Home / Neumann 008612 Sound Diffraction Sphere SBK 130 A, 22 mm The SBK 130 A sound diffraction sphere slips onto the KM 130, KM 131 (A/D) and KM 183 (A/D) pressure microphones.
The SBK 130 A (008612) operates on the principle of acoustic diffraction. When placed on a pressure (omnidirectional) microphone, the sphere causes the microphone to behave more like a directional mic at higher frequencies while maintaining its omnidirectional characteristics at lower frequencies. This allows for a unique "treble emphasis" that compensates for high-frequency loss over distance, making it a favorite for orchestral recordings and ambient room miking.
Acoustic High-Frequency Enhancement:
When a microphone is placed at a distance from a sound source—such as an orchestra in a large hall—high-frequency energy is naturally absorbed by the air. The SBK 130 A compensates for this by creating a steady increase in frequency response starting at approximately 2 kHz. The boost reaches up to 2.5 dB at 10 kHz, ensuring that your recordings retain their "air" and crystalline detail even from the back of the room.
Increased Directivity for Better Focus:
While the KM 183 and related models are omnidirectional, the addition of the SBK 130 A makes them more directional at high frequencies. This means the microphone becomes more sensitive to sound arriving from the front and less sensitive to high-frequency reflections from the rear and sides. This "front-to-back" ratio improvement allows for better localization of instruments within a stereo or surround field.
Seamless Mechanical Fit:
The SBK 130 A is designed with a 22 mm internal diameter, allowing it to slip perfectly onto the housing of:
KM 130 / KM 131 (Analog)
KM 183 (Analog)
KM 133 D / KM 183 D (Digital)
KM A / KM D Output stages with the corresponding omni capsules.
The fit is secure and non-destructive, allowing you to quickly add or remove the sphere as the acoustic environment dictates.
Diffuse-Field Optimization:
In a "diffuse field" (where sound arrives from all directions equally, such as a reverberant cathedral), a standard omni mic can sometimes sound "dark." The SBK 130 A transforms the microphone into a diffuse-field equalized transducer, providing a balanced, natural sound that captures the true essence of the architectural space.
High-Frequency Boost: Provides a natural 2.5 dB lift at 10 kHz for distant miking.
40 mm Diameter Sphere: Precision-calculated size for optimal acoustic diffraction.
Directivity Control: Increases high-frequency "focus" while preserving low-end omni traits.
Quick Slip-On Design: Fits 22 mm microphone bodies without tools or modifications.
Wide Compatibility: Supports KM 130, KM 131, KM 183 (A/D), and modular systems.
Professional Finish: Non-reflective black finish to match Neumann KM series hardware.
Orchestral Recording: Ideal for "Decca Tree" setups or main stereo pairs in large halls.
Choral Miking: Captures the brilliance of voices in highly reverberant spaces.
Ambient Room Miking: Adds "air" and detail to room mics in drum or piano sessions.
Acoustic Research: Modifies polar patterns for specialized measurement tasks.
| Feature | Details |
| Model Name | SBK 130 A |
| Product Number | 008612 |
| Outer Diameter | 40 mm |
| Inner Diameter | 22 mm |
| Frequency Lift | Approx. 2.5 dB @ 10 kHz |
| Compatibility | KM 130, 131, 183 (Analog & Digital) |
| Color | Black |
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