The first thing that you want to look at when choosing a vocal processor is the sound quality. It should be top notch. The equipment should also be in a position to suit your singing style. For example, if you want a robotic sound, the vocal processor should be able to provide you with this. The same is true when looking for an alien sound. All this while giving clear and crisp output.
The vocal processor should enable the user to work with different music instruments such as guitars, microphones, pianos, harmonicas just to mention a few. It should also come with different effects such as compression, EQ, subtle reverb and pitch correction.
For the user, the equipment needs to match the sound of play. While group singers can achieve different pitches, a solo singer should be able to rely on the vocal processor to deliver the right back up such as being able to generate harmonies or loopers.
Musicians will often find the need to regularly use the vocal processor. This puts the equipment at risk of being dropped. This is why the vocal processor requires a strong and sturdy exterior to be able to withstand any eventual drop.
A good quality vocal processor needs a powerful mic preamp. It helps to improve the quality of the sound as well as making it more audible.
Pitch correction is another important feature. This also helps to improve the quality of the sound making the user sound more professional.
Look out for extra features as well such as ease of use, phantom power support, warranty or unique voicing.