Transform Window

Logic Notes

Published in SOS January 2001
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Technique : Logic Notes

Logic's Transform window is often under-used, due to its apparent complexity. John Walden explains all.

One feature of Logic that many users never dig into very deeply is the Transform window. This is partly due to the rather complex and unintuitive user interface, and partly to the rather brief and functional treatment given to Transform window within the Logic documentation. The manual tells you what options or settings are available but does not really provide any good, real-world examples illustrating why you might want to use them.

This is a shame, because, given a little effort, the Transform window provides an extremely powerful platform for editing and manipulating MIDI information. It can make doing some of the routine fixing and editing jobs that are often needed on MIDI parts much more efficient and, if used in a more experimental fashion, can provide some creative help to overcome the occasional bout of musical constipation. Therefore, the aim here is to provide an overview of the main features of the Transform window and to encourage you to explore it a little further.

Back To Basics

Essentially, the Transform window is a sophisticated MIDI data editor. It can be called up from the main Windows menu, as well as from the menus atop many of the other Logic windows. As you can see from the screenshot, it is essentially divided into four areas, arranged from top to bottom, although the 'Map' area at the base of the window is only displayed when a setting elsewhere in the window dictates that it is needed.

The uppermost block contains a drop-down list of various transform presets (the 'Humanize' preset is currently displayed in the screenshot). The presets offer a good starting point for users new to the Transform window and provide templates for editing jobs such as creating crescendos or fixing note lengths. Beneath this drop-down list is a check box labelled Hide Unused Parameters, and if you really want to get to grips with the Transform window then make sure this is unchecked. The right-hand side of the upper area of the window is dominated by three buttons labelled Select And Operate, Operate Only and Select Only -- the differences between these will become apparent below. Finally, this upper area contains a further drop-down list that allows some additional control over how the chosen editing job is eventually implemented (the Apply Operations To Selected Events option is displayed).

  Controls View Offers Extra Plug-in Parameters  
  Many of the plug-ins that come bundled with Logic Audio have two possible view options -- Controls and Editor. The Editor view is the usual virtual front panel, while the Controls view simply presents every possible parameter as a horizontal fader. Understandably, most people work in the former mode because it's easier on the eye than a host of visually similar faders. However, what may not be obvious to many Logic users is that some of the plug-ins actually provide more parameters when using the Controls view.

For example, a number of users have noticed when using Emagic's EXS24 plug-in sampler that samples sometimes play back quieter than they should. Switching to the Controls view reveals a parameter called Output Volume which is set to -12dB by default to allow for people playing masses of very loud notes at the same time. Most of the time this can be turned up to -3dB, or even to 0dB, without any distortion problems. Once you've found the right setting for a particular Program, you can update that Program to include the new Output Level value, simply by clicking the Options button in the sampler's Edit window (immediately to the right of the patch name window), then choosing 'Save Setting To Instrument'. Paul White

 
Moving downwards, the second area contains the Select By Conditions settings. The seven available settings are Position, Status, Cha, Pitch, Vel, Length, Subposition. In fact, the Pitch and Vel settings are often labelled '-1-' and '-2-' depending upon the Status setting. This Select By Conditions area, and the settings within it, allow the user to define a comprehensive set of criteria for the selection of particular types of MIDI events within a given sequence. If a set of conditions are defined here, then any editing task that is performed by the Transform window needs to operate only on MIDI events that match the set criteria. If no criteria are set (that is, the box under each heading displays the 'All' setting) then all MIDI events match the criteria and any editing operation specified will apply to all the MIDI events in the chosen sequence.

The third area of the Transform window contains the Operations On Selected Events settings. It is here that the required editing functions are defined. The six settings in this section of the window sit directly beneath their counterparts in the Select By Conditions area. For example, the first setting in the Operations section of the window is situated beneath the Position setting in the Conditions section. Therefore, if you want to edit the positions of the selected MIDI events within the chosen sequence, this Operations area is where you would define how the event's position is to be altered.

The final area of the Transform window shows the Map. The actual title at the top of this section changes depending upon the other settings in the Transform window, and in the screenshot it is titled Operation For Byte 2. The Map is quite a powerful feature. Essentially, it is a MIDI 'converter'. If you count the number of vertical columns within the Map display you will note that there are 128, numbered from 0 to 127 to reflect the full number range of MIDI data-byte values. The height of the black bar within each of these columns indicates the conversion the Map will make.

This is easier to explain via an example. Let's imagine the Map is being used to edit the MIDI velocities of selected notes. The leftmost column of the Map controls what happens to MIDI notes with an original velocity of zero, the second column controls what happeds to MIDI notes with original velocities of one, and so on up to the rightmost column which controls what will happen to MIDI notes with an original velocity of 127. By clicking and dragging the mouse on the leftmost column, the height of the black bar can be set, again on a scale of 0 to 127. If, for example, we set this to 100, what we have created in this column is a 'map' that converts any note with an original velocity of zero to give it a new velocity of 100. By setting the height of each column individually, we can effectively transform any original note velocity to any other velocity we require. As indicated earlier, the Map is only displayed when a setting elsewhere in the Transform window dictates that it is needed and, depending on what the Map is being asked to do, the details of it's display may well change slightly.

