Before we learn the difference ways to pronounce ED, we must first know what voiced and voiceless consonants are:
Voiced Consonants vs. Voiceless Consonants
A voiced consonant (or sound) means that it uses the vocal cords and they produce a vibration or humming sound in the throat when they are said. Put your finger on your throat and then pronounce the letter L. You will notice a slight vibration in your neck / throat. That is because it is a voiced sound.
A voiceless sound (sometimes called an unvoiced sound) is when there is no vibration in your throat and the sound comes from the mouth area. Pronounce the letter P. You will notice how it comes from your mouth (in fact near your lips at the front of your mouth). The P sound doesn't come from your throat.
Try this with the other letters and you will "feel" the difference between a voiced and a voiceless consonant (or sound).