You might try isolating your sub from the floor. For $60 bucks, an Auralex subwoofer isolation platform can work extremely well...we use it under our Velodyne DD18 and it is great. Much better bass, and no complaints from the neighbors!
Start there...and you [might] try the same with your speakers using Stillpoints or something...but start with the sub.
Start there...and you [might] try the same with your speakers using Stillpoints or something...but start with the sub.