I've noticed that both my speaker and in-call volumes have reduced drastically since I updated my (rooted) Galaxy Note GT-N7000 to the Android 4.2-based AOSPA ROM. On investigating further, it appears that most (if not all) 4.2 ROMs suffer from this problem.
The most common solution suggested is to use some sort of equalizer app such as Volume+, but these apps don't appear to work for me(and from I've read that they are incompatible with JB anyway).
Is anyone aware of a way to fix this, or will I need to downgrade to a 4.1 ROM? I live in a rather noisy city, and it's getting annoying to not be able to hear what people are saying.