Section 26.12. Velocity, Pedaling, and Other MIDI Data

26.12. Velocity, Pedaling, and Other MIDI Data

As you've probably started to gather by now, there's more to a musical performance than deciding which notes to play when. A keyboard player, for example, adds nuance and interest to a performance using a number of other tools. The velocity of the playing (how hard each key is struck), the pedaling (using a sustain pedal connected to the keyboard), and the control wheels (pitch and modulation) can all affect the way the music sounds.

GarageBand records all of this information as you play and lets you edit it later. The key to viewing and editing these kinds of MIDI information is the Advanced panel of the Track Editor (Figure 26-15).

Figure 26-15. To edit key velocity, first select the note or notes you want to affect, as shown here. Then, change their velocity using either the Velocity number boxtype in a new number from 0 to 127or the slider beneath it.
In notation view, there's another way: -drag the selected note(s) up or down.

26.12.1. Editing Key Velocity

Key velocity is a digital record of how hard you pressed each key when you recorded a MIDI region. On some instruments, greater key velocity just means "louder," as it does on a piano. But in others, greater velocity means "more vibrato," "crunchier sound," and so on.

Key velocity is measured on a scale of 0 to 127. That may not seem like an especially logical scale to you , but (because it's a power of 2) it's very convenient for the Mac to understand. In any case, a velocity of 1 indicates a key pressed with all the force of a falling pigeon feather; a velocity of 127 reflects the force of, say, a second piano falling onto the first. (GarageBand doesn't actually let you change a note's velocity to 0, because that would be a nonsensical value for most musical purposes.)

In the Track Editor, a note bar's color indicates its key velocity, as you can see here:

Table 26-2.

Note color	Key velocity
Light gray	031
Medium gray	3263
Dark gray	6495
Black	96127

To edit your notes' key velocities, first open the Track Editor's Advanced panel identified in Figure 26-15. Then proceed as shown in the same figure.

Note: Things can get tricky when you've selected multiple notes with different velocities. In that case, the slider and the number box show the highest key velocity among the selected notes. But as you make the adjustment, you're adding or subtracting the same amount from all other notes.If you select three notes, therefore, that have velocity settings of 20, 30, and 40, the Velocity box will say 40. If you drag the slider to shave 10 off the heaviest note, the first two notes will also have decreased by 10. The three notes will now have velocity settings of 10, 20, and 30.

By adjusting key velocities in this way, you can perform a number of different musical-surgery procedures:

Make an entire lick (short musical passage) play with more emphasis. Or less.
Change the "color" of a chord by lightening up on some notes, and bringing out others.
Add vibrato to the money note (the highest, longest, most important note) of a flute solo.
Edit an acoustic guitar part so that the sliding grace notes play only where you want them to. (When struck with a key velocity of 124 or higher, most GarageBand acoustic-guitar samples add a little sliding grace note upward from the next lower note.)

26.12.2. Editing Pedaling

If your MIDI keyboard has a sustain pedalthe electronic equivalent of the rightmost pedal on a regular pianothen GarageBand records your foot -presses right along with the key-presses. In the Track Editor, you can even see standard sheet-music pedaling marks, as shown in Figure 26-16.

You can use the Track Editor to edit pedaling you recorded during a performance, of course. But you can also use it to add pedaling to a performance that didn't have any to begin witha performance you created using Musical Typing (Section 26.3), for example, or a MIDI keyboard that didn't have a pedal.

26.12.2.1. "Drawing in" pedaling (notation view)

It's light- years easier to edit and insert pedaling in notation view than in piano-roll view, thanks to the prominent Ped . markings that indicate when the pedal was pressed. (Note to all beginning piano students: No, it's not a cute little doggie . It's just Ped . in a very fancy font.)

If you'd like to experiment, create a new document and insert the loop called Upbeat Electric Piano 03. Its notes are short and sharp, so you'll hear a clear difference when you start adding the sustain pedal.

Then see Figure 26-16 for the details.

Figure 26-16. "Drawing in" pedaling is easiest in notation view, because you're dealing with standard pedaling symbols instead of bizarro up/down graphs.
Adding a new "press" of the pedal is a three-step process, as shown here.

