The speaker volume on my iPhone 4 (speakerphone, music, sounds etc..) stops working at least once a day. Example: If I'm listening to my voicemail and I push "speaker" I can barely hear anything through the speakers even if I raise the volume all the way up. The volume is very faint & almost inaudible (without headphones) and the volume up button does not raise the volume. The problem is remedied by doing a soft reset. Any suggestions? Thanks!