Etymotic Research er-22 Guida Utente

• obtaining a good seal in the ear canal
• positioning the microphone close to the mouth

Select an eartip that allows the earphone to seal the ear canal so
that it stays in position and the boom does not rotate downward
during use. Position the earphone securely in the ear. Moisten
the eartip if necessary to ease insertion.

The microphone is highly directional. It will pick up your voice
within a narrow range and reject background noise that comes
from outside that range. To stay in this range, bend the boom so
that the microphone is within 1/2 inch of your mouth. Excessive
jaw movement can cause the eartip to work out of the ear if it is
not well sealed. Occasionally check the 
fit of the eartip to ensure that the boom
remains in place and the microphone 
does not move away from your mouth;
otherwise the microphone will reject 
your voice and you will be difficult to hear.