Hi Sergio!
In my opinion, processing for different bitrates doesn’t really differ much, except that one needs to maintain more short-term dynamics for lower bitrates to make sure the codec has somewhere to hide coding artifacts.
For Jazz and Classical Music, I recommend Reference Settings. It’s a great all-round preset, never does anything unpleasant, and yet controls levels and sweetens the audio enough to sound exciting. It also stands up to scrutiny, even in large hi-fi setups.
Oldies is little trickier, because of the varying recording quality. You might want to try the Twente preset — it’s punchy, big-sounding, and designed to handle Oldies — it avoids fast gain-rushing to keep background noise down.
For Rock, there’s several different presets that come to mind. I’d probably go with Plutonium, or Twente with a little more range and speed.
Please make sure to use the very latest version — there’s a much newer version on the forum which has yet to be released on the main download page. The thread is up at the very top.
Best regards,
///Leif