the Strymon DIG (dual delay) has a setting called the "golden ratio", which is something that appears in nature everywhere and is used in painting and architecture also. It creates an interesting effect where the 2 delays dont bump into each other and sounds very spacious and ambient. You can create it using any 2 delays though.. set 1 delay to the BPM of the song, and times that by 1.618 for the second delay. keep the mix less than 50%. play around with it. lot of fun.