26.12.2.2. "Drawing in" pedaling (piano-roll view)

If notation view isn't your thing, here's how you edit pedaling in piano-roll view:

Open the Advanced panel of the Track Editor .

You can see the little triangle to click for the Advanced panel in Figure 26-17.
From the Display pop-up menu, choose Sustain .

You've just told GarageBand which kind of invisible MIDI data you want to change.

While pressing the key, click a spot along the light gray, top line (labeled 1 in Figure 26-17) .

GarageBand creates a round handle at the point you clicked. You've just created a "sustain pedal down" event where none existed. (Technically, you can click anywhere in the upper half of the Track Editor window, since GarageBand "rounds off" your click to the top line to indicate a full press of the foot pedal.)

If you play back your region at this point, you'll hear all the notes get "stuck" at the point where you created the pedal-down event. Unless you enjoy the cumulative, mushy, clashing sound of every note in the piece being held down forever, find a spot to release the sustain pedal.

Note: As with key velocity, sustain-pedal motion is recorded on a scale of 0 to 127. Unlike key velocity, however, there's no such thing as a sustain-pedal setting between 0 and 127. After all, in the real world, there's no such thing as half -pressing the pedal on a piano. So every value is either 0 or 127which GarageBand tries to simplify by labeling the lines 0 and 1and your pencil cursor will snap either to the "up" line or the "down" line.

Figure 26-17. Don't be fooled: When the line is up, the sustain pedal is down, and vice versa. In the world of MIDI software, this particular graph is upside-down from the physical controlthe foot pedalthat generates its data. That is, up is "on," and down is "off."

Move the cursor to the right, and then -click a spot on the bottom gray line .

Another round handle appears, this time indicating where your virtual player should take his foot off the pedal. A quick playback will prove the point.

26.12.2.3. Editing existing pedaling (notation view)

You can change the pedaling by dragging the Ped . (pedal pressed) and * (pedal released) symbols right or left in the sheet music. You can also delete an entire pedal down-up sequence by clicking either one, so that the dotted line appears, and then pressing the Delete key.

26.12.2.4. Editing existing pedaling (piano-roll view)

If you've ever edited volume levels of an iMovie video soundtrack, these round handles should seem familiar. They're audio control points, which you can slide around to fine-tune where they appear.

For example, here's what you can do with pedaling points:

Drag a handle right or left to change when the pedaling takes place. The control point directly above or below it, if there is one, goes along for the ride, because it takes two to represent one movement of the pedal.
Click a handle and then press Delete to eliminate that handle and the one directly above or below it.

As you'll quickly discover, clicking one handle also highlights the one vertically in line with it. For example, if your pedaling map now looks like Figure 26-17, deleting the second pair of vertically aligned points will merge the first pedal-press "mountain" with the second one. You'll be left with a single, but longer, pedal-press.
-click the top or bottom line to introduce a new control point.

26.12.3. Editing Control Wheel Data

Many MIDI keyboardsincluding the $100 M-Audio keyboard that Apple sells as a companion for GarageBandhave one or two control wheels at the left side.

The pitch wheel lets you bend a note higher or lower in pitch (like a blues harmonica). Its sibling, the modulation wheel , can do a variety of things, like add a sweet vibrato to the sound, change its character, or do nothing at all, depending on which instrument sound you've selected. See Section 26.9 for more on using control wheels.

UP TO SPEED
Beyond Pitch Bend

It's kind of neat that GarageBand records, displays, and edits streams of MIDI information like pitch bend, key velocity, and pedaling. But in the real world of MIDI, those kinds of data are only the beginning. Professional music software can record and play back dozens of other kinds of invisible MIDI data.

Aftertouch, for example, is a measurement of how much pressure you apply to a key after you've pushed it down. Of course, a real piano doesn't respond to aftertouch at all; once you've pressed down a key, pressing harder doesn't give you anything but a thumbache. But on some synthesizers, bearing down harder on a key after it's already down triggers, say, the vibrato sound on a trumpet .

Program Change data lets you switch to a different synthesizer sound in mid-performance. Breath controller data is generated by a special attachment that, yes, you breathe into, giving you yet another way to change the "shape" of the sound.

