Sennheiser SK 9000 A1-A4 Bodypack transmitter, digital, HD and LR mode, 3-pin SE socket, 470-558 MHz

Product Overview

The Sennheiser SK 9000 A1-A4 is a professional digital bodypack transmitter for the Digital 9000 wireless system, covering the A1-A4 frequency range (470–558 MHz). Designed for demanding live production, broadcast, and theater applications, it accepts lavalier microphones, headset mics, and line-level instrument signals through its 3-pin SE (Lemo-style) connector. The transmitter supports both HD (High Definition) uncompressed and LR (Long Range) transmission modes, giving audio engineers the flexibility to prioritize audio quality or operating range depending on venue requirements. The die-cast magnesium housing is lightweight and sufficiently compact to conceal in a costume or clip discreetly to a performer's body.

Product Description

The SK 9000 A1-A4 bodypack transmitter is engineered for professional environments where audio quality and RF reliability are non-negotiable. The A1-A4 frequency range spans 470–558 MHz with an 88 MHz switching bandwidth, providing extensive channel coordination headroom even in congested spectrum environments. In HD mode, the transmitter sends uncompressed 24-bit digital audio at 10 mW RF output, delivering a direct, artifact-free signal chain that stands up to the most critical listening environments. In LR mode, the proprietary SeDAC codec operates at 25 mW, significantly extending the operational range for large venues or outdoor productions where performers may be far from the receiver rack.

The 3-pin SE connector is Sennheiser's professional locking input standard, compatible with a wide range of lavalier and headset microphones. The icon-based menu interface is straightforward to navigate, and infrared synchronization with the EM 9046 receiver transfers frequency, gain, and low-cut filter settings in a single step. The automatic lock mode secures all transmitter parameters against accidental or unauthorized changes during a live performance. Power is delivered by Sennheiser's BA 61 rechargeable lithium-ion battery or the B 61 battery case with AA cells, both available separately. The Digital 9000's equidistant, intermodulation-free frequency grid allows up to dozens of SK 9000 units to operate simultaneously without mutual interference, which is critical for large corporate productions, theater runs, and broadcast environments. Optional AES 256 encryption is available for applications requiring secure audio transmission.

Key Features

• A1-A4 Frequency Range (470–558 MHz) — 88 MHz switching bandwidth with equidistant, intermodulation-free channel grid for dense RF environments.
• HD Mode — Uncompressed 24-Bit Digital Audio — 10 mW RF output; cable-like audio transmission with no codec artifacts for critical listening applications.
• LR Mode — Extended Range Transmission — SeDAC proprietary codec at 25 mW for maximum throw in large venues and outdoor applications.
• 3-Pin SE Connector (Lemo-Style) — Professional locking input for lavalier microphones, headset mics, and line/instrument signals.
• Die-Cast Magnesium Housing — Lightweight and concealable; withstands the physical rigors of touring and theatrical productions.
• Infrared Sync with EM 9046 — One-step transfer of frequency, gain, and filter settings from receiver to transmitter.
• Automatic Lock Mode — Prevents parameter changes during live performances without authorization.
• Icon-Based Menu Interface — Intuitive navigation for fast setup in time-pressured environments.
• Optional AES 256 Encryption — Protects audio signal against unauthorized interception for broadcast and corporate applications.
• Rechargeable Battery System — BA 61 lithium-ion pack or B 61 AA battery case; both sold separately.
• Compatible with EM 9046 Receiver — Full Digital 9000 feature set; also operates with EM 6000 and EK 6042 in LR mode.
• Intermodulation-Free Channel Operation — Equidistant frequency grid supports high channel counts in shared RF environments.

Typical Applications

• Theater productions requiring concealed transmitters for costume integration
• Broadcast television with presenters or talent wearing lavalier microphones
• Large-scale corporate presentations and multi-speaker conference productions
• Houses of worship with multiple wireless microphone channels
• Touring musical productions and theatrical runs
• Film and video production with talent wearing body-worn transmitters
• Secure presentations requiring encrypted audio transmission

Technical Specifications

Frequently Asked Questions

Q: What type of microphone connector does the SK 9000 use?

The SK 9000 uses a 3-pin SE connector, which is a Sennheiser locking Lemo-style socket. It is compatible with Sennheiser-standard lavalier microphones, headset microphones, and instrument/line sources using the matching connector type.

Q: What is the difference between the SK 9000 A1-A4 and the A5-A8 variant?

The A1-A4 variant operates from 470 to 558 MHz, while the A5-A8 variant covers 550 to 638 MHz. Both share the same hardware and features; the difference is purely the licensed frequency range. Choose the variant that aligns with your local RF environment and any existing Digital 9000 gear.

Q: Does the SK 9000 support HD (uncompressed) audio?

Yes. In HD mode, the SK 9000 transmits uncompressed 24-bit digital audio at 10 mW RF output, providing a signal chain comparable to a wired connection for critical audio applications.

Q: Which receiver is required for the SK 9000 A1-A4?

The primary compatible receiver is the Sennheiser EM 9046. The SK 9000 also operates with the EM 6000 and EK 6042 when those receivers are set to Long Range (LR) mode.

Q: Is AES 256 encryption available on the SK 9000?

Yes, AES 256 encryption is optionally available on the SK 9000, making it suitable for secure broadcast, legal proceedings, or confidential corporate presentations where signal interception is a concern.

Q: How does the SK 9000 handle battery life?

The SK 9000 uses either the BA 61 rechargeable lithium-ion battery pack or the B 61 battery case (two AA batteries), both sold separately. Battery status is displayed on both the transmitter and the EM 9046 receiver for remote monitoring.

Q: Can the SK 9000 be used with lavalier microphones from other brands?

The SK 9000 accepts lavalier microphones wired to a 3-pin SE (Lemo-style) connector. Third-party lavalier mics with compatible connectors or adapters can be used, but Sennheiser-brand lavalier mics such as the MKE series are recommended for optimal performance within the Digital 9000 system.

Q: What makes the Digital 9000 frequency grid intermodulation-free?

The Digital 9000 system places transmitters on an equidistant frequency grid, meaning channels are evenly spaced rather than selected ad hoc. This spacing eliminates intermodulation products — the spurious signals generated when RF frequencies mix — allowing far more simultaneous channels than analog systems of comparable bandwidth.