you no longer must suffer the ups and downs, steep falls and steep increases in volume, normally found in all collection that has more than 40 or 50 mp3s. much more, if the person has thousands of mp3s that has painstakingly managed to collect but have (for each come from a different encoder and have been encoded with very different setings) with uneven volume levels.

Make this proper case
You no longer must suffer the ups and downs, steep falls and steep increases in volume, normally found in all collection that has more than 40 or 50 mp3s. Much more, if the person has thousands of mp3s that has painstakingly managed to collect but have (for each come from a different encoder and have been encoded with very different setings) with uneven volume levels.