AEA KU4 Studio Ribbon Microphone
AEA KU4 Features
- Unidirectional (supercardioid) pickup pattern
- Reduced proximity effect and room ambience
- Extended top end with classic ribbon smoothness
- Modern, consistent version of the RCA KU3A
AEA KU4 The Supercardioid Ribbon
Having a supercardioid instead of a figure-eight polar response pattern mics sets it apart from other ribbon mics. The AEA 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 miking, while its low-tuned ribbon does not exhibit bass distortion. These characteristics make the KU4 well-suited for the modern studio. It is currently the only supercardioid ribbon microphone in commercial production.
The Legacy of the RCA KU3A
The AEA KU4 is a re-vision of the legendary RCA KU3A, a unidirectional microphone originally designed for the Hollywood movie studios. Also known as the “10001” (for its RCA manufacturing number), it was RCA’s most expensive ribbon microphone and fewer than 600 units were ever manufactured. The KU3A combined the smooth ribbon sound of a 44 with a unidirectional pattern, a wide sweet spot, and reduced proximity bass boost. Expanding an engineer’s range of placement choices, it became a standard at film studios around the world. Today, however, the KU3A is a rare collector’s item, and only a handful of studios or rental houses own them. The few lucky owners of vintage KU3As in great condition like Grammy-winning producer/engineer Kevin Augunas (Sound City Studios) treat their mics as little treasures. Original KU3As are notorious for their sonic inconsistencies due to production tolerances, so with the KU4, we at AEA engineered the microphone from the ground up in order to recreate this seminal design while ensuring flawless consistency from unit to unit. 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.
Ribbon Talk
The AEA KU4 utilizes a medium sized ribbon unlike all other AEA mics. While AEA’s Large Ribbon Geometry TM design offers advantages like extended bass response and maximum SPL level, the KU4’s shorter and narrower ribbon is characterized by a unique upper midrange presence that is particularly interesting for vocals and acoustic stringed instruments. Because of the shorter ribbon, the KU4 is much more similar to the venerable RCA 77 type microphone rather than the RCA 44. By comparison to the 77, the KU4 has a slightly longer ribbon, a fixed polar pattern, and a more natural sounding unidirectional mode. Compared to other non-bidirectional ribbon mics like the Beyer M160, the KU4’s ribbon is 50% longer providing better bass response and higher SPL handling capabilities.
AEA KU4 Applications
- Acoustic Guitar
- Horns
- Upright Bass
- Saxophone
- Piano
- Strings
AEA KU4 Quotes…
Greg Curtis, The Bridge Recording, Glendale, CA – “What I like about the KU4s is that they are a rendition of the originals that leaves nothing to be desired. Every original KU3A that I’ve come across sounds a little different than the other, so it’s nice to have a consistent, wonderful copy of the best originals out there.”
Jason Elgin, Collective Soul, Creed, Lynam, Maylene & The Sons Of Disaster – “I’ve been using the R44, KU4 and R88 on every project. Cello, upright bass, vocals, acoustic guitar and drums. On cello the KU4 made the tone of the wood move completely forward without feeling heavy in the low mids. Tremendous detail. On vocals, acoustic guitar and upright bass I used the R44 exclusively and from top to bottom it gave me that brilliant unmistakeable sound! The top end is like diamonds and the bottom end like honey. Irreplaceable on acoustic instruments. I love the R88 on drums. Whether as an overhead or room, it pretty much was the only mic we needed (aside from a kick mic for a little close sounding bottom end). The long ribbon design makes the mic sound huge. The aesthetics of the mic also make an impression on everyone performing. Beautiful mics.”
Can be factory matched paired as required.
Specifications and Curves
- Operating Principle: Pressure gradient microphone
- Directional Pattern: Supercardioid
- Frequency Range: Below 30 Hz to 20 kHz
- Maximum SPL: 140+ dB SPL (1% third harmonic > 1 kHz)
- Output Sensitivity: 2.8 mV/Pa (-51 dBV) into unloaded circuit
- Output Impedance: 300 Ohms nominal
- Recommended Load Impedance: 1.2 kOhms or greater
- 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:
- Vertical: Level changes with angle, reduced HF response above and below 0° / 180° axis
Transducer element:
- Ribbon Thickness: 1.8 microns ( .0000018 meter ) of pure aluminum
- Ribbon Width: 0.082″ (2.1 mm)
- Ribbon Length: 1.25″ (28.6 mm)
AEA KU4 Accessories:
- Included: Custom storage/shipping case, stand adapter, manual and attached 1.5 meter microphone cable
- Limited Warranty: One year parts and labor, shipping not included. Three year extended warranty if the product is registered.
- Weight with Cable: 4 lb 11 oz (2.15 kg)
- Weight with case: 7 pounds (3.2 kg)
- Height: 12.65″ (32.4 cm)
- Width: 4.62″ (11.7 cm)
- Depth: 3.75″ (9.5 cm)