Do you still have sound coming into your home studio you know like a TV from another room or maybe you can hear water running from the dishwasher or anything else. There are three areas that get overlooked when building a room for sound work first is electrical wall plates and switch plates. Like most rooms there are multiple plates and each is capable of letting in sound or noises. Since the boxes are already in the wall (and if you can't take them out) you will need to caulk around the opening between the wall and the box hopefully it's not to wide. If it is you can use acoustical putty and fill in the edge around the box and it is fire rated also you can use the spray foam that you use around outer doors and windows. Then find some thin foam cut it to fit between the plate and wall cut out your plugs or your switches and screw holes as close as you can then screw the plate back on. Next doors and windows now here we want to create a small vacuum when you shut the door or window so for the door we need a threshold with a rubber seal on the top so when you shut it compresses the rubber seal. On the door itself down at the bottom screw in a door strip with the rubber edge on it and make the edge barely touch the floor you don't want to see any light coming through under the door. Now around the door in the door stop you should have some kind of seal that will not stick to the door itself I recommend Q-Lon or Zero International they both make kits that work well for this situation. With windows there are usually the slider type and depending on how old they are depends on the glazing I recommend two or three pains make sure the caulking around both sides of the window is not old and worn from weatherization if it is remove it and re caulk. The third place is your H VAC system and depending on the money and resources you have depends on your fix. My studio is in the basement of our house it stays about 60 degrees which is great in the hot summer months everything is turned off so no noise. But in the winter months the heating system is turned on and (I always seem to record more in the winter) so what I do is I use a small space heater in the room your recording in. And I will turn the main system off while the session is going on then I turn it back on when I'm done. Turn the small heater off in between tracks. Unless you have cash to burn you could install a mini-split system where the main unit is outside and the air movement part is inside the room including wall /ceiling ducts and they are very quite. For more on recording tips go to http://www.musicanddjinstructionalmedia.com/homerecording.html
