/ Examples / Control / Session Grid

Wherein we demonstrate the raw power of Session Grids.

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Theory of Operation

A Session Grid is be used to schedule or trigger downstream notestreams like NoteGrid. It can play a role analogous to the Timeline or Session View in most DAWs. The Grid Editor is used to produce the session grid files that drive the Session Grid node.

This example offers you two projects for the price of one. The first, Tempo Session introduces the basic capabilities of a Session Grid. The second The Challenge is a sort of Rube Goldberg Machine intended to confuse, amaze, amuse. Your challenge is to understand its functional components.

Tempo Session

Here's the graph, tempoSession.chg. The top row is a run-of-the-mill notestream-based synthesis subgraph. Below that, the SessionGrid node is delivering messages to control the TimeKeeper in a fashion similar to that presented in this example.

The SessionGrid node's File parameter is set to tempoSession.fgrd shown below. This file has a single cell with a duration of 21 measures. Within that cell you can see a reddish graph of the BPMPct. In the right sidepanel we see that BPMPct is both visiable and drawable and this means that you can use your mouse to "draw" the tempo changes for this session. Having drawn this nice picture, you might wonder what range of tempos does this graph represent? This question is answered by inspecting the Remapper node where you'll find that we remap the graph range [0, 1] onto real BPM values [100, 200].

When you perform this graph you can follow-along in the Grid Editor and watch the tempo evolve. Easy as pi.

Extra credit:

• As described elsewhere the SessionGrid cells are "decoupled" from the graph timing. They do share the same timekeeping but here, you'll note that the Scale completes before the end of the BPM cell. It's simple to bring them into conformance by editing the cell duration in the Grid Editor.
• If you find that need more or less event-resolution in a cell you can right-click on it and request Resample. Note that this only applies to the active subevent channel.
• You can add comments to your Session Grid. Just activate (or create) a Comments Layer and create a comment cell. When selected, the Cell Panel offers a text entry field. Now, when you hover the mouse over the area occupied by comment cells you'll see your comments presented in a transitory tool-tip. This hover behavior applies even when the comments are hidden by the layer-visibility knob. If you don't like the tooltips, they can be disabled in the Layer Panel Menu.

The Challenge

The files, theChallenge.chg and theChallenge.fgrd form the foundation of this challenge which is merely to understand how this Rube Goldberg machine works. Most session files aren't this crazy but understanding this one fully will sharpen your Session-Grokking skills. Here are some tools and techniques to help you in this quest:

• SessionGrid allows you to solo a layer.
• Comments are included in theChallenge.fgrd in many places. Just hover over the cells in question.
• Other aspects of the behavior are locked up in scale.fgrd and diag.fgrd. Specifically, these files may contain sections and their associated NoteGrid file may interpret incoming Program events as section changes.
• Individual sound files can be auditioned in the Sound Player. First you must locate the Graph Node that references the sound file, then click on the view/edit icon next to its filename.
• You can audition a portion of a SessionGrid by creating/selecting a Section and entering its id into the SessionGrid node.
• You can hide/show individual subevent channels in the Layers Panel of the Grid Editor. You can also change the colors to make important events stand out.