Shure RPM181/O – Omnidirectional Capsule for Beta 181 Microphone

Product Overview

The Shure RPM181/O is the omnidirectional replacement capsule for the Beta 181 small-diaphragm side-address condenser microphone, designed for ambient recording, ensemble miking, and applications where equal sensitivity in all directions is required. It is suited to broadcast studios, performing arts venues, houses of worship, and commercial recording facilities that need to capture room ambience or instrument ensemble sound using the compact Beta 181 body. The capsule installs directly on any Beta 181 body without tools.

Product Description

The omnidirectional polar pattern of the RPM181/O captures sound equally from all directions without proximity effect, making it well-suited to choir and ensemble recordings, orchestral room ambience capture, and acoustic instrument recording in reverberant spaces. For performing arts organizations and broadcast facilities that use the Beta 181 platform with multiple capsule options, the RPM181/O adds ambient and ensemble miking capability to the same microphone body used for close-source work. AV system designers specifying flexible microphone inventories for auditoriums, multi-purpose rooms, and house of worship installations can incorporate the RPM181/O as part of the Beta 181 capsule set without adding separate hardware. The capsule is one of four interchangeable options in the Beta 181 system (bidirectional, cardioid, omnidirectional, and supercardioid).

Key Features

• Omnidirectional Polar Pattern — Equal sensitivity in all directions with no proximity effect, suited to choir, ensemble, and ambient recording applications.
• Beta 181 Capsule System Compatibility — Mounts to any Beta 181 body without tools, extending the polar pattern range of an existing microphone investment.
• No Proximity Effect — Omnidirectional operation eliminates the low-frequency proximity effect present in directional capsules, providing natural tonal balance at varying source distances.
• Ambient and Ensemble Miking — Suited to choir, orchestra, and room ambience capture in auditoriums, houses of worship, and broadcast studio environments.
• Compact Side-Address Form Factor — The Beta 181 body allows discrete placement in choir lofts, above ensemble sections, and in architecturally constrained positions.
• Part of the Four-Capsule Beta 181 System — Used alongside RPM181/BI, RPM181/C, and RPM181/S capsules for a complete polar pattern toolkit from a single microphone body platform.

Typical Applications

• Choir and ensemble overhead miking in house of worship
• Orchestral room ambience and section miking in auditoriums
• Broadcast studio ambient microphone placement
• Multi-purpose room and all-hands room instrument and room capture
• Performing arts venue ensemble recording

Technical Specifications

Frequently Asked Questions

What is the primary application for the omnidirectional capsule?

According to Shure, the RPM181/O is ideal for ambient recordings and instrument ensemble applications, including choir overhead, orchestral section miking, and room ambience capture.

Does the omnidirectional capsule have proximity effect?

No. Omnidirectional microphones do not exhibit proximity effect, so low-frequency response remains consistent regardless of source distance.

Is the RPM181/O compatible with the same Beta 181 body as other capsules?

Yes. All RPM181-series capsules are interchangeable on a single Beta 181 body, allowing facilities to deploy one body with multiple polar pattern options.

Does the capsule require phantom power?

Yes. The RPM181/O requires 48V phantom power from the connected preamp or console.