We could surely use a stronger vibra, no doubt about it. Maybe some software update will fix that. I doubt N9's vibra is so weak. It's prolly just set to be so.

I had a look at the Alsamixer, but mine was already at 100 ! Done through the normal settings.

are you sure? and what have you done to the setting?

Settings >>> Sound & Vibration >>> System sounds, I set this to level 3 so i assume that the max level for system sounds also means that the ringtone is at max. A ringtone being a 'special' system sound perhaps ?

There are plenty of ringtones that I find too loud, even though my hearing is far from perfect.

I have noticed my N9 have different volume of changed ~2 weeks ago - it was somehow low, but currently it is just perfect, and even I have to keep not to the max to be in tune with my preferences.
I think I got the moment when this change occurred - the phone was close to me, running out of battery juice, in power saver mode, then a sms, followed be email came but the notification sounds the phone made were somehow awkward and distorted, lasted longer then they should. After that when I charged the phone overnight the first call received next day - the sound was very loud and I was surprised. So was the next and so on. From that day I had to move the ringing volume down to notches from max.
I know this sounds a little crazy, but I think - can some changes occur to pulseaudio? O ALSA?
I have experienced such changes 1-2 times before, after phone reboot I have loud and clear sound, until the next reboot pushes it back to quiet again.
Anybody with similar observations?

I too had this problem till I went to the =>settings => Sounds and Vibration then using the volume buttons on the side of the case I found that this adjusted the ringer/message volume and increased the vibration intensity.

Took me bloody ages to work this out

^I will add this to the guide.

Can alsamixer be used to increase the volume of the earpiece too?

I find it to be pretty low even at the indicated full volume.

I'd advice not to use this Alsamixer, one developer mentioned a risk of changing default settings, sound also gets distorted when activated. Not a reliable solution at all.

That doesn't work....

I got to the sounds and vibrations and pushing the volume buttons changed the profile from silent to beep to ringer, they didn't change the vibration level.