Shure BLX14/SM31-H11 Wireless Fitness Headset System

The Shure BLX14/SM31-H11 is a complete analog wireless headset system built for fitness instruction, active presentation, and other voice applications where freedom of movement matters. It combines the BLX4 tabletop receiver, BLX1 bodypack transmitter, and SM31FH cardioid fitness headset microphone in one coordinated package. The H11 version operates in the 572–596 MHz frequency band, so buyers should verify local frequency authorization before use.

This system helps instructors communicate clearly without being tethered to a mixer or sound system. Its SM31FH headset uses a cardioid condenser capsule with a tailored vocal response, helping focus on the speaker while reducing unwanted surrounding sound. The flexible boom lets the user position the capsule close to the mouth for consistent voice pickup during movement.

The moisture-repellent SM31FH is designed for humid, high-energy environments such as aerobics studios, training floors, and fitness classes. Its lightweight wireframe headset is made to stay in place during active use, while the included windscreen helps reduce breath, wind, and plosive noise. The BLX1 bodypack provides up to 14 hours of operation from two AA alkaline batteries.

For wireless performance, the BLX platform provides a stated line-of-sight operating range of up to 300 feet. The BLX4 receiver uses microprocessor-controlled internal antenna diversity and QuickScan frequency selection to help locate an open frequency. Front-panel LEDs show system readiness and incoming audio level, including overload indication.

The BLX14/SM31-H11 connects easily to a PA system, powered speaker, mixer, or amplifier through its balanced XLR microphone output or 1/4-inch instrument-level output. It is a practical standalone voice system for a single instructor, and the BLX platform supports up to 12 compatible systems per frequency band depending on region and RF environment. Additional Shure TQG-equipped headset, lavalier, earset, and instrument options can also be used with the BLX1 bodypack.

Key Features

• H11 UHF Band: Operates from 572 to 596 MHz for matched H11 wireless components.
• Complete Wireless System: Includes BLX4 receiver, BLX1 bodypack, and SM31FH headset microphone.
• Fitness-Ready Headset: Hydrophobic microphone construction helps resist moisture-related corrosion in active environments.
• Up To 300-Foot Range: Provides up to 91 m / 300 ft line-of-sight operation.
• Long AA Battery Life: BLX1 runs up to 14 hours on two AA alkaline batteries.
• QuickScan Setup: Receiver scan function helps identify an available group and channel.

Design & Installation

The BLX4 receiver and BLX1 transmitter use molded ABS housings suited to regular portable sound use. The SM31FH combines a lightweight wireframe headband, flexible gooseneck, hydrophobic cartridge protection, and a TA4F connector. A clothing clip and windscreen are included for securing and positioning the headset microphone.

Place the BLX4 receiver near the mixer, PA system, powered speaker, or amplifier, then connect it using the XLR microphone output or 1/4-inch instrument output. Use the receiver scan function, match the BLX1 group and channel to the receiver, install the supplied AA batteries, and set bodypack gain for normal green audio indication. Keep transmitter and receiver within line of sight where possible, match all wireless components to the H11 band, and confirm local spectrum authorization before operation.