Two effects pedals for the electric bass guitar that more or less manipulate time are delay and reverb.

The delay or echo effect is basically achieved by recording an input signal, storing it, and then replaying it over and over again.

The controls on a delay pedal allow you to adjust the intervals of the echo, so you could choose to have short or long delays. Delay/echo is another one of those effects that are more often used by guitarists than bassists.

The delay effect

The reverb effect

The reverb effect is basically a simulation of the sound you get in a hollow enclosure like a cathedral or concert hall. This sound is created acoustically when numerous echoes are built up and then gradually fade away. Now when it comes to effects pedals, the reverb effect is created digitally by signal processing algorithms.

Some of these algorithms themselves create a series of artificial echoes by using multiple feedback delay circuits. Reverb in general is a very subtle effect, especially when it’s used with the bass guitar.

It could be used in conjunction with let’s say distortion and give your bass a much richer sound.