Sibilance is the ‘ssss’ sound which becomes prominent when the speaker has a voice of a higher pitch or when the room in which you’re doing the recording has an echo. This can be a problem in on-camera interview situations. With a large mic, like a shotgun or cariod mic, we change the recording position to minimize sibilance. When using a lav mic, reducing sibilance is a bit tricky.
A lavalier microphone, more commonly referred to as a lav, lapel or clip mic, usually attaches to clothes to allow us to capture sound hands-free. As they’re relatively close to the mouth of the person being recorded sometimes sibilance can sometimes be a problem.
If you’re recording in a studio environment or somewhere where the sound is dampened then something turning the mic upside down is one way to reduce sibilance.
This technique also has the added bonus of reducing breathiness and popping in speech. The lav mic would has to be an omnidirectional type of microphone for this to work, which most are. This technique will not work in a room with an echo either as it will just serve to amplify the issue.
Placement is something to think about too. Which side is the clip on? Be aware of ties or collars, basically anything that might rub against the mic; something perhaps more likely to happen when the mic is upside down.
In summary
Turning an omnidirectional lapel mic upside down is a useful trick in a studio environment or ‘dead’ space for reducing popping and sibilance. If you’re ‘in the field’ or somewhere where you’ve got an echo or lots of external noise then you’re better off using a cardioid and having it the right way up, taking into consideration mic placement and proximity to the speaker’s mouth.