Let's give more time to how DJ's create their set's sound.
Duane opened his show with a set which included "My Country 'Tis Of Thee" by cross-dressing singer Sylvester, then the soul of Sandra Phillips, Monik, and Marc Eric. Notice how the sequence begins at a medium level of intensity, then is brought to quiet calm by Eric's mid-1960's beach sound.
Here's another way a DJ can smoothly change the feel of a set, mid-way: On More Than A Few Exciting Moments, Frank O'Toole played a mono mix of "Savoy Truffle" by the Beatles, then audio from Alfred Hitchcock's The Birds, then modern electronic music by David Holmes. Without the spoken Birds audio, the shift from the Beatles organic sound to the mechinized sound of Holmes would be jarring, but this audio opens a gap into which Frank can effectively insert any texture he wants.
On Underwater Theme Park, Meghan used three songs with different sounds but the same name, "Palestine." Hear how the middle eastern tinge of Gokh-Bi-System transitions into the psychedelia of Gong, then the punk guitar roar of Autonumadic. The connection might not be instantly apparent to the ear, but listen with the shared title in mind, and the thread shines more brightly.
Listen to Stan's show, on in the middle of the night, and his selections are often geared to work on the half-awake subconscious. Here, he plays the quiet guitar sound of Just Others, followed by the even softer "Easy On Your Eyes," 1970's-like soft-pop given modern jazzy revision by the Aluminum Group. You can listen actively and dissect each detail, or let the music seep in with your mind on sleepy auto pilot. The tracks could work together any time of day, but the early morning still and dark lend a dreamy nuance to Stan's work.
Nat Roe's show is even more custom fit for it's 3-6am time slot. He spends this time mixing any music he pleases, such as this set of the Top 100 Of 1987 or his Smooth Jazz For Special Night Moods. His raw material is not the point. The shimmering layers here are the stuff of your most fluid dreams, a reality that is impossible in conventional song structure, or waking hours. Nat's work is as shape-shifting as the dark you sleep in, as surreal as the mind leaving the constraints of time and space.