GarageBand doesn't record or let you edit these MIDI data types (not that most GarageBand musicians would even care).

Here again, the Track Editor lets you edit any pitch wheel or mod wheel information you generated while recording. It even lets you " turn " one of those wheels after the fact, even if you don't even have a keyboard with control wheels.

To inspect your control wheel data, open the region in the Track Editor, open the Advanced panel (Figure 26-15), confirm that you're in piano-roll view (not notation view), and from the Display pop-up menu, choose either Pitchbend or Modulation.

If pitch wheel or mod wheel information is already a part of the recording, you'll see something like Figure 26-18.

Note: As shown in Figure 26-18, pitch wheel effects usually involve turning the wheel in between notes, getting into ready position, and then releasing it, so that it returns to its spring-loaded "at rest" position during a note. Or you can do the opposite : Press a key, turn the pitch wheel up or down, and then release both together. Either way, don't be fooled by the up-down and down-up "hills" graphed in Figure 26-18; half of each "hill" actually takes place during the silence between notes.Most people turn the mod wheel, on the other hand, both up and down during a single note (to make the vibrato gradually begin and end, for example).

Figure 26-18. When you're viewing pitch wheel information, as shown here, the ruler scale goes both upward and downward from 0, because a pitch wheel's "at rest" position is in the middle (see Figure 26-9). You can turn it either up or down. A mod wheel's "at rest" position, though, is turned all the way down, and you turn it only upward, so its scale goes from 0 (at rest) to 127 (all the way up).

Pitch-wheel data is represented on a scale of 0 (when you're not touching the wheel) to positive or negative 63 (when you've turned the wheel as far as it will go). The mod wheel's scale goes from 0 (at rest) to 127 (turned all the way).

In the case of the pitch wheel, each notch (from 0 to 1, for example) represents one half-step, which is one adjacent key on a piano keyboard. That's useful to remember if you're inclined to add pitch-wheel data to a recording manually (because your keyboard doesn't have wheels, for example).

Once you've got that fact in mind, the techniques for adjusting or creating wheel control points are very similar to the methods for working with sustain pedal data:

-click in the Track Editor to create a new round control handle. This is how you'd start "turning" the wheel during a note even if you don't actually have a keyboard with wheels.
Drag a control handle horizontally to change its timing, or vertically to adjust the intensity of its effect. (Again, 0 means "wheel is at rest.")

Select a group of control handles to move them all at once; drag any one of them as a handle.

This tactic is especially useful when you want to edit pitch-bend or mod-wheel data in a track that you recorded live. As shown in Figure 26-19, using a control wheel during a live performance generates a torrent of control handles. Turning the wheel smoothly and gradually, as you would in a live performance, spits out dozens of control points (0-3-5-11-22-24, and so on). By dragging a whole batch of points at once, you can adjust the timing or intensity of a wheel turn with a single drag. The selected points retain their spatial relationship as you drag them.

Figure 26-19. Most instruments' vibratos sound most realistic with the mod wheel turned up only part wayabout 50 or so. For added realism , make the vibrato begin and end gradually, and don't begin the wheel turn until a moment after the note has been struck.

Delete a turn of the wheel by selecting all of the representative control points and then pressing the Delete key.

26.12.4. Control wheels: do-it-yourself

If you'd like to experiment with control-wheel data, create a new GarageBand project. Double-click the icon of the Grand Piano starter track, scroll down to Woodwinds, click Pop Flute, and then close the dialog box. (A flute is a great sound for testing control wheels, because its notes are long and sustained so you can hear the effects over time.)

Now open the miniature GarageBand onscreen keyboard (choose Window Keyboard, or press -K). Press the letter R key on your keyboard to begin recording, and hold down a long noteC4, for exampleon the little onscreen keyboard. Press the Space bar to stop recording after a few seconds of that note.

Now double-click the new green region to open the Track Editor. Make sure the Display pop-up menu says Notes. Zoom in until the note bar you recorded stretches across most of the screen.

Change the Display pop-up menu to say Pitchbend. Now, starting at the 0 midline, go nuts -clicking control points into a hilly shape, as shown in Figure 26-18. When you play this back, you'll hear the gradual bending of the note over time.

You can repeat the same experiment with the modulation wheel