CompuServe Messages

Sandra, Wireless microphones are available from a variety of sources. I have experience with two suppliers and literature from several others. The first unit was made by Azden. The audio quality was not suitable for my application. There was noise present which could be easily heard when the talent quit speaking. The signal to noise ratio was significantly worse than my S-VHS camera. The unit was returned to Azden. They found that it met or exceeded their specifications. My dealer, Video Direct, was kind enough to let me exchange it for other merchandise. Working with a good dealer is important. Since then, I have purchased an Audio Technica Pro 88W which has W88-68-830 on the box. I believe that the microphone element is specified by the 830. The difference between these units is substantial. The fidelity and signal to noise ratio is much improved. I am an electrical engineer, but have not CRITICALLY analyzed either of these units with anything except my ears. I did take a quick look at the output of both systems with an oscilloscope. With the Azden, I could see on the scope what I heard with my ears. With the Audio Technica, I could see very low level noise which confirmed that the scope was working correctly. I could not hear any noise. My hearing is damaged. My wife finds the Pro 88W audio quite acceptable. The application for each unit has been limited to 50 feet. The first unit exhibited the noise problem at less than 20 feet. In a room full of people, I have occasional dropouts with the Pro 88W. Telex makes a diversity system which sells for about $600. I will probably buy one. The Pro 88W was $232 list. I think it is a good value. One thing you may run into, television stations can interfere with VHF wireless microphones. If you know the channels in use in your area, the manufacturer of the microphone should know which microphone channels to avoid. Another problem I have seen is caused by digital noise produced by my camera. It radiates radio frequency energy as do all clocked digital circuits. One of the microphone receivers was able to pick up a "birdie" from the camera which interfered with the reception. That is NOT the fault of the microphone or receiver. It is just a fact of life; even well designed digital devices radiate rf energy. At very short distances, a weak birdie can be a significant problem. The receiver must be mounted on the camera. Switching frequencies is the solution. Most wireless microphone manufacturers produce products for more than one frequency of operation. Larry Kunk