Some commonly used vocal effects are the Creepy Whisper effect, the Megaphone effect and Advanced Artificial Double Tracking. Voice Delay effects are also popular, and generally feature a delay of between 25 and 100 milliseconds.
The Megaphone effect attempts to replicate the sound of a voice being sung through a megaphone speaker. Most megaphones are of low speaker quality and create heavy distortion; therefore, audio can be intentionally distorted in a certain way to recreate the sound patterns a megaphone creates.
Advanced Artificial Double tracking is another voice effect that is popular in the modern audio industry. This is the process of doubling a voice by adding in a delayed, artificially created voice. The standard delay for this effect is approximately 20 to 30 milliseconds, and the voice is created by slightly tweaking the original vocal recording. This allows the recording process to be shortened as the singer does not have to record a second vocal track.
One voice effect that sound engineers use widely is compression. Compression tools restrict the dynamic range of sound, causing the audio to sound more "even." Many vocal effects can be achieved using different types of compressors. Aggressive Compression is a widely used effect in several rap and death metal genres.