Radio networks, news agencies, all-news radio stations, and many other radio stations have reporters in the field interviewing newsmakers and members of the public, and reporting on what is happening locally, nationally, and internationally. Concerts and other live events are often recorded in the field at the same time that they are being performed in front of an audience. There are many other types of location situations. The main sound problems the people are likely to encounter when the people are on location are those that come from everything else that is happening at the location. Some of the problems common to location sound recording can be solved by surveying the location ahead of time. The main recorders used for location work are the small portable ones that record on hard drive or memory cards. More complicated mixers are used for club performances and mixing band or orchestra music.
Hum is a low-frequency problem associated with leakage of the 60 hertz AC electrical current into the audio signal. A poor ground in an electrical circuit can cause hum. Attenuating frequencies right around 6oHz would lessen the problem.