A recurring question is how to use Piano roll to tweak MIDI attributes. I decided to put a copy of a recent post here so it doesn't scroll away quite as fast.
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Here's a list of the standard controllers in the format used by real band and most other DAWs:
http://www.nortonmusic.com/midi_cc.html

Just about all of the synths I've seen use the standard controllers in the same way. The ones marked UNDEFINED are often used by other devices (not synths, usually rack gear or effects) for their own proprietary settings.

All continuous controllers (or CCs for short) require two things:

1) a controller number (which defines the MIDI attribute being changed, such as volume or modulation)
Think of this as a knob on a device.. you have a separate knob for different functions

2) and a value, which defines how much the attribute is being changed
(think of this as the equivalent of how far you turn the knob)

The values range from 0 to 127, 0 being off and 127 being turned all the way up to max

For example:
CC 7 value 127 would be volume turned all the way up to max
CC 7 value 64 would be volume turned up halfway and
CC 7 value 0 would be volume turned all the way down


In piano roll you set the continuous controller from a dropdown list box at the top of the piano roll screen. (in the following picture the continuous controller is set to #7, volume). Because PGMusic chose to put the NAME of the MIDI attributes in the dropdown list box, you don't really need to memorize the CC numbers. You can just pick the attribute by name from the list, which is quite easy to do


the value is selected in the lower pane (0 at the bottom, 127 at the top)
Wherever you click on the time line is where the change will take place.
The lines in the bottom pane represent changes in volume at those positions on the time line. As you can see, in this example the volume swells up and down



As you can also see in this picture, the changes are being made to the violins track.

(thanks to Mitch C who didn't sue me for ripping off his graphic of the piano roll view. )

https://www.dropbox.com/sh/ey71h8ep047758h/AAC12jNM0Hz9Q8zsh5iDeqNHa?dl=0