Having introduced what the Conditions, Operations and Map within the Transform window do, a discussion of the upper portion of the window might now make more sense. The functions of the three main buttons should now be clear. The Select And Operate button examines the currently selected sequence to find MIDI events that match the criteria set in the Conditions options and then, for only those events that match the criteria, the editing functions set in the Operations options are carried out. In contrast, the Operate Only button ignores the Conditions criteria and simply performs the edit Operations on every suitable MIDI event in the selected sequence. Finally, Select Only simply selects all the MIDI events that match the Conditions settings, but does not actually make any alterations to them.

The exact way these three buttons behave depends upon the setting in the drop-down list directly beneath them. For many routine editing jobs, the setting shown in the screenshot (Apply Operations To Selected Events) is likely to be what is required and, with this displayed, the three main buttons behave exactly as described above. However, as apparent from their wording, the other three options in this list (Apply Operations And Delete Unselected Events, Delete Selected Events and Copy Selected Events Apply Operations) can all have useful applications.

So, with a sequence (or set of sequences) selected and the Transform window opened, a maximum of three sets of information have to be provided by the user in order to edit the selected MIDI data. First, the user must define a set of Conditions in order to select particular MIDI events. Second, the user must specify the editing Operations (including the Map settings if required) that are to be performed on the MIDI events. Third, via a combination of the main buttons and the drop-down list beneath them, the user then specifies how that combination of Conditions and Operations are to be applied.

The Human Touch

The above procedures can be demonstrated by a simple example based on the Humanize preset shown in the screenshot. Imagine the situation where you have created a simple instrumental melody line and you wish to double it with a second instrument. Simply copying the MIDI sequence to a second track and assigning this second track a different MIDI sound can create a somewhat lifeless duo, as the timing and velocity of every note will be identical. However, if the copy of the original sequence is selected in the Arrange window and then the Transform window opened, the Humanize preset provides a means of subtly altering the position, velocity and length of notes within a sequence.

For this preset, by default, the Status Condition is set to 'Note'. Therefore, if the Select Only button was clicked, all MIDI notes within the sequence would be selected but other MIDI events would be left untouched. In the Operations area, the Position, Vel and Length settings are all set to randomly modify the original notes (for example, each of their start positions will be altered by up to 10 MIDI ticks). The Map display shows how this randomisation process is going to alter the note velocity settings. If the Select And Operate button is now pressed, all the MIDI notes within the sequence will therefore be selected, and then their start position, velocity and duration will all be randomised within the ranges set.

The screenshot above shows the sort of effect this can have. The upper of the two sequences is the original and the lower shows a copy of that sequence that has been 'humanized' by the Transform window. As can be seen, the colours of the notes within the transformed sequence are different from those in the original (indicating different velocities). The start positions and lengths of the notes have been altered (for example, the note at the start of bar three in the original sequence has been brought ahead of the beat and shortened slightly). The end result is that the impression of two different instruments playing the melody is far more realistic, as it contains the sort of timing and volume variation that might result naturally between real players.

When experimenting with this preset, it is a good idea to start with the two MIDI parts soloed and panned hard left and right. The audio effects of 'humanizing' become apparent before you can really see these differences in the Matrix Editors (I repeatedly applied the Humanize preset to make the effect visually obvious in the screenshot). Surprisingly subtle changes produce a significantly richer and more realistic sound with such melody doubling. The Humanize preset is also extremely useful for adding a little variation within drum sequences that have been entered in step time.

Of course, all this barely scratches the surface of what can be done within the Transform window. It is one of Logic's most underexposed yet useful features and, given the powerful editing options available, this is a topic that we will undoubtedly return to in more detail in future Logic Notes columns.

  How To Isolate Words Or Phrases For Synchronised Delays  
 
One of the cheesiest ever production tricks is the old chestnut of using a tempo-related delay on selected words in a vocal track, often the last word in a line. Back in the old days, that meant working out the delay time which corresponded to the song tempo, and then bringing the effects send up, and back down again, manually at exactly the right time in the song. Even though Logic makes it fairly simple to create this effect by automating the send to a tempo-sync'ed delay plug-in, there's an even simpler way to do the job that doesn't require any automation at all.

Set up another audio track next to the one carrying your vocal line, then drag a copy of the vocal part over to this new track, which for the sake of clarity we'll call the FX track. Now, use the scissors tool to separate the sections that you want to affect and the sections you don't. If you increase the track width on the arrange screen so that the waveform is clearly visible, you probably won't need to go to the waveform editor, though you can use this to tighten up the cut points afterward if you didn't get them quite right.

Now, mute or delete the sections of the FX track where you don't want to have the effect. Insert a delay plug-in (such as the Tape Delay plug-in which is bundled with Logic) into the FX track, select the appropriate note value for the delay time and set the mix to be 100 percent wet. Press Play and, as if by magic, all your chosen words or phrases will have delay added. The level of the delays can be controlled by the FX track fader, and you can even pan them to a different position compared to the original vocal track if you want to. Moreover, some judicious use of the delay's filters and a little reverb after the delay plug-in can both help produce a nicely distant effect. Paul White

 

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