Originally used by guitar players, this is a fun gadget that allows you to essentially play music on top of motives you create. In the most simple way, a player can hit the looper foot switch to record a loop, play a note or a series of notes, and hit the foot switch again to close the loop.
When first using a looper pedal, the part that takes the most practice is getting the timing right. Starting and stopping the loop at the right time is important so the loop syncs correctly, but once you are able to get that coordination lined up the musical possibilities are endless.
The loops can have extreme variance in length, from one quarter note to a whole 12 bar blues progression.
Other effects you can use depending on the type of looper pedal you have include...
- Overdubbing- recording more tracks on top of the existing loops
- Quantization- automatically syncing the loop rhythmically
- Delay- having the entrance of the loop delayed a specific amount of time
- Filtering- altering the timbre of the recorded sound
In the link here, there are a list of 5 reputable looper pedals you can purchase and a break down of specs of each pedal. Pedals can vary in price depending upon their features, with some including only the basics and others including multiple pedals and effects.
Here is an example of a horn player using a looper to perform Viva La Vida by Coldplay