Alongside processors, an understanding of effects is equally important. This chapter discusses the most commonly employed effects within dance music to introduce the foundations of production. While compression could be considered an essential processor, reverberation could be regarded as the most important effect. Artificial reverberation is available in two formats, convolution and synthetic. The ratio determines the relationship between direct sound and amount of reverberation. After a sound occurs, the time separation between the direct sound and the first reflections reaching the ears is known as the pre-delay. Alongside emulating this response, pre-delay is used to prevent the reverberation field from smothering the transient of an instrument. Decay determines the period the reverberation will take to decay. In large buildings, the reflections take longer to decay into silence than they do in smaller rooms. Alongside reverberation, a digital delay is one of the most critical and influential effects in the production of electronic dance music.