Pitch Perfect: A primer on live sound pitch correction - Part 3

Originally published in Worship Musician magazine, October 2024.

“As for God, his way is perfect: The Lord’s word is flawless; he shields all who take refuge in him” (2 Samuel 22:31). Perfection is an interesting concept. In many areas of life we strive for perfection, while other domains value uniqueness and randomness and chance. Musical performance usually has a place for both approaches. We don’t want to have a worship band drummer who fluctuates from one tempo to another wildly throughout a song. It’d be preferable in most cases if the tempo was closer to a perfect metronome. It’d get boring rather quickly if the drummer didn’t have some measure of a ‘human’ touch in his or her playing, though. The same sort of distinction and balance applies when it comes to pitch correction and harmonization tools. Too much of an adherence to pitch and timing in the generated harmony parts and we risk a sort of ‘uncanny valley’ where it sounds so right that it is wrong. This last part of our series on live sound pitch correction focuses in on ways to introduce some randomness and inaccuracy in pitch and timing in order to create something that is closer to what most musical scenarios would require—stylistic accuracy rather than mathematical accuracy and precision.

Cause and Effect:

For a few vocal styles out there, a rapid correction to the scale ‘grid’ with no variance becomes an effect in its own right. Think Cher’s song Believe or the rap vocal effects used by artists like T-Pain. This sort of hard gridding effect is not very common in contemporary worship band settings, but is likely a sound that most of us have heard before. As noted, this gridding effect is caused by locking in pitch correction to a scale with little or no allowance for pitch variation—but the biggest difference (compared to more traditional pitch correction) is also setting the time for the effect to kick in as low as possible. If the signal input is a quarter step high, it would very quickly be locked down right on pitch creating an audible ‘slide’ or ‘blip’ that is not natural. These pitch correction artefacts and extreme settings are great for Cher and T-Pain and might have their place in the occasional section of a worship tune when used sparingly (and on purpose), but wouldn’t generally be the sort of effect that we’re going for in a worship setting.

As noted in Part 2 of this series last month, in most worship settings we would adjust the vocal formant as needed to soften the ‘chipmunk’ effect on the vocal tone as a first step. From there, the timing of the pitch correction and the range of allowable variance from the pitch/key should be adjusted. The key here is to think back to the Goldilocks story and aim for the ‘just right’ settings that will catch the most extreme pitch offenders and bring them back in line just at the right speed and with the least amount of strange sonic artefacts. We want to be as gentle as possible here to assist the vocals without introducing any pitch correction ‘tell’. If we are visited by congregants after the service asking about what sort of new-fangled vocal effect we used … we didn’t succeed. In this case, no news is good news. It shouldn’t be evident that we have applied any pitch correction at all.

Unique, just like everyone else:

Once we have a good grasp on the timing and variance and formant settings on a single vocal, we can start to think about harmonizer effects. These sorts of tools allow us to build up a backing choir of a few voices out of an input of a single vocal line. For this effect to work well, it is imperative that we enter the right key and scale for the song. Let’s assume for ease of discussion here that we have a song in the key of C Major. We can build a triad of voices from the input signal by creating a harmony part up a third and a fifth and an octave from our source. If our vocal input is a C note, the harmonizer set to C Major will create an E and a G and another C up an octave—a major chord. Just as we noted with the Cher and T-Pain example, we likely don’t want to have a perfect chord generated in perfect time. Using the Dual Auto Key Harmoniser within the Allen & Heath dLive system as an example, the ‘Pitch Variation’ and ‘Time Variation’ controls would be the two key settings to adjust in order to bring in the most human (imperfect) elements that we desire. Even the most professional choir of vocalists will have some amount of pitch and time variation, these two settings are the secret sauce in crafting generated vocal harmonies that work well in most worship settings.

For this effect to work well, it is imperative that we enter the right key and scale for the song

The Key To Success:

Remember in the previous section when I said “For this effect to work well, it is imperative that we enter the right key and scale for the song”? Well, how do I get the ‘right’ key and scale? Should we just ask the worship leader before the service and jot them all down per song? That is certainly one way to do it. We also have other options that could work. Again referencing A&H dLive as our example, the Quad Voice Harmoniser generates up to 4 voices of natural-sounding vocal harmony, specified in musical intervals for simplicity, which follow either the global key, a local key, or a MIDI input. Still too much work for ya? The Dual Auto Key Harmoniser adds up to 2 voices of harmony, utilizing the same core engine as the Quad-Voice Harmoniser, but with the addition of the intelligent Auto-Key mode, where a polyphonic source such as guitar or piano can be used to automatically determine the key of the performance in real-time. Auto-magical! For those of you who need to get more fancy in your harmonizing, MIDI Harmoniser creates harmonies based on an external MIDI input, from a DAW or played live, and includes a monophonic mode with a glide parameter to provide portamento between notes, plus a polyphonic mode for up to 4 voices of controllable harmony. Whether you have a MIDI input, jot down the global or local key per song and enter it in manually, or let the dLive engine calculate the ‘best’ key, you’ll need to ensure that you work closely with the worship leader and the vocal team to align musical expectations prior to the service. Once again, we don’t want any surprises here and in many cases the goal is subtlety—to not make it obvious that generated harmonization is being used at all.

Hopefully this series on pitch correction has served as a good primer of the basics. It is by no means a complete guide and there is no substitute for testing out the various settings and methods during rehearsals with live musicians. Head over to https://www.allen-heath.com/hardware/dlive-series/rackultra-fx/harmonisers/ to hear the various referenced harmony tools in action on the Allen & Heath website. Thanks for tuning in!

Originally published in Worship Musician magazine, October 2024.

By Jeff Hawley

Jeff Hawley currently heads up the marketing for Allen & Heath USA. He is pursuing a PhD in philosophy at York St. John University and serves as the Communications Officer for the British Postgraduate Philosophy Association (BPPA). Jeff has a diverse background as a musician, engineer, and trendsetting industry executive. In addition to performing and producing everything from noise music to disco and Afro-Cuban jazz to avant-garde klezmer, Jeff has designed award-winning music industry products and accessories and directed the branding and marketing functions for several top musical instrument and pro audio brands. He enjoys making strange noises, reading early Wittgenstein, and listening to George Jones—often all at once.

Connect with him at?www.dhirubhai.net/in/audiohawley