Join Alex U. Case for an in-depth discussion in this video Get in the Mix: Spreaders and thickeners, part of Foundations of Audio: Delay and Modulation.
The doubling in chorus effects we just discussed are only a starting point. Introducing multiple modulating delays with additional pitch shift, panning them out across the stereo field, we develop a class of effects we call spreaders and thickeners. These effects take an isolated track, and let us increase their apparent size in the mix. It's an essential way to help one track hold its own with others in a crowded mix. For example, you might add the spreader to a vocal track to help prevent the lead singer from being overshadowed by all the guitars and synths in a full pop mix.
This is an advanced mix move. It's a complicated combinations of processes, so plan to spend some time fine tuning the various parameters on each of the many delays that make up this effect. Once you've got it under control, you'll find this effect is an essential part of building an exciting mix that helps you sound like the pros. The transition from verse to chorus is a frequent one in music, and while the song writing and performing are the essential drivers of that emotional journey, we need to make sure that the audio engineering decisions we make are consistent with, and supportive of, the intended response from the listener.
As we did in our earlier discussions on creating doubling with medium delays, let's focus on the lead vocal track at this critical musical moment from verse one to chorus one. Spreaders and thickeners provide one of the best solutions to this production challenge, that need for an emotional lift into the chorus. The performing artists have done their part to take the energy of the verse to a higher level at the chorus. In terms of mix arrangement, we have a lead vocal floating over lush harmony vocals. A spreading effect, introduced at the chorus, is a great mixing tool for enhancing this dynamic in the song.
The signal processing elements of spreading are delay, multiple pan taps with modulation and filtering, plus a small amount of pitch shifting to further detune each modulating delay. So, you can create this affect with a delay only based doubling discussed in the earlier movie followed by a pitch shifting plugin, or you can use something like this plugin which has all the essential elements in one place. This plugin for the vocal is inserted on an aux input, labeled spreader, reached by bus from any send, in this case the lead vocal.
This effect opens with two of the four voices activated. That's a good starting point, but I want to fine tune it. I turn off the direct sound containing the unprocessed lead vocal because the original vocal track lives on its own fader. I'm mixing the effect with a vocal in the mixer, not in the plugin. This leaves the two voices. Reading left to right we see familiar parameters. Each voice has gain and pan, placing it in the mix under our careful control, and each voice has a delay time parameter with feedback.
So far, the plugin has provided us with the core functionality of a typical multi-tap delay. This is the first building block of the effect. The next three parameters focus on pitch. Changing the pitch of each delayed signal will contribute richly to the spreading of the sound left to right in our mix. The detune parameter applies a small fixed shift in pitch. How small. Listen to the effect again, and notice that while the vocal sounds different, it doesn't sound grotesquely out of tune. Pitch shifts are expressed in cents.
There are 100 cents in a dollar, and in music, there are 100 cents separating two adjacent notes on a piano. One cent is 1/100 of a half step. There are fully 1200 cents in an octave. Six cents then is a tiny fraction of a half step. 6% to be precise. So, the pitch adjustments here are very slight at six cents up for voice one of the effect, and six cents down for voice number three. That small pitch offset is further detuned in a familiar way using the modulation of the delay.
We're offered the standard parameters of depth and rate to do this. Modulating the delay as we've discussed many times in this course, causes pitch shift. So the spreading effect is a delay, plus pitch shift process. And, while two voices of this patch achieve a lot, we should listen to the effect when it's built of four voices. Here's the chorus of the song. I'll start with two voices on, and turn on the other two halfway through. This process spreads the vocal out left to right, and seems to thicken the texture and harmonic content of the track.
I've overdone things here a little a bit to make the effect easier to hear, but also to suggest that, for an attention getting special effect, this can be a creative avenue to explore. But for this mix, I want to keep a more natural sounding vocal. So, let's adjust these parameters to tuck the effect into the mix to place it in a more supportive role. First, I'll introduce some delay modulation to each voice, very much with a traditional chorus in mind. Listen as the effect grows richer. I want the effect to be wide, and harmonically thick and dense, but I need to make sure it only adds to the lead vocal without taking over the mix.
So, some adjustments to the level and panning bring the effect in line. And then, I set the overall level of the effect. It's too loud in the mix now, so I'll pull it down, first too far, and then ride it back up and pull it back down, all as needed until I feel like the vocal gets the necessary added strength and interest that I want it to have in this chorus. Now we need more context for this effect. Let's listen to the verse to reorient ourselves to the sound of the lead vocal without the spreader, followed by the chorus of the tune, to hear and feel the impact of this effect.
The goal here is to help fabricate that pop music, larger than life, layered vocal sound in the chorus. This effect does it quite nicely. I'm going to make one important change though. Having the effect kick in at the chorus is great, but I'm a sucker for a bit of anticipation into that chorus. Melodically and emotionally, our singer starts to rise up on the line leading into the chorus offering a sort of emotional pick up into the chorus. So, I introduce the spreader effect ahead of the chorus, on that phrase right before, when she sings we gotta know exactly why we came here.
Let's listen from the very top of the tune, acclimate ourselves to how the song unfolds, and make sure we have appropriately contributed to that. This build into the chorus, based on the musical addition of the spreading effect, serves the music well.
- Adjusting the delay time, level, and feedback parameters
- Utilizing a low-pass filter and polarity reverse
- Setting up an effects loop
- Setting the delay time by tempo or by ear
- Understanding the distinct uses of short, medium, and long delays
- Adjusting modulation rate, depth, and shape
- Adding double tracking and spreader effects
- Manipulating tone with constructive or destructive interference
- Creating a comb filter and flange effect