Hi - I am a lay person with a practical question regarding sound. I live near a busy street and am considering having noise-reducing windows installed. The noise-reducing windows would fit beside (and in addition to) the current window to block out street noise, so in effect there would be two windows covering a single opening. My question is: if I open the two windows 4 - 6 inches to get fresh air in the summer time, will all of the noise I normally get enter the apartment through that opening, or would I still have some sound reduction compared to now because a large portion of the window would be double-covered? Not sure how sound waves move and whether a "tunnel" effect would negate the value of the noise-reducing windows. Your thoughts are greatly appreciated!