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C 451 B Microphone Sets

CardioidAKG Acoustics C 451 B

Cardioid Pencil Condenser Microphone

The original AKG C 451-C, created in 1969, was the company’s first FET condenser, and was a very successful product due in part to the great sound of the cardioid CK-1 capsule and the modular design of the microphone (which included pads, gooseneck and swivel extensions, plus 10 other capsules covering every polar pattern).

The “CMS” (Condenser Modular System) series was discontinued in the 1990s, after which AKG redesigned and reintroduced what is now called the “C 451 B.”

Features at a glance:

  • Identical acoustics to the CK1 capsule
  • Precise, nearly frequency-independent cardioid pickup pattern
  • Extremely accurate signal transfer and ruler-flat on-axis frequency response

The new capsule employs a 3-micron gold-sputtered diaphragm designed to be insensitive to handling noise. It is an electret design, according to MIX Magazine.

The electronics and body were redesigned to be more rugged and reliable, to the extent that the modular-capsule system (which provided versatility at the expense of complexity and increased risk of damage to capsules, threads, and etc) was replaced by a fixed-cardioid capsule.

The formerly modular pads have been incorporated into the onboard electronics; a switch on the mic body provides a 10 or 20db pad (giving the mic an extremely high max SPL rating of 155 dB, which essentially means you can mic the loudest thing in the studio without fear of distortion).

A second switch on the body provides a high pass filter (aka bass roll-off), attenuating 12 dB per octave below 75 or 150 Hz (selectable).

Note that this basic design, including the 3-position pad and 3-position HPF, have been cloned in numerous competitive mics, such as the Feilo CR1-14, ADK SC-2.

The SA 40 stand adapter and W 90 windscreen are included as standard accessories.

These mics are available in computer-matched stereo pairs, known as the C451B/ST. Such pairs are within 1 dB to each other in sensitivity and also within 1 dB to each other in the range of 200 Hz to 15,000 Hz of the individual frequency response when used in cardioid mode. Pairs are selected from a large quantity of individual microphones using the described criteria.

Using this matched pair for stereo recordings utilizing various techniques will provide for a good and stable balance without frequency-dependent shifting of the stereo panorama.

Resolution, 2002

The original [C451 + CK-1 Cardioid capsule] was notable for its treble lift, and this reissue is certainly similar in that respect… with a reduced treble response off-axis you are able to control the sound considerably by placement…

The AKG Acoustics C 451 B is also known as: 451B, C451B.

The mic was released in 2001.


Frequency Response - CardioidClick Graph to Compare!
C 451 B Cardioid Frequency Response Chart
Pickup Patterns Pads & Filters
Cardioid (9 mV/Pa; 20 - 20,000 Hz)
  • Pad: -10 dB (Via Switch)
  • Pad: -20 dB (Via Switch)
  • Filter: -12 dB/octave @ 75Hz (Via Switch)
  • Filter: -12 dB/octave @ 150Hz (Via Switch)
Capsule Dimensions Impedance SPL/Noise
Diameter n/a
Diaphragm gauge: 3 microns
200 Ohms (Low) Max SPL: 155 dB
Self-noise: 18.0 dB(A)
Weight Length Max Diameter Interface(s)
125g (4.41oz) 160mm (6.30'') 19mm (0.75'')
  • 3-pin XLR male (1)
Power Specifications
  • Requires phantom power
  • Phantom voltage: 9 - 52v

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