Is there any rule of thumb for how loud/quiet the dynamics should be played?
Like, when I see "pp" I know to play it softer than "mf" or "f", for example, but I have no way of knowing if I'm playing it soft enough, or if I'm making it different enough to when I play"p".
Is there any tips or practices that I can do to help with this, or do I simply have to listen to the piece that I'm trying to play, and copy it?
I use this mental guideline (not as in decibels but more in the sense of 'effect'):
pp: whispering, as silent as you can play
p: having an intimate conversation with someone standing next to you
mp: having a normal conversation with someone standing next to you
mf: having a conversation with a group of people in a meeting, everybody needs to understand you, even in the back
f: shouting
ff: roaaaaaaarrr, as load as you can play
When you listen to a recording of the piece you want to play, listen to several different ones. You'll notice that it's not the same dynamics for each player.
As a rough guide, pp ( or ppp) is just about as quiet as you can play, to ff (or fff) just about as loud as you can play. Problem is, it depends a lot on the instrument, the room it's in, you as a player, and probably other factors too. And it'll depend on where you yourself put the mid point, from which all the markings are relative.
There's no exact middle point, either. It goes from mp to mf, as there can't be an 'm'. So, it's all rather relative. Obviously f is louder than mf, and pp is quieter than p, but there are no decibel readings for any of the dynamics.
In fact, they're there as a guide rather than etched in stone, and while some pieces sound great when the dynamics are adhered to exactly (although even that is subjective), others can benefit from your own interpretation, or even a re-jigging of it all. Most players will let the music do the speaking, and rise or fall accordingly. We're back to ears again, I'm afraid!
It varies with the piece, the instrument, the size and acoustics of the room... Just make sure you can fit all the required dynamics into the overall scale you choose.
Generally speaking, Pianissimo would be as soft as possible, Piano would just be soft, Mezzo-Piano would be semi(or half) soft, Mezzo Forte would be semi(or half) hard, Forte would be loud (hard) and Fortissimo would be as loud or hard as possible.
With all these things said you are allowed a fair amount of artistic license in these matters, as long as Piano is softer than Mezzo-Piano and Fortissimo are louder than Forte, you should be OK.
These matters are not an exact science, as long as your music portrays the correct character the finer details on how loud is loud is not important.
From my personal experience, it is kind of relative. It helps to look at the overall dynamic range of the piece you're playing and set the loudest and softest you want to go before you start playing. But really, as long as there is a noticeable difference between pp, p, mp, mf, f, and ff, and you can switch between them and make sure the change is noticeable to your audience, then you've done it right. If your audience (or you when you're listening to yourself) can't tell that you just switched between mp and mf, then maybe your overall range is too small, and you need to make your louds louder and your softs softer, to ensure a good dynamic variety.
