Audacity Forum

Technically speaking... Dynamic compression and limiting are distortion... They change (distort) the wave shape and dynamics. The trick is to get the desired effect without it sounding like distortion.

Mastering (and re-mastering) is an art. It requires trial-and-error and careful listening. It starts with listening to determine what's wrong, or what can be improved. Loudness is only one factor. You may only want to boost the loudness, but as you've discovered doing so non-linearly (with compression or limiting) can affect other aspects of the sound.

Mastering also requires good monitors and a "good room". And of course it helps if you have a "good ear", skill, and experience. You are unlikely to get the same results as a pro mastering engineer, and you are unlikely to have the same tools (hardware or software) as a pro mastering engineer. (You may not want the same results as a pro... Many listeners don't like modern "constantly-loud" Loudness War recordings with no dynamics.)



Here are some mastering links I've collected:

Moulton Labs - What's This Mastering Business Anyway?
Moulton Labs - Tips n' Tricks For Mastering
Izotope - Ozone Mastering Guide (This is written for Ozone but most of it can apply no matter what tools you are using.)
REAPER Forum - Discussion of a particular mastering job (The mastering discussion starts at post #8).
Mastered For iTunes

Yeah, more than Loudness im searching for Quality to hear everything ( From Voice to Instruments ) as they Loud and Clear, because if its so Loud can cause Damages and distortions unwanted,so the Normal Loudness but there are music that needs to be full Remastered and other song that the waveform needs to reach the top as if were new or other songs that already reach the top on their waveform.