Recording Calls with *1

Hello , This is my first message in this forum , i would like to thank those who have created this wonderfull application , well i have installed everything just fine and have created trunks and outbounds for betamax then i have created the extensions and untill now everythings run just good , but when i tried to record a call pressing *1 it save a file and recorded but in strange way , first you hear very clear the second person talking to me and i cant hear my own voice after seconds i can hear my voice and his voice desappear what could be the problem please.??