At the end of Pink Floyd's Echoes the band fades and yields to a tone that seems to be constantly rising yet never runs out of headroom. A Shepard tone, or more specifically, Shepard–Risset glissando.

The effect is created by playing tones that are an octave apart together. As the higher octave reaches the top of the pitch rage it begins to fade out, and a new tone at the bottom of the range begins to fade in. The change of volume is imperceptible and leads to the constant feel of rising. Think of a barber's pole, always rising with stripes constantly being replaced from the bottom up.

It's use in Dunkirk and other Christopher Nolan films to build a feeling of tension, impending disaster, and suspense, but also as the sound for the Batpod to give an impression of constant acceleration.