No I’m not just talking about elaborate million pound studios where there are floating floors (floor on top of another), walls within walls, that’ll limit the sound coming in and going out of the room. But having a room that has taken into consideration some of it’s over exaggeration of frequencies, reverberations, strtange dispersions of sounds etc. Good sound proofing will limit the sounds outside of the room leaking in your studio i.e. your neighbour playing his stereo out loud, cars driving pass or that aeroplane you’re convinced is coming from your snare track. So when you are mixing your track you won’t be doing things to it that aren’t actually coming from the track itself such as overuse of reverb because it sounds dry, or trying to cut certain frequencies with an EQ. Great sound proofing also means you can playback your track louder than usual, anytime of day and possibly yell and take out your frustrations on certain occasions. Below is a coefficient absorption graph of how materials can absorb different frequencies, 0 indicates perfect reflection while 1perfect absorption.
Fewer reflections can be solved using acoustic absorbers, different materials of flooring, walls, roof, and sometimes furniture with certain fabrics like tapestry, this means you will be able to hear your mix as is recorded without audio coming out of your monitors reflecting off walls that results in standing waves at certain frequencies. Bear in mind creating a mix in a overly dry room will lose the proper representation of the track resulting in emphasising or disquising other frequencies. Most of your audience aren’t going to be listening to the track in a sound proofed, isolated environment like a studio therefore, you want a balanced room that so you dont mix with false information, so that your mix will sound great in everyday environments. first find the first reflections of where sound is going to bounce off the wall to your ears first, then you place acoustic absorbers and choose the right thickness, the thicker the absorber the more you control the lower frequencies of the audio bouncing back.
Equally important, a good pair of monitors with a flat frequency response with a clear representation of your track is crucial, you don’t want to boost a load of bottom end due to your monitors poor bass response, this will result in your mix sounding over ‘boomy’ and add ’mudiness’ to the rest of the track when people are listening to it on their stereo etc. Speaker positioning is equally as important, you’ll want a equilateral triangle with the tweeters pointing at you ears, it’s no use buying a great pair of monitors if you’re just going to place them anywhere and slouch on your couch and mix. Also take advantage of the symmetry of your room, so you don’t want your station to close to one side of the wall vice versa.