The transmission power of wireless microphones is usually between 10 and 50 milliwatts, with 30 milliwatts being the most common.
For example, many models in SHURE’s PGX series have a transmission power of 10 milliwatts, while the UR series can be adjusted between 10 and 50 milliwatts.
Sennheiser’s EW series is typically set at 30 milliwatts, and AMSAUDIO’s TC series also operates at 30 milliwatts.
The choice of transmission power is mainly influenced by the following factors:

1. Regulatory Restrictions

• National regulations: Different countries have varying rules regarding the transmission power of wireless devices. To avoid interference with other wireless systems (such as Wi-Fi, Bluetooth, and other radio communications), many countries impose limits on the maximum transmission power of wireless microphones.
  This means that the same microphone model may have different transmission power settings in different countries, in order to comply with local laws and regulations.

• Spectrum management: Radio spectrum is a limited resource. Higher transmission power can cause congestion and interference within the spectrum, so many countries enforce strict spectrum management policies to limit the transmission power of wireless devices.

2. Battery Life

• Power consumption and endurance: Transmission power directly affects the power consumption of wireless microphones.
  Higher transmission power means faster battery drain, resulting in shorter operating time. For many applications—such as performances and conferences—continuous operation is essential.
  Therefore, an appropriate transmission power level is typically chosen during design to ensure long-term stability during use.

• Cost-effectiveness: A transmission power of 30 milliwatts is considered an optimal and economical balance—it provides good audio quality while meeting the needs of most usage environments.
  In most cases, this power level offers a satisfactory transmission range and sound quality without excessively consuming battery life.

3. Signal Coverage and Audio Quality

• Transmission range: Although increasing transmission power can extend the transmission distance, it is not the only solution.
  Wireless microphone performance depends on the entire system design, including antenna coverage, receiver sensitivity, and environmental conditions.
  With proper system planning, moderate transmission power can still achieve ideal signal coverage.

• Signal interference: Higher transmission power can increase the likelihood of intermodulation interference, especially in environments with many wireless microphones in use.
  In such cases, using lower transmission power can reduce interference risks and improve transmission reliability.

4. Technological Advancements

• Digital technology: With the development of digital wireless technology, improvements in audio compression and digital signal processing have made it possible to achieve high-quality audio transmission even at lower power levels.
  This allows devices to maintain excellent sound quality and stability without increasing power consumption.

Conclusion

In summary, the design of wireless microphone transmission power is the result of a comprehensive consideration of regulatory limits, battery life, signal quality, and technological advancements.
Although increasing transmission power may improve coverage in some cases, in practical applications, choosing an appropriate power level (such as 30 milliwatts) offers the best balance between performance and practicality, ensuring users experience clear and stable audio transmission in various environments.