The microphone way

The microphone way by air
One way is to stick the player to a microphone stand and point a good quality microphone at the instrument.
A variation is to stick a mini microphone directly to the violin. The microphone can be a dynamic moving coil type or condenser studio microphone. Either type cost according to quality.

This 1970´s dynamic Sennheiser 421 microphone is still among the best.

Pro´s: The sound quality can be very good, if the player is experienced,  stays close to the mike (within a few inches), avoids breathing too hard or making other sounds and stays relatively distant from other players, so the microphone is not picking up their sounds, too. Of course, the others should not play too loud, either. You can also talk or sing into it, as well. Good for studio recordings, where you are in your own personal space.

Con´s: Good microphones are fragile. Less good for live events, as the microphone really needs a soundperson to control the sound, as you cannot know how the sound blends in with the rest, heard from the audience´s position. Unless you are playing alone, your fellow musicians may bleed through to your microphone as well. The microphone also picks up wind blasts, and can cause the dreaded feedback howls. It´ll really turn off your audience.