Asterisk mp3 file problems


I am using asterisk-1.4.2.

I want to play mp3 files, When I play the mp3 files using MP3Player application in the dialplan I get a good quality sound; however if I use Background; the sound volume is very low.

Why is this problem arising? On some forum, I found that I should make some changes in apps/app_mp3.c file, by locating lines where mpg123 is being called; basically changing 8192 to something louder like 32768. I did that and recompiled asterisk, but my problem has still not been resolved.

Is it something to do with module. Should I reinstall it or something? But, why is it working allrite with MP3Player command and giving trouble with Background command only?

Any help would be appreciated.Thanks.