Lesson 65

Mixing Rap Vocals to a Backing Track

So this is something that has come up many times with clients coming to the studio and wanting to record their rap vocals to a backing track. We have an entire lesson about recording rap vocals, in lesson 3.6.1, so in this lesson we’re going to focus on the mixing component. 

Mixing rap vocals to a backing track is something that really annoys me. I don’t like doing it, because it never sounds as good as it would if you had the separate tracks. Even if I could just separate it into 4 tracks, for kick, snare, bass, and then everything else can be together, I could get it sounding way better. But anyways, this lesson is how to deal with the inevitable single track and adding all the vocal layers to it. You see, there’s a few problems here. The clients that want to bring in a backing track are usually amateurs. They will choose the backing track that sounds best to them. Usually, it will already be mastered, with EQ, compression, and reverb. So we add the vocals on top, and then what? Master again? Well you can’t really undo what’s already been done, and the backing track has already been summed into one cohesive song, and now we’re adding several layers of vocals and summing again, and mastering again... it sounds like a disaster, but there’s ways to minimize the negative aspects, and bring out the positive attributes.

First off, as part of the mastering process of a song, there’s this effect called glue. It’s like, all the individual parts just join together like they belong. This is because we have all the parts going through the same processing and it just gives them a similar character. The single most influential part of this glue effect is the mastering compressor. It swings the master track volume up and down subtly on a pleasant and musical way. When it’s done right, we don’t even notice it. The problem is, the backing track is already compressed, and if we add the vocals then compress the whole song, the backing track will be over compressed. So what I do to counteract this is add an expander to the backing track. An expander is the opposite of a compressor. Whereas a compresso will take the loud parts and make them quieter, and take the quiet parts and make them louder, an expander makes the loud parts louder, and the quiet parts quieter. If done properly, you can basically undo the compression on the backing track. 

Next what I do is EQ out some lower mid range. If you recall from lesson 4.3.1.2 advanced use of EQ, from 100- 400 hz is the mud range. Since the backing track track was mixed to have the optimal volume in that range without vocals, when you add the vocals in it will get muddy in that range. So I just put a nice little EQ dip from 100-400 hz, centerred around 250 hz. 

I also sometimes like to boost the bass a little bit, like this. Make sure the EQ is before the expander. 

So that’s what I do to the backing track.

Next is vocals. Since the backing track will already have reverb, we’ll want to add reverb to all the vocal parts to try and match the backing track, but don’t add too much, because we will be adding reverb again in the mastering phase. And of course, the standard mixing techniques for vocals apply. There’s a whole lesson on mixing vocals, so you can check it out, lesson 4.3.4, mixing vocals.

And that’s pretty much it. Next is mastering, and your standard mastering techniques will be used. I go over mastering in lesson 4.13. The only thing I do a little different in mastering is apply a bit less reverb, because the backing track already has reverb, and we don’t want it to be too wet. I also put a low cut filter on the mastering reverb around 150 hz, so I’m not adding any reverb to the lower frequencies, that way the bass remains punchy.