Solar panels themselves are completely silent; however, certain pieces of equipment on a solar farm do emit sound. Transportation and maintenance equipment—including cars, trucks, lawnmowers, and string trimmers—is a common source of noise on solar farms that most people are used to hearing elsewhere. In addition to these sources, inverters and transformers on a solar farm will generate low levels of sound. A study in 2014 conducted at a solar facility in Australia determined that direct noise from the solar facility experienced at nearby residences would reach only 30 dBA, which is around the ambient noise level at night in a rural area. This indicates that any noise from the solar inverters would be imperceptible to nearby residents.