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BidirectionalRoyer Labs SF-2

Bidirectional Active Ribbon Microphone

The SF2 is an active ribbon microphone with a figure-8 polar pattern. It is essentially one-half of an SF-24.

Like the R-122 and SF-24, the SF2 uses David Royer’s innovative active circuit design: a step-up transformer to increase the gain of the signal coming off the ribbon, followed by an active impedance conversion circuit that adds no gain at all, but creates a balanced output signal at an appropriate impedance level.

The transformer is a Royer custom toroidal model.

You can hear this mic on alto sax and character voice in the $60,000 Ribbon Mic Shootout.

Royer Labs
The SF-2 Story: Twenty prototype SF-2’s circulated in major studios and scoring stages for years before the microphone’s release. They were extremely well received in classical circles, where they excel on choir, piano, woodwinds, strings and many other applications. They were also well received in studios focusing more on acoustic instruments, singer/songwriters, etc. We couldn’t get most of the prototypes back…

The SF-2 retails for $2495, including an elastic shockmount. Royer Labs also sells a deluxe edition, which includes a wooden storage case, the Royer Sling-Shock shockmount, and a Royer custom mic cable, for $3295.

The Royer Labs SF-2 is also known as: SF-1A.

The mic was released in 2012.


Pickup Patterns Pads & Filters
Bidirectional (12.6 mV/Pa; 30 - 15,000 Hz)
Ribbon Construction Impedance SPL/Noise
Gauge: 1.8 microns 200 Ohms (Low) Max SPL: 130 dB
Weight Length Max Diameter Interface(s)
470g (16.58oz) 202mm (7.95'') 38mm (1.50'')
  • 3-pin XLR male (1)
Power Specifications
  • Requires phantom power
  • Phantom voltage: 48v

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