is my monitor defect or i have to set something up?

DuckLord1

i bought this monitor named acer 23 inch r1 series, i plugged my speaker on the audio in but somehow the sounds kept playing on the internal speakers of the monitor.Later on i tried plugging my speakers on my brother's monitor and it works.I also tried changing its defaults but it also doesnt work, i even tried plugging a earphones and im not recieving any sounds or somewhat.

billsey

There are several different models in the R1 line, which one is yours?