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Earthworks Audio QTC50

Omnidirectional Condenser Microphone

The QTC50 is Earthworks’ flagship omnidirectional condenser microphone. It is nearly identical to the QTC40, but is rated for better impulse response and extended high-frequency response. Earthworks presents it for recording quiet acoustic sources.

Note, however, the mic’s self-noise: at 22dBA, the mic’s noise might be audible against a quiet source.

The small electret condenser capsule produces no proximity effect, allowing placement very close to a source without creating low-frequency buildup.

The QTC50 meets Earthworks’ requirements for a “High Definition Microphone:”

• Fast transient response (aka “impulse response”) … “The impulse response is the single best measure of the overall sonic accuracy and fidelity of a microphone. “


• Fast diaphragm settling time … “If the diaphragm is still vibrating from the sounds it picked up previously it will tend to mask or color many or all of the subtle sounds that follow.”


• Extended frequency response … “studies have shown that acoustic sounds and overtones of musical instruments extend to beyond 100kHz.”


• Minimal signal path … Pattern controls, pads, and filters can degrade the sonic qualities of the mic.


• High SPL handling … Low distortion up to and beyond 140dB.


• Low impedance … The mic must able to put its signal through a long cable run without signal loss.


• Consistent polar pattern … maintain a consistent pickup pattern over the mic’s full frequency range, to reduce phase cancellation at the edges and “spotlighting” of higher frequencies.

The QTC model name prefix means “Quiet / Time Coherent.” The QTC mics are called “quiet” in comparison to the TC series (which are rated at 27dBA of self-noise).

“Time Coherent” is Earthworks’ means of distinguishing the tiny omni capsule design from all the directional and larger-diaphragm condensers on the market. According to David Blackmer, other designs “smear the signal in the time domain” due to inadequacies of their design:

• larger diaphragms resonate like drumheads when excited, coloring the recorded sound.
• most mic capsules are mounted inside of a “cage” that causes resonances and reflections, introducing phase cancellation to the signal.
• Directional mics “[sample] the sound at multiple points,” reducing the mic’s accuracy.

In contrast, the (~6mm) omni capsule used in QTC mics avoids all these problems, producing a very accurate, realistic, and uncolored sound.

Earthworks

Our claim of Time Coherent Response means these models do not smear the time domain as most microphones do. Earthworks microphones have exceptional impulse response and diaphragm settling time.

Also available as a Matched Pair, (model number QTC50mp).

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Specifications

Frequency Response - OmnidirectionalClick Graph to Compare!

Pickup Patterns	Pads & Filters
Omnidirectional (30 mV/Pa; 3 - 50,000 Hz)

Capsule Dimensions	Impedance	SPL/Noise
Capsule diameter: 6mm	100 Ohms (Low)	Max SPL: 142 dB Self-noise: 22.0 dB(A)

Weight	Length	Max Diameter	Interface(s)
225g (7.94oz)	229mm (9.02'')	22mm (0.87'')	3-pin XLR male (1)

Power Specifications
Requires phantom power Phantom voltage: 48v

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