LECTROSONICS UM400-BLK21 Belt Pack Transmitter Block 537.6-563.1 1.6MHZ 100KHZ

( Brand: Lectrosonics ), ( Manufacturer Part Number: UM400-BLK21 ), ( Part Type: Belt Transmitter Block ), ( Maximum Spl: Receiver ), ( Country Of Origin: United States )

Review LECTROSONICS Um400 Belt Pack Transmitter Block 537.6-563.1 1.6mhz 100khz

The **Lectrosonics UM400-BLK21 Belt Pack Transmitter** is a high-performance, wireless audio solution designed for professional applications where reliability, clarity, and durability are paramount. Part of Lectrosonics renowned UM400 series, this compact and rugged transmitter operates in the **537.6 563.1 MHz** frequency range, offering seamless integration into professional audio workflows with its **1.6 MHz** channel spacing a standard that ensures minimal interference and optimal signal integrity. The UM400-BLK21 is specifically engineered as a **belt-pack unit**, making it ideal for on-stage or in-field use where portability and ease of access are critical. Its robust construction is built to withstand the demands of live performances, broadcast, and studio environments, featuring a durable enclosure that protects against dust, moisture, and physical stress.

This transmitter operates in **100 kHz** mode, delivering a clean, high-fidelity audio signal with low latency, making it suitable for applications requiring precise synchronization, such as live sound reinforcement, theater productions, or broadcast commentary. The UM400-BLK21 is part of Lectrosonics **Block 21** frequency allocation, a globally recognized standard that minimizes the risk of signal collisions, ensuring stable performance even in crowded RF environments. Its compact design allows for easy attachment to a belt or harness, freeing the user s hands while maintaining quick access to essential controls, including power, transmit, and channel selection. The unit s **plug-and-play compatibility** with Lectrosonics extensive range of receivers ensures seamless integration into existing wireless audio systems, whether for solo vocalists, instrumentists, or multi-channel setups.

Beyond its technical specifications, the UM400-BLK21 stands out for its **low power consumption**, extending battery life for extended use without the need for frequent recharging. Its **digital signal processing** capabilities further enhance audio quality by reducing noise and distortion, while its **frequency-hopping spread spectrum (FHSS)** technology provides an additional layer of interference resistance. Whether deployed in a live concert, theater production, or broadcast setting, this transmitter delivers the reliability and clarity professionals demand, making it an indispensable tool for those who require wireless audio solutions they can depend on.

### **Pros and Cons of buying a Lectrosonics UM400-BLK21 (UM400 Belt Pack Transmitter)**

1. **High-Quality Wireless Audio Transmission**

The UM400 system is a professional-grade wireless microphone transmitter known for its reliability and low-latency performance. It uses Lectrosonics proprietary **UM400 protocol**, which is optimized for broadcast, live sound, and studio applications where crystal-clear audio is critical.

2. **Wide Frequency Range (537.6 563.1 MHz)**

The UM400 operates in the **UHF band**, which is less prone to interference from consumer devices (unlike lower-frequency systems). This makes it ideal for environments with many wireless devices, such as large venues, festivals, or studios with multiple wireless mics.

3. **1.6 MHz Channel Width**

A wider channel width (compared to standard 200 kHz or 300 kHz systems) allows for **higher audio fidelity and better noise rejection**. This is particularly useful in noisy environments where maintaining clean audio is essential.

4. **Belt Pack Form Factor**

The **UM400 Belt Pack** is a compact, wearable transmitter designed for **singers, speakers, or performers** who need hands-free operation. It is lightweight and discreet, making it suitable for extended wear.

5. **Compatibility with Lectrosonics Ecosystem**

The UM400 works seamlessly with other Lectrosonics receivers (e.g., UM400 receivers, UM400 systems) and accessories like **UM400 receivers, wireless systems, and mixing consoles** that support Lectrosonics protocols.

6. **Low Latency & High Dynamic Range**

Lectrosonics systems are known for **minimal delay** and **excellent signal-to-noise ratio**, making them ideal for applications where timing and clarity are crucial (e.g., live vocals, broadcast, or studio recording).

7. **Durability & Build Quality**

Lectrosonics equipment is built to withstand **professional use**, including rough handling, temperature variations, and extended battery life. The UM400 is no exception, making it a long-term investment.

8. **Professional-Grade Features**

- **Automatic Gain Control (AGC)** helps maintain consistent audio levels.

- **Low-power operation** extends battery life.

- **Secure frequency assignment** reduces the risk of interference.

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1. **High Cost**

The UM400 is an **expensive** piece of equipment, especially when compared to consumer-grade wireless mics or budget professional systems. The **UM400-BLK21 Belt Pack alone** is likely to cost **$1,000 $1,500 **, depending on the market and whether it s new or used.

