Set MIDI Transform operations parameters in Logic Pro

The Operations area is used to define the changes you want to make to events that meet the selection conditions. As with the selection condition pop-up menus, you choose an operation in the appropriate event parameter columns. One or two value fields may appear, depending on the chosen operation.

Define the operation for the status event parameter column

Open the pop-up menu, then choose one of the following operations for the Status condition:
- Thru: The event type passes through unaltered.
- Fix: The event type is altered. Choose a new event type from the pop-up menu that appears below the Status Operations pop-up menu. Choices include fader, meta, note, poly aftertouch, control change, program change, aftertouch, and pitch bend. This operation effectively converts one type of event to another.
  Note: When you convert note events, two events are created: one for the note on event, and one for the note off event.
- MapSet: Choosing this setting means that events that match the Status condition (note events, for example) are used to control the map of a subsequent operation—in the Channel, Data Byte 1, Data Byte 2, and Length columns.
  - The Data Byte 1 value selects the position in the map.
  - The Data Byte 2 value determines the value at this map position.
  Internally, Logic Pro sends a meta event pair: #123 for the position, and #122 for the value at this position. These types of meta events can also be created in other ways.

Define the operation for all other event parameter columns

In Logic Pro, choose one of the following operations in the MIDI Transform window for the Channel, First or Second Data Byte, and Length columns (as required). One or more value fields appear below the respective operations pop-up menus.
- Thru: The event passes through unaltered.
- Fix: Fixes the event parameter to the set value. You could use this to set the pitch of all note events to a specific note value, making it easy to convert a bass groove into a hi-hat pattern, for example.
- Add: Adds the value to events. For example, a value of 8 could be added to all incoming note velocity events, thus making the notes louder.
- Sub: Subtracts the value from events. You could use this to reduce all controller 10 (Pan) events, thereby narrowing the stereo spread of an electric piano part, for example.
- Min: Parameter values lower than the defined value are replaced (by this value). Larger parameter values are not altered. You could use this to replace all note velocity messages below 45, thereby reducing the dynamic range of a MIDI region—or put another way, making the soft notes louder.
- Max: Parameter values that exceed the set value are replaced by it. Smaller event parameter values remain unaltered. This could be used to restrict filter resonance modulation events above a value of 100, for example, resulting in a softer filter sound.
- Flip: All parameter values that match the conditions are reversed around a pivot point (the value defined here). Events above this value are moved by the same distance below it, and vice versa. For example, you could move a note from E3 to G#2, if the pivot point value was set to C3. Effectively, the E3 event, which is 4 (pitch) values above the C3 pivot point is flipped to 4 values below (G#2). This can also be used to reverse selected note positions around a particular bar or beat, as another example.
- Mul: The parameter value is multiplied by the set value (accurate to four decimal places). The effect, and use, of this operation is best illustrated by the Half Speed preset.
- Div: The parameter value is divided by the set value (accurate to four decimal places). The effect, and use, of this operation is best illustrated by the Double Speed preset.
- Scale: The parameter value is multiplied by the top value, and the bottom value is then added. This is a combination of Mul and Add. If you enter a negative number here, values can be subtracted from—rather than added to—the value resulting from the multiplication.
- Range: Parameter values outside the set value range are replaced by the values of the (range) limits (combination of Min and Max).
- Random: Random values are generated within the set limits.
- +-Rand.: A random value between zero and the set value (positive or negative) is added.
- Reverse: The parameter value is reversed within its value range (no value can be set here).
- Quantize: The parameter value is quantized to a multiple of the set value.
- Qua & Min: Like Quantize, but the quantization does not fall below the set value (a combination of the Quantize and Min functions, with the same set value).
- Expon.: The parameter value is scaled exponentially. The extreme values (0 and 127) remain unaltered. The set value determines the shape of the curve. Positive values result in the exponential scaling of data (increasing input values remain lower for longer, and then rise quickly), and negative values result in the logarithmic scaling of data (decreasing input values remain higher for longer, and then drop off more quickly).
- Crescendo: This only works if the Inside Position selection condition is selected (crescendos need start and end points). Crescendo creates a smooth alteration of the current parameters, between the set value boundaries.
- Rel.Cres: This only works if the Inside Position selection condition is selected. The effect is similar to that achieved by Crescendo, but the previous values of the parameters being altered are taken into account when the crescendo is created, preserving the relative feel of the original.
- Use Map: The set map is used when this operation is selected. For more information, see Use the MIDI Transform map in Logic Pro.

Set the values for an operation

Use the mouse as a slider, or enter a value directly into the field.

Download the guides:

Logic Pro User Guide: Apple Books | PDF

Logic Pro Instruments: Apple Books | PDF

Logic Pro Effects: Apple Books | PDF

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