Most raw recordings require a certain amount of cleanup before mixing. Removing static, unwanted ambient sounds such as lyric sheets being turned, and dealing with clipping and distortion, are all part of the cleanup process. Most digital audio workstation applications, such as Logic and Cubase, have tools for these purposes. The next step is to properly equalize the vocals, usually using a multi-band graphic equalizer. Mid-range frequencies are somewhat emphasized, while frequencies below 50 hertz are removed, or “cut,” to eliminate any low-frequency noise that may muddy the overall mix. Equalization is the engineer’s primary tool for shaping tone and lifting particular parts above the rest.
Layering is often used on vocals and solo instruments, in conjunction with panning, to give them a greater sense of space within the overall stereo field. This is particularly appropriate in hip-hop because hip-hop vocals tend to heavily dominate the mix. The audio engineer creates two or more identical copies of the vocal, each with its own track. The original vocal track is left center-panned, while the copies are panned left and right. This procedure “widens” the vocals, helping them to properly dominate.
Correctly setting the volume of the vocal track, relative to the other tracks in a mix, is another important aspect of mixing hip-hop vocals. While many engineers make this their first step, others layer and pan the vocals first, then send all vocal layers to a dedicated mix bus to apply compression before adjusting the relative volume. Compression directly impacts the perceived volume of a track by increasing the volume of the quietest parts and decreasing the volume of the loudest parts. If the relative volume is set before applying compression, the relative volume has to be adjusted again to compensate for the effects of the compressor.
Almost any creative effect processor, including delay, analog emulation and auto-tuning, may be used on hip-hop vocals to alter or enhance them to taste. An important exception is reverb which, unlike other genres, should generally be avoided when working with hip-hop vocals. Hip-hop vocals tend to be fast-moving and highly rhythmic. Applying reverb “blurs” the articulation and rhythm of the vocals, making them more difficult to understand. Furthermore, reverb serves to blend the vocals into the stereo field, undermining their “prominent and aggressive” character.