There's a stickied thread on the pro-audio forum that deals with this topic:
http://talk.philmusic.com/board/index.php/topic,31588.0.htmlMadaming math, madami ring posts intended for building recording studios, so just breeze through that. Pay special attention to posts by mikep, Direk, alien_inside, etc.
IN A NUTSHELL:
SoundProofing (Sound Isolation) is different from Acoustic Treatment.
Soundproofing basically means NO SOUND COMING OUT. For this you need MASS to stop soundwaves, especially the mids and the lows that go through walls. The heavier the material the better. EGG TRAYS or EGGCRATE FOAM WILL NOT SOUNDPROOF YOUR ROOM. THEY'RE TOO LIGHT. THEY WON'T STOP ANYTHING.
A thick cement wall (6" concrete hollowblocks) will do a better job at soundproofing. If on the other hand you have wooden walls (like I used to have in my parents' house), then you're [gooey brown stuff] out of luck.
As for Sound Treatment, The Eggtray / Eggcrate foam approach is supposed to give you a DIFFUSIVE surface, para walang echoes. But in my experience it doesn't really do much in terms of guitar sound. DRAPES / THICK CURTAINS are a better solution. For parallel walls you only need to cover one wall. Better if floor to ceiling. Try hanging it at least 3-4 inches away from the wall. If you can't find thick curtains, two thin layers will do the trick.
The least you can do when you're practicing is to close the door.
invest in a small airconditioner para naman komportable ka sa loob.
