Sennheiser HMD 27 Professional Closed-Back Broadcast Headset

Circumaural Broadcast Standard: Sennheiser HMD 27

The Sennheiser HMD 27 broadcast headset is crafted for broadcast commentators, audio engineers, and intercom operators who demand total acoustic isolation and pristine voice clarity in noisy live event environments.

Combining full over-ear passive noise attenuation with Sennheiser’s broadcast transducer technology, the HMD 27 provides comfortable, fatigue-free wearing over long production hours. Available now in our Sennheiser pro audio store catalog, this modular headset combines ActiveGard hearing protection with flexible modular cabling to integrate seamlessly into any broadcast desk or OB van ecosystem.

Key Features & Pro-Level Advantages

• Closed-Back Circumaural Isolation: Over-ear acoustic design delivers up to 32 dB of passive noise attenuation, shielding operators from ambient stadium, crowd, and control room sound.
• Noise-Compensated Hypercardioid Microphone: Dynamic BMD 424 capsule focuses strictly on the commentator’s voice while suppressing off-axis ambient noise (40 Hz – 16,000 Hz).
• Innovative Split Headband Design: Two-piece automatic headband padding spreads apart to relieve top crown pressure during long production shifts, or can be clicked together as a standard headband.
• Switchable ActiveGard Hearing Protection: Automatically protects operator ears against sudden signal bursts and acoustic feedback peaks above 105 dB without clipping sound transmission.
• Reversible 360-Degree Boom Arm: Dynamic microphone boom arm can be positioned on either the left or right ear side with tactile click-stop adjustment.
• Modular Cable Architecture: Uses Sennheiser’s Cable-II series with built-in coiled strain relief to eliminate mechanical cable-handling noise.

Key Technical Specifications

• Device Type: Professional Over-Ear (Circumaural) Closed-Back Broadcast Headset

• Headphone Transducer Principle: Dynamic, Closed-Back

• Headphone Frequency Response: 8 Hz – 28,000 Hz

• Headphone Nominal Impedance: 64 Ohms

• Sound Pressure Level (SPL): 115 dB SPL (1 kHz / 1 mW) / 128 dB Max SPL

• Passive Ambient Noise Attenuation: Up to 32 dB

• Microphone Type: Dynamic, Noise-Compensated (BMD 424 Capsule)

• Microphone Polar Pattern: Hypercardioid

• Microphone Frequency Response: 40 Hz – 16,000 Hz

• Microphone Output Voltage: 0.5 mV/Pa at 1 kHz

• Hearing Protection: ActiveGard (Switchable On/Off, > 105 dB peak limiting)

• Headband Mechanism: Auto-expanding split headband system (convertible to single band)

• Weight (w/o cable): Approx. 240 g (8.5 oz)

• Color: Black

Compatibility & System Integration

• Broadcast & Intercom Integration: Fully compatible with production intercom consoles (RTS, Riedel, Clear-Com, Glensound), commentary units, field production mixers, and camera control units.

• Modular Cable Options: Works with Sennheiser Cable-II quick-disconnect system—choose Cable-II-X3K1 (XLR-3M + 1/4″ TRS), Cable-II-B4 (4-pin XLR female), Cable-II-B5 (5-pin XLR male), or Cable-II-0 (bare ends).

• Replacement Parts: User-replaceable soft circumaural ear cushions, headband padding strips, MZW 45 foam windscreens, and Cable-II series connection leads.

• Box Contents: 1x Sennheiser HMD 27 headset, 1x foam windshield (MZW 45), 1x headband padding element (for single-piece conversion), 1x cable clip, quick start guide. (Note: Cable-II sold separately or bundled per variant).

• System Expansion: Browse matching Sennheiser broadcast wireless units, beltpacks, and studio monitoring gear on our dedicated Sennheiser Brand Store.