Call voice can not be done

Dear all,

I have installed Openfire (3.6.3) & Spark (2.5.8) for communication in the office.

Has been running well, but there is a problem in communication via voice.

Where when we want to make a connection to a “computer to computer” (call voice), who received a voice not heard clearly,

only the sound of noise that is not clearly heard.

I have reviewed in connection handset each PC (line-in & mic), there is no problem at all.

There may be a solution that can give ?

Best Regard’s

(AVERRO)