Go directional, a rare opportunity with ribbons, and bring that size and full smoothness to your music!
The KU4 is unmistakeably a ribbon microphone, with a characteristically smooth ribbon sound. Like other ribbons, its lightly-tensioned, ultra low mass ribbon has a frequency response beyond 20 kHz, an accurate transient response, and no upper midrange resonances common to large condenser mics.
However, having a supercardioid instead of a figure-eight polar response pattern mics sets it apart from other ribbon mics. The KU4's suppressed rear lobe reduces the pickup of room ambience and is especially useful when the rear of a figure-eight pattern would pick up undesirable sounds. The KU4's reduced bass proximity effect facilitates closer micing while its low-tuned ribbon will not exhibit bass distortion. These characteristics make the KU4 well-suited for modern studio production.
The Legacy of the RCA KU3A
The KU4 is a re-envisioning of the legendary RCA KU3A, a unidirectional microphone originally designed for the Hollywood movie studios. It combined the smooth ribbon sound of a 44 with a unidirectional pattern, wide sweet spot and reduced bass proximity effect. It became a standard at film studios around the world because it expanded an engineer's range of placement choices. Today, however, the KU3A is a collector's item, and few studios or rental houses own them. AEA is proud to put this microphone back into the hands of modern users.
The KU4 is your ticket to discovering why RCA unidirectional ribbon microphones have been used in professional studios for over 60 years. AEA is honored to play a part in its history, and invites you to listen to the KU4 and claim your part of this legacy.
- Supercardioid pattern for excellent rear rejection
- Reduced proximity effect
- Smooth, high-bandwidth frequency response
- Authentic New Old Stock RCA ribbon material
- High-quality anodized & nickel-plated finish
- Custom AEA transformer, neodymium magnets
- Consistent Quality
- Field-tech replaceable ribbon assembly
- Hand-crafted in Pasadena, California
- Frequency Response: Below 30 Hz to above 20 kHz
- Maximum SPL: 140 + dB SPL above 200Hz for 1% third harmonic
- Output Sensitivity: 2.8 mV/Pa into unloaded circuit
- Output Impedance: 300 Ω nominal
- Recommended Load: 1.2 KΩ or greater
- Phantom power: Not required or recommended
- Polarity: Pin 2 high for positive pressure at the front of the microphone.
- Connector: XLR-3M wired to a 1.5 meter captive cable
Off Axis Response
- Polar Pattern: Supercardioid
- Relative Output at 180° (dB): -12
- Angle of Maximum Rejection: 135°
- Ribbon Thickness: 1.8 microns ( .0000018 meter ) of pure aluminum
- Ribbon Width: 0.082” (2.1 mm)
- Ribbon Length: 1.25” (28.6 mm)