Logic Pro from A to Z – Q is for (Smart) Quantize
In the following article from the “Logic Pro from A to Z” series, Eli Krantzberg takes a look at the Smart Quantize feature in Logic Pro X, and how it got a lot smarter since the big 10.1 update.
Quantizing – The Early Days
Quantizing is a feature that, probably more than any other, has influenced the aesthetics of modern music production. Logic has always had it, but it has just gotten a lot smarter since the Logic Pro X 10.1 update. In the early days of sequencing, sixteen or steps of notes could be programmed and played back. There was no quantizing necessary. A note could fall on one of the available steps, and that was it. Smarter drum machines eventually came along, and notes could be sequenced with increasing degrees of resolution between each of the steps. Quantizing was born.
Quantizing quickly became the norm for programmed beats and programmed music. But then something happened. With the advent and development of MIDI, the degree of resolution between beats subdivisions grew exponentially, thus allowing the timing nuances of recorded parts to almost perfectly preserve the feel with which they were played. With the increased resolution, it became more necessary than ever to clean up, or “quantize”, parts that were played in sloppily. In it’s simplest incarnation, quantizing simply involved moving sequenced note events so that they fell exactly on specific beats or beat subdivisions instead of one of steps of resolution that were available between them. But what about all those steps of resolution between the beats? Surely they could be harnessed and manipulated for something other than “just” capturing the timing nuances of live performances.
Logic Pro’s MIDI resolution has always been 960 ticks between each pulse, or beat. Quantizing had to get smarter. In addition to evenly rounding off the placement of each note – or event – to specific musical subdivisions, the notion of quantizing by percentage was introduced. The idea was to take the timing of the performance as a starting point, and shift the notes a portion of the way closer to the beat subdivision grid without forcing them all the way. In this way, some degree of the player’s performance could be retained, while also pushing (or pulling) it closer to the beat subdivisions, utilizing the discreet number of steps, or “ticks” between each subdivision in the process. The notion of adding swing to quantizing came into being as well, allowing specific notes within the grid of subdivisions to be pushed later so they were not spaced evenly, thus creating the illusion of a swing feel.
Q-Range, Logic Pro’s hidden secret weapon, takes the ability to utilize the resolution of the timing grid a step further. When set to negative values, notes falling outside of the set tolerance are quantized, while the notes inside it are left unaltered. In this way, the feel of a performance is maintained, except for those notes that fall noticeably far from the subdivision grid being used. When set to positive values, it does the opposite. It corrects the notes that are close but not exactly on the subdivisions, and leaves the ones farther away unaltered.
Quite frankly, this whole system worked very well for a long time. Until the notion of using user defined timing grids instead of preset musical subdivisions was introduced. This allowed for the quantization not only of note events, but also note velocity and note length. Even more nuanced aspects of the human performance could be controlled.
Then computers and computer software got smarter. In addition to solely capturing MIDI performances, it became possible to capture actual audio recordings. The two realms lived relatively separately for a while. But eventually the notion of quantizing was developed for audio. Soon audio recordings could be analyzed for peaks, or transients. These peaks were used as timing references for the performance. The audio could then be either stretched or sliced, in order to shift those transients either to, or closer to, the musical subdivision grid. Logic Pro’s Flex Time introduced the ability to either automatically, or manually, shift specific hit points in relation to the grid, using just about all the timing manipulation available for MIDI events.
Quietly working in the background, the developers of Logic Pro have now developed a new level of “smart” quantization, aptly named Smart Quantize. Smart Quantize possesses algorithms necessary to make sophisticated and complex determinations based on the human performances it is put to work on.
Rather than simply moving note events based on preset Strength, Range or Swing parameters, it takes other factors into account in determining where notes will be placed on the grid. It factors in not only the position of the notes in relation to the target beat division value, but also the velocity of notes, the end of the notes, and how closely they are played together. It calculates a kind of “centre of gravity” when there are multiple notes played in close proximity to each other, and uses this centre of gravity to shift the group of notes closer to the grid while still maintaining the significant relationships in distance they have to each other. It thereby preserves the integrity of the timing of your performance, while ensuring that notes intended to fall on beat divisions end up near the corresponding grid increments.
Additionally, all MIDI events keep their original order. So when you play a static chord, they don’t all get quantized to 1 1 1 1. The individual notes will be offset from each other by a few ticks.This is a subtle nuance, but really helps preserve the manner in which they were played in.
Notice the dot next to each number, indicating Smart Quantize is enabled:
Below, the same performance with quantize set to “off”:
What is particularly impressive is how Smart Quantize determines which notes to exclude, when playing notes deliberately far from the grid. It seems to me that what is at play here is an algorithm that simultaneously factors in the relation of the notes to the desired grid and to each other. It then contiually recalculates and adjusts the Q range parameter in the background, resulting in invisible constantly shifting range values that take into account both the desired gird, and the intended relationship of the notes to each other.
When Smart Quantize is enabled, a new parameter, called Q-AntiFlam, appears in the extended region parameters. This parameter seems to be undocumented. It defaults to a value of 0%, suggesting that when it is off, the Smart Quantize algorithm is working optimally based on its own calculations. Adjusting it’s value seems to cause the Smart Quantize algorithm to recalculate based on…. I don’t know what exactly.
When the Q-AntiFlam parameter is set to 100%, the notes become fully quantized in the Classic Quantize tradition. When set in the neighbourhood of 50%, some of the notes begin to lose their dots, suggesting that perhaps quantizing is not being applied. Yet the position of the undotted notes changes when quantizing is set to off, suggesting that in fact there is still some “centre of gravity” weighting at play even when no dots appear.
Logic Pro X Smart Quantize – a Game Changer
Quite frankly, unravelling the complexity surrounding Smart Quantize seems daunting. And in reality, unnecessary. It does its magic in the background and really is pretty Smart; at least when interpreting my technically challenged keyboard performances! It is, in my very humble opinion, perhaps the single biggest “game changer” feature added to the Logic Pro X workflow that will certainly change the way I approach using quantization. At the moment (it’s still early days with it) I can’t imagine a time I would want to work without it on, unless doing strictly programmed dance music. Which brings us back to the top of this article. Smart Quantize will undoubtedly influence the aesthetics of my personal music production, and likely many others, now that it is here. In the spirit and tradition of Steve Jobs, and the old Emagic days, the Logic Pro developers have delivered a feature I didn’t know I needed, and now, cannot imagine living without!