JTS SIEM-121 System | UHF Wireless In-Ear Monitor | 300m Range with Bodypack Receiver

JTS SIEM121  (JTS IEM Siam 121)

UHF Wireless In-Ear Monitoring System

The JTS SIEM-121 System is a UHF PLL wireless in-ear monitoring solution designed for musicians, vocalists, and live performers who need reliable personal audio monitoring on stage. Combining the SIEM-121T single-channel stereo (or dual-channel mono) wireless transmitter with the compact SIEM-121R bodypack receiver, the system provides up to 300 meters (984 feet) of wireless coverage, flexible stereo/mono monitoring, and convenient frequency management for live performances and stage productions.

JTS SIEM-121 System Competitive Differences

• Up to 300 Meters of Wireless Coverage: Provides an extended operating range of up to 984 feet for performers working across large stages and venues.
• Flexible Frequency Management: Features 6 programmable groups with up to 24 channels per group for wireless system configuration.
• Digital Volume Adjustment: Offers adjustable audio levels from -40 dB to +20 dB for precise monitoring control.
• Stereo and Mono Operation: Supports multiple monitoring configurations to accommodate different performance requirements.
• Remoset Functionality: Provides convenient wireless synchronization of compatible transmitter and receiver settings.
• Durable Metal Construction: Rugged all-metal construction is designed to withstand regular use in demanding performance environments.
• Extended Battery Operation: The SIEM-121R bodypack receiver provides over 8 hours of operation using two AA batteries or compatible rechargeable batteries.

JTS SIEM-121 System Description

The JTS SIEM-121 System delivers a flexible wireless monitoring solution for performers who need to hear their personal audio mix without being restricted by traditional wired connections. Its UHF PLL wireless design provides dependable signal transmission, while the stated operating range of up to 300 meters makes it suitable for a variety of stage sizes and live performance applications.

The SIEM-121T wireless transmitter features two balanced XLR/6.3mm combo audio inputs, allowing connection to compatible mixing consoles and other professional audio equipment. Two balanced 6.3mm loop outputs provide additional signal-routing flexibility, while a front-panel 6.3mm stereo headphone output allows convenient monitoring at the transmitter. Digital volume adjustment from -40 dB to +20 dB and selectable stereo/mono operation provide control over monitoring configurations.

The compact SIEM-121R bodypack receiver is designed for comfortable use during live performances. Featuring a 3.5mm stereo earphone output rated at 60 mW, the receiver supports personal in-ear monitoring with a minimum load impedance of 16 ohms. Its LCD provides information including RF and audio signal levels, battery status, operating frequency, group/channel selection, and limiter settings. The receiver operates for over 8 hours using two AA batteries or compatible NiMH rechargeable batteries.

For productions requiring organized wireless frequency management, the system supports 6 programmable groups with up to 24 channels each. User-programmable names, key-lock functionality, and Remoset synchronization help simplify system configuration and day-to-day operation. With its durable construction and versatile audio connections, the SIEM-121 System is well suited for vocalists, instrumentalists, bands, houses of worship, and live sound applications.

SIEM-121 System Features

• Complete UHF PLL wireless in-ear monitoring system with SIEM-121T transmitter and SIEM-121R bodypack receiver
• Wireless operating range of up to 300 meters (984 feet)
• 6 programmable frequency groups with up to 24 channels per group
• Digital volume adjustment from -40 dB to +20 dB
• Selectable stereo and mono monitoring modes
• Remoset functionality for convenient system synchronization
• User-programmable names for system identification
• Rugged all-metal construction
• Two balanced XLR/6.3mm combo transmitter inputs
• Two balanced 6.3mm transmitter loop outputs
• 6.3mm stereo headphone monitoring output on transmitter
• Compact bodypack receiver with 3.5mm stereo earphone output
• Receiver LCD displays RF level, audio level, battery status, frequency, and operating settings
• Receiver includes HF booster and limiter settings
• Key-lock functionality helps prevent accidental setting changes
• Over 8 hours of receiver operation with two AA batteries or compatible NiMH rechargeable batteries
• Transmitter supports 100–240V AC power input

SIEM-121 System Specifications

• System Type: UHF PLL Wireless In-Ear Monitoring System
• Transmitter Model: SIEM-121T
• Receiver Model: SIEM-121R
• Published Carrier Frequency Range: 470–960 MHz (specific operating frequencies depend on system version)
• Wireless Operating Range: Up to 300 m (984 ft)
• Programmable Groups: 6
• Channels Per Group: Up to 24
• Digital Volume Adjustment: -40 dB to +20 dB
• Monitoring Modes: Stereo / Mono

SIEM-121T Transmitter Specifications

• Transmitter Type: UHF PLL Single-Channel Wireless Transmitter
• Carrier Frequency Range: 470–960 MHz (published range)
• RF Output Power: 10 mW
• Nominal Frequency Deviation: ±40 kHz Maximum
• Audio Input Impedance: 20 kΩ
• Nominal Input Level: -12 dBu
• Maximum AUX Input Level: +12 dBu
• Maximum LINE Input Level: +22 dBu
• Audio Inputs: 2 x Balanced XLR / 6.3mm Combo Connectors
• Audio Output: 1 x 6.3mm Stereo Headphone Jack
• Loop Outputs: 2 x Balanced 6.3mm Jacks
• LCD Display Functions: Key Lock, Stereo/Mono, RF Power, User Name, Group/Channel, Frequency, Input Selection, Sensitivity, Remoset ID
• Power Supply: 100–240V AC Switching Power Supply
• Dimensions (W x D x H): 8.27 x 1.65 x 8.86 in (210 x 42 x 225 mm)
• Weight: 2.51 lb (1.14 kg)

SIEM-121R Receiver Specifications

• Receiver Type: UHF PLL Bodypack Receiver
• Carrier Frequency Range: 470–960 MHz (published range)
• Earphone Output Power: 60 mW
• Minimum Load Impedance: 16 Ω
• Earphone Output Connector: 3.5mm Stereo Jack
• Battery Type: 2 x AA Batteries or 2 x NiMH Rechargeable Batteries
• Battery Operating Time: Over 8 Hours
• LCD Display Functions: Antenna, RF Level, AF Level, User Name, Key Lock, Battery Level, Stereo/Mono, HF Booster, Limiter, Group/Channel, Remoset ID, Frequency
• Dimensions (W x D x H): 2.56 x 0.79 x 3.74 in (65 x 20 x 95 mm)
• Weight: 4.59 oz (130 g) Without Batteries