I recently moved to NYC into a one bedroom apartment. I’ve been practicing all my woodwinds during the day with no complaints from our neighbors (most of which are out during the day), but have been hesitant to play the saxophone because of its volume of sound. I recently picked up a used GIK portable isolation booth. It folds up into 45”x21”x10”, opens into a 6’7” x 4’ v shaped enclosure, it works great to absorb a great deal of sound from bouncing around the room, very effective in muffling the sound if you play against an interior apartment wall or corner with the v shape behind you, to absorb the reflected sound. While the saxophone isn’t silenced, it cuts the volume and overtones substantially, without the expense and size of a whisper room.