Hi Takeshi,
There have been a lot of good suggestions already: unidirectional microphones, sound-insulated ear cups – standard with digital audio lab head phones (I thought I had
seen it all in the digital audio lab, but haven’t had a chance to work with aviation headsets, sure would love to J).
If the use case you described in more detail on the CALICO list includes the highly structured (= all students listen and respond at the same time) question/response oral
exam situation over headphones in the digital audio lab (a situation where the lab often operates at its seat capacity):
For this specific situation, I have used an audio editor to insert into the audio cue file played to the students - rather than mere gaps of silence for student responses
- some soothing sound (e.g. running water) as background noise which the students hear while responding.
This “poor man’s sound insulation” not only allows the students to focus more on their oral production without being distracted by their neighbors.
It also helps with exam integrity: Before doing that, we found responses of students sitting next to each other sometimes too similar, with a slight delay…
However, disadvantage is that this background noise also (literally) drowns out the “side tone” (= echoing back the student’s own oral production through the headphone
speakers) which can be so valuable for language learners in the digital audio lab.
Hth,
Thomas