I am planning on doing some classroom recordings for later transcription of second language users. As this will be done with separate groups of students using their second language during a class, a mic that captures clear sound is needed. Can anyone share their experience with different types or specific brands of microphones?
The quality speech recording is only possible when the microphone is fixed relatively close to your mouth, so you should use a headset (frequently called madonna, e.g. https://www.handheldaudio.co.uk/shop/proel-hcm08pro-headworn-microphone-beige/ ) and the pocket recorder (e.g. Tascam brand). Also you can use a clip microphone fixed to your clothes. But if you need a loud speech support for big auditorium, you need wireless box in your pocket and the output is then going in parallel to recording device and to loudspeaker system. Then madonna is better as clip microphone is more sensitive for positive feedback from loudspeakers. The nowadays digital processing audio systems has possibility to suppress feedback problems very efficiently. You should carefully tune the system gain to have clear and strong record, but not clipped (overloaded, distorted) on other hand.
It depends a bit on how many students there are in a group. If there are only five or six, clustered round a single microphone, an omni might be OK, but they pick up reverberation like anything. For larger groups, and especially in rooms prone to echo, at leat two cardioid microhones would be better. You could use more. Headset are good, but of course you need a large mixer to cope with many microphone inputs, one per student.
The golden rule is to keep the distance from microphone to student as short as practicable.
