What do recordings in both analog and digital formats start with?

Recordings in both analog and digital formats begin with sound. Sound is a form of mechanical wave that is generated by vibrating objects and propagates through various mediums, such as air, water, or solids.

In the context of recordings, microphones are used to capture sound waves. These sound waves are then converted into electrical signals, which represent the sound in a form that can be recorded. In analog recordings, this involves capturing continuous waveforms, while in digital recordings, the sound is sampled and converted into a series of discrete values.

While microphones, electrical signals, and computer interfaces play significant roles in the recording process, they each follow the initial step of starting with sound. Therefore, sound serves as the fundamental element that initiates the entire recording process, making it the correct answer to the question.