The audio equipment, amplifier, mixer board(s), equalizer, etc were typically located in the sound booth toward the rear of the building. However, the wireless receiver, by necessity was located on or near the stage. This arrangement presented a problem for the audio engineers responsible for providing good sound quality. If an adjustment was deemed necessary to the wireless receiver, such as the MUTE level or VOLUME level, the sound operator would have to oftentimes walk from the back of the building and ‘sneak’ on-stage to make the adjustments. I remember seeing grown men crawling on their stomachs trying to reach the on-stage wireless receiver without being noticed by the audience, sometimes several times during a single sermon, speech, lecture or event. I noticed them because I was watching, but most of the crowd didn’t appear to notice. In the early days, the MUTE level was an adjustment on most equipment. Each geographic location experiences a different level of radio-frequency back ground noise, static if you will, both natural and man made. The MUTE knob was intended to set a threshold at which the static would ‘be quiet’. Another way of saying this is that if the signal from the microphone/transmitter unit because weak, either due to a low battery, or more likely due to the lecturer walking too far away from the wireless receiver, the MUTE circuit would activate and protect the audience from a barrage of static blasting through the speakers. In rural country environments, the MUTE level could be set once or twice and suffice for the entire event. However, in city environments, the back-ground static level changes frequently due to radio transmitters from a wide variety of sources, taxis, police, wireless phones, radios, etc. City environments often required adjusting the MUTE knob more carefully and more often than rural environments.
Regarding the VOLUME control on the wireless receiver, after a good sound-check, an agreeable level could be selected. Usually, the audio engineer operating the sound-booth could also adjust the volume through the mixing board located in the sound room at the rear of the building. So, with proper preparation and sound-checks, the VOLUME knob on the wireless receiver could be set and left alone, most of the time. However, problems arose when the VOLUME knob was set to handle a loud-booming voice of a particular lecturer or pastor, but then the wireless microphone was handed to another person of lesser vocal loudness. If the audio engineer had anticipated such an occurrence, the VOLUME knob on the wireless receiver could have been set accordingly. However, oftentimes the wide difference in dynamic audio range from person to person would require that one of the audio-engineers, crawl along his/her belly while trying to avoid detection by the audience, while adjusting the VOLUME knob of the on-stage wireless receiver.