If you run a school or organization and you have a computer lab, we recommend using headsets when you use ScoreNexus. (We always recommend headsets because students will use them on the real TOEFL, but it is especially important to use them in loud environments.)
A simple, cheap solution we found is to use one of these adapters, which you can find at an electronics shop:
This will allow your students to use headsets that comes with iPhone/Android smartphones and many other devices. This is a lot easier and cheaper than trying to buy the large headsets that are made to be used with computers (which also often break).