KU Series: KU4 vs KU5A

The KU Series: KU4 vs KU5A

The KU Series of ribbon microphones, AEA’s collection of supercardioid ribbons, are some of the most flexible microphones in the entire line. These microphones break new ground in ribbon technology with their focused directionality that rejects room reflections, loud ambience, and bleed from other instruments in the studio or on the stage. The KU Series comprises the KU4 and KU5A and aside from their shared polar pattern, each microphone is itself unique in nearly every sense.

What’s Similar?

Both the KU4 and KU5A feature a supercardioid polar pattern which sets them apart from traditional figure-of-8 ribbons by providing superior rejection from the sides and the rear of the mic. This feature makes it easier to position these mics amidst multiple other sources in a live recording scenario, or on a live stage. The supercardioid polar pattern of KU Series microphones is achieved with an acoustical labyrinth that delays the sound that reaches the rear side of the ribbon.

Both mics feature a captive cable that is tethered to an integrated yoke mount. The yoke of the KU4 and KU5A allow for enhanced maneuverability when positioning the mics in tight spaces.

What’s Different?


The KU4 stands apart as the brightest of any other ribbon in the AEA lineup. Although it still delivers the balanced low-end one expects of AEA ribbons, the extended top-end response of the KU4 is unparalleled. It draws significant inspiration in form and function from the RCA KU-3A, a cardioid, side-address ribbon mic developed in 1948 for Hollywood’s motion picture industry. An interesting characteristic of the KU-3A was its use of cow hair as dampening material in the labyrinth, which led to some inconsistency in sound between each mic. The KU4 design solved that issue by implementing fiberglass in the labyrinth that grants consistency across all units.


The KU5A is AEA’s first end-address supercardioid ribbon and features the most focused directionality of any AEA ribbon mic before it. Although inspired by the form factor of the RCA BK5, the KU5A delivers vastly different sound with superior rejection from the sides and rear of the mic. Equipped with active electronics that grant flexibility with any preamp and an integrated high-pass filter switch for close-range recording, the KU5A is a true progression of modern ribbon technology. It’s low-profile and end-address directionality make it simple to position and work with.


KU:Two Supercardioid Siblings

Different in form, yet similar in function, the two KU Series microphones offer a new approach to ribbon recording. Where traditional figure-of-8 ribbons combine room sound and direct source sound, the unique KU4 and KU5A deliver focused acceptance, superior rejection, and near-field possibilities when recording virtually any source.

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