2. **Requires a Matching Receiver**

You cannot use the UM400 Belt Pack alone it must pair with a **compatible UM400 receiver** (or a system that supports UM400 protocol). This adds to the initial investment.

3. **Limited Compatibility Outside Lectrosonics Ecosystem**

Unlike some wireless systems that work with third-party receivers, the UM400 is **Lectrosonics-exclusive**. If you re already invested in a different brand (e.g., Sennheiser, Shure, or Audio-Technica), switching may not be cost-effective.

4. **Complex Setup for Beginners**

Lectrosonics systems require **proper frequency assignment and pairing**, which can be intimidating for users unfamiliar with wireless audio protocols. Some setup may involve **software or manual configuration**.

5. **Battery Life Considerations**

While the UM400 is efficient, **battery life depends on usage**. For long performances, you may need **spare batteries or a battery pack**, adding to operational costs.

6. **Potential for Interference in Dense Environments**

Although the UHF range reduces interference, **large venues with many wireless devices** (e.g., multiple mics, cameras, or other transmitters) can still cause signal conflicts. Proper frequency planning is necessary.

7. **No Built-in Diversity Reception**

Unlike some advanced wireless systems, the UM400 does not feature **diversity reception** (multiple antennas to combat multipath interference). This could be a drawback in **highly reflective environments** (e.g., large halls with metal structures).

8. **Used Market Reliability Concerns**

If purchasing a **used UM400**, there is a risk of **damaged internals, worn-out batteries, or outdated firmware**. Always inspect the unit thoroughly or buy from a reputable dealer.

---

### **Conclusion & Recommendation**

#### **Who Should Buy the Lectrosonics UM400-BLK21?**

- **Professional vocalists, speakers, or performers** who need **reliable, high-fidelity wireless audio** in demanding environments.

- **Broadcast, live sound, and studio professionals** who require **low-latency, interference-resistant wireless transmission**.

- **Users already invested in Lectrosonics equipment** (e.g., receivers, consoles) and want seamless integration.

- **Applications where cost is not a primary concern**, and **long-term durability** is valued over budget options.

#### **Who Should Avoid It?**

- **Beginners or hobbyists** who are not ready for a high-end wireless system.

- **Budget-conscious buyers** who can achieve similar results with **mid-range wireless mics** (e.g., Sennheiser G4, Shure BLX, or Audio-Technica ATW-1100).

- **Users who need maximum flexibility** (e.g., switching between different wireless brands).

- **Those working in very small or controlled environments** where interference is minimal (a simpler system may suffice).

If you are a **professional in need of a robust, high-performance wireless microphone system** and can justify the cost, the **Lectrosonics UM400-BLK21 is a superior choice**. Its **reliability, audio quality, and professional-grade features** make it one of the best wireless transmitters available.

- **Sennheiser G4 (G4-2000)** High-end but slightly more affordable.

- **Shure BLX Series** Reliable and widely compatible.

- **Audio-Technica ATW-1100** Good balance of performance and cost.

You need **the best professional wireless audio possible**.

You are already in the **Lectrosonics ecosystem**.

You prioritize **durability, low latency, and interference resistance**.

You are a **casual user or hobbyist**.

You need **maximum flexibility across brands**.

You can achieve similar results with a **more affordable system**.

Details:

Excellent - Minor surface blemishes that can be seen, but not felt. Good - Small Scratches, minor scuffing. As-Is - Major scratches, dents, discoloration or cracks; Broken off missing panels. Any other parts/power adapters or accessories that are NOT shown in the pictures included.

Fair - Medium scratches, scuffing or denting; Damaged missing small plastic trim panels.

part #: um400blk21 prices

• $350.00-$586.99

specifications micwisys:

• brand: Lectrosonics
• mpn: Um400-blk21
• part type: Belt Transmitter Block
• maximum spl: Receiver
• country of origin: United States

general micwisys:

• condition: Used
• Musical Instruments Gear > Pro Audio Equipment > Microphones Wireless Systems

offer micwisys:

• sold: 0
• quantity: 1
• started: May 15, 2026
• options: Ship-to-home
• best offers: True
• availability: In Stock

seller micwisys:

• # reviews: 7741
• rating: 99.8%
• city: Santa Ana, California

payments micwisys:

• wallet: Paypal
• other
• credit card: Mastercard

returns micwisys:

• paid by: Seller
• method: Money back
• policy: Returns Accepted
• time: 30 Days

shipping micwisys:

• class: Standard
• carrier: FedEx
• type: Fixed
• transit: 4-8 Days
• cost: $0.00
• service: FedEx Ground / FedEx Home Delivery

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