Final product

I don't think MuseScore has any sort of built-in compressor effect. What this does is compress dynamics by articially amplifying the soft passages so they just as loud (or almost as loud) as the loud parts. So everything is all more or less the same volume. And then ythe compressor usually makes that volume the maximum that a cd can represent.

MuseScore is not an audio processing proram, so it is not the appropriate software to perfrom that sort of manipulation. But you can load the audio files created by MuseScore into Audacity or any other audio software and run a compressor effect on it yourself before burning it to CD. Most compressors give you options to control just how aggressively they work - whether they really to the equivalent of raising "pp" passages all the way to "ff", or maybe just to "mp". I say "equivalent" because it isn't just about notated dynamics. Consider, a single oboe, even playing "ff", won't be as loud as a full orchestra. So it's mot just a matter of removing dynamic markings from your score. It really has to be something done to the audio itself.

What you are referring to is the mastering process in which a multiband compressor is used to tweak the various frequency bands to give the best sound through loudspeakers.

There is no tool of this kind in the MuseScore synth.

One of the major affecting factors of this process in pop music is the compressors and limiters the radio stations use on the finished product to gain the widest coverage for their station possible. this has resulted in mastering producers (it's a specialist field of it's own) tending to master pop records to be as loud as possible, in some cases actually damaging the sound waves in the process.

The complete reverse of that situation are the signals generated by BBC Radio 3 and Classic FM (I can only speak for UK FM stations unfortunately). Their station level compressors are set to allow the quietest of signals through unaltered, and only limit the loudest signals to prevent damage to equipment.

The best multiband compressor software I have come across so far is the Sonitus multiband compressor supplied with Sonar recording and editing software, which is sadly proprietary, and therefore costs. Following my recent upgrade to a Windows 8 machine, I have, however ponied up the cost of upgrading to continue using this tool.

The following URlL takes you to the list Google throws up should you wish to read more about this.
http://tinyurl.com/cv5yvqd

HTH
Michael