(Dont forget to stan nct and loona ^3^)
Ok, so A .T. Box is an audio-only device that rapidly scans through multiple audio channels that is said to make it relatively easy for ghosts to manipulate to say a word or phrase in real time. It has been proven that sounds other than spoken language be captured on the spirit box and is usually discovered as something other than what is surrounding the investigator.
While the use of a spirit box will make it evident to be quite loud, it is recommended to remain silent when beckoning for responses in paranormal investigations as some evidence can be difficult to hear without audio-editing.
So far, the only common default sound heard from the spirit box when no response is given is that of static with minute pauses that spread every sound of static about a second long at best, and whenever audio messages have been captured, it becomes most obvious as the static will either become distorted or will completely die out for the duration of the foreign sound(s).