What is the best way and material to use if I want to sound insulate my the ceiling in a basement office. I have a suspended (drop) ceiling in the office areas. I want to keep the sound from the office from going up into the 1st floor areas.
You can add 4" or 6" fiberglass batt insulation over the lay-in ceiling. It comes in 24" wide rolls that you will have to cut to 48" lengths to be manageable. They can also be ordered in 24" x 48" size, but for one office it isn't worth the trouble. Order unfaced (no paper) batts or leave the unfaced side up. Do not lay batts over light fixtures as this poses a fire hazard. Do not lay batts over return air grilles as this may adversly affect your A/C system. Lastly, you can add a "white noise" machine that provides background noise to mask your conversations.