Lesson 4

Modulation

A sound that never changes stops being interesting quickly, and drawing every change by hand is slow. The control rack is the third option: things that move on their own, pointed at anything you like.

A rack outside the tracks

The Control Rack sits near the top of the hierarchy, outside every track, and holds the things that move: LFOs, envelope loopers, CV sequencers, envelope followers and a few utilities.

None of them make a sound. They are not in a track because they are not in anyone's signal path - putting an LFO on a track would imply it was in the chain, and it is not.

Open the rack from the drawer with 7.

They write to buses, not to knobs

This is the idea worth getting straight, because it is not what the gesture suggests. A source does not connect to a control. It writes its signal to one of sixty-four numbered buses, and any control anywhere can be told to read that bus.

An LFOin the control rackwrites tobus 3one of 64a filter's cutoffreads ita track's levelreads ita visual nodereads it
Nothing joins the LFO to any of those three. It writes a signal to a numbered bus and they each read that bus, which is why one source can drive things that have nothing to do with each other - and why removing one of them does not disturb the other two.

So one LFO can sweep a filter, pulse a track's level and animate something in the visuals at the same time, and those three know nothing about each other. Point a fourth thing at the same bus and the first three are undisturbed.

Two ways to point one at a control

Drag a cable. Every module in the rack has an OUTPUT jack. Drag from it and a cable follows the pointer; drop it on any knob or slider anywhere in the application and that bus is assigned, with no dialog in between. The cable draws above everything, so it can cross a floating module window on its way.

Or right-click the control and choose CV Modulate. That opens a small dialog where you set the bus number and the depth by hand. It is the same assignment; the cable is the quick way and this is the precise one.

Right-click a jack to see what it is currently driving, and to disconnect.

Depth, and why your setting survives

An assignment has a depth from −1 to +1, and it decides how far the bus is allowed to move the control. The value you hear is your own setting plus the bus scaled by that depth.

Which is the reason for the behaviour lesson 3 described: the knob's pointer stays where you put it, because your setting is still doing its job as the thing modulation is measured from. The violet ring shows where the bus is taking it.

A negative depth simply inverts it, which is the shortest way to make two things move in opposite directions from one source.

Not every control can take modulation. Some are backed by a fixed value with no modulation input to sweep, and those will not accept a cable. The ones that do accept it show a small bus and depth readout underneath.

Sources live in the rack, outside the tracks, and write to sixty-four numbered buses rather than to any control. Drag a cable or right-click a knob to make something read one. Depth decides how far it moves and your own setting stays the thing it moves from.

That is the end of this course. You can find a module, put it in the right place, work its panel and make it move. What none of it has done yet is decide what to play, which is what the remaining courses are about.

Phonon University is free documentation from Aphelion. For the theory underneath it, rather than the application, there is Battuto.