Ten common problems of wireless microphone solutions (part two)

The performance of the wireless microphone is often affected by various factors such as the frequency interference of the surrounding equipment, improper operation of the user, etc., and various failures occur. Next, the microphone manufacturer-Guanxing Electronics will teach you how to avoid and prevent Common wireless microphone problems.

6: Man-made wireless signal is blocked

The human body may also interfere with wireless signals. The human body is mainly composed of a large amount of water and can absorb radio frequency energy. In addition, if the user wraps his hand around the external antenna of the handheld transmitter, its effective output can be reduced by more than 50%. Similarly, if the flexible antenna on the transmitter is curled or folded, the signal will also be affected.

Solution: Keep the transmitter antenna fully expanded and unblocked to achieve a larger range of signal transmission to achieve better performance.

7: The battery voltage of the transmitter is not enough

The battery life of the transmitter is the primary concern of wireless microphones, and users always try to reduce the cost of the device through low-cost batteries. Most wireless manufacturers specify alkaline batteries or disposable lithium batteries because their output voltage is relatively stable throughout the battery life cycle. This is very important, because most transmitters will experience acoustic signal distortion or signal loss under low voltage conditions. Rechargeable batteries often seem to be the ideal solution, but most rechargeable batteries, even if they are fully charged, provide a voltage that is 20% lower than that of disposable batteries.

Solution: In order to solve the battery problem, carefully compare the voltage output requirements of the transmitter battery at any time to ensure the sustainability of the battery during the entire working process. Lithium-ion batteries and rechargeable alkaline batteries usually can work continuously, while nickel-metal hydride and nickel-cadmium batteries may only last a few hours. This is especially true for 9-volt batteries, AA rechargeable batteries have similar performance to disposable AA batteries.

8: Non-adjustable transmitter

The inherent noise and limited dynamic range of FM transmission make analog wireless audio transmission have its limitations. To overcome this, most wireless microphone systems usually use two audio processing methods to improve sound quality. Add pre-emphasis equipment to the transmitter and de-emphasis equipment to the receiver to improve the signal-to-noise ratio of the signal. The compressor and receiver extender in the transmitter can increase the dynamic range by more than 100dB. This makes the volume setting very important. If the audio level is too low, a hissing sound will be produced; if it is too high, it may cause distortion.

Solution: To obtain better sound quality, the input gain of the transmitter should be adjusted so that global modulation occurs when a higher volume is generated, but without distortion.

9: Wireless system settings

The troublesome problem with wireless systems is that the waves themselves are constantly changing. Since the transition to digital TV, the waves of analog and digital TV channels have continued to change. The FCC is trying to find a way to make consumer products (personal PDAs, smart phones or home devices) use vacant TV channels for wireless Internet access.

Solution: It used to be easy to know whether the VHF band TV channel of the city where the user is located is odd or even. However, now when people install and use wireless microphones (and in-ear monitors and intercom systems, etc.), they must regularly check the local spectrum conditions even when working in a venue they are familiar with.

Of course, this is far less complicated than we thought. First of all, most wireless equipment manufacturers can now provide online frequency selection tools to synchronize updates with newer TV channels. Secondly, both external RF scanners and spectrum analyzers can quickly scan the entire spectrum (including TV bands), and are becoming more powerful and cheaper, providing a more practical choice for those who rely heavily on wireless systems. . After that, the wireless system itself has gradually become more complicated. Even some entry-level systems can scan the spectrum or find an open spectrum. Some high-quality systems can even be connected to your PC or Mac, scan the spectrum, give you an intuitive RF status description, and calculate a set of better frequencies (considering other RF equipment), and then automatically set the reception Device.

10: The receiver output level is set incorrectly

With so much discussion on frequency, wavelength and antenna, it’s easy to overlook the basic requirements of a wireless microphone system: In order to replace the connection cable between the signal source and the audio system, the receiver is usually equipped with an output level control, and most The wired microphone does not. This provides a better opportunity for finer matching between the output of the receiver and the input.

Solution: Regardless of the microphone level or the line level, the output level should be set to a practicable higher level, while not exceeding the limit of the audio system input, which may be indicated on the input channel of the mixer , Can also be judged by listening to the sound distortion.