recordinghacks

Earthworks Audio SR30HC

Hypercardioid Condenser Microphone

Introduced in 2000–2001 as the SR78, the SR30HC is a hypercardioid version of the cardioid SR30 (originally SR77). The mic is a transformerless electret condenser built to Earthworks’ characteristic performance specifications for uncolored sound, fast impulse response, and extended frequency response.

Earthworks’ description of the SR30HC’s Hypercardioid pattern control as “near-perfect” refers to the mic’s unusual ability to provide a nearly flat, uncolored response across the front hemisphere (±90°), with very little frequency-specific attenuation even at the edges of the range.

Like the other SR-series directional mics, the physical design of the SR30HC is covered by patent #6,091,829 (July, 2000). The patent describes a structural component — a tapered cone behind the capsule — that allows the mic to maintain an even Hypercardioid polar response.

Patent 6,091,829

The tapered structure has a generally conic shape to provide a gradually increasing acoustic impedance… [it] preferentially collects signal components from behind the microphone and ducts them into the rear ports of the [capsule]; and guides reflected, unwanted signals outwardly and away…

[It] improves the front frequency response of the microphone, and [provides] more-effective rear-port signal cancellation, thereby providing a better front-to-back signal ratio than provided in the prior art.

How does the SR30 differ from the SR30HC?

The frequency response of the two mics is nearly identical across the front hemisphere of sensitivity (-90°–+90°). The differences are limited to sensitivity behind the microphone.

Whereas the SR30 has deep nulls at 180° in the 1–2kHz region, the SR30HC has a rear lobe of sensitivity there, with nulls at ±145°. In general, the SR30HC is much less sensitivity to sounds from behind the microphone — as is typical for a Hypercardioid polar pattern.

The Earthworks Audio SR30HC is also known as: SR78.

The mic was released in 2000.

Specifications

Frequency Response - HypercardioidClick Graph to Compare!

Pickup Patterns	Pads & Filters
Hypercardioid (22 mV/Pa; 30 - 30,000 Hz)

Capsule Dimensions	Impedance	SPL/Noise
Capsule diameter: 9mm	100 Ohms (Low)	Max SPL: 145 dB Self-noise: 22.0 dB(A)

Weight	Length	Max Diameter	Interface(s)
225g (7.94oz)	212mm (8.35'')	22mm (0.87'')	3-pin XLR male (1)

Power Specifications
Requires phantom power Phantom voltage: 48v

Did we get anything wrong on this page? Please let us know!