wonder why it sounds thin. Feed it correctly and it's a perfectly serviceable period vocal mic. That's the deal Shure offered in the 1960s, and it hasn't changed.
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