iPhone 6 Plus volume

Hi All,

I have just come back to Apple from Android and bought myself a nice big iPhone 6 Plus however, the speaker/main volume does not seem anywhere near as loud as my previous iPhone 5 or my partners iPhone 5S. I have checked all the obvious things in settings and rebooting the phone but the volume still seems low. Could it be a hardware issue or is it just that the 6 Plus system volume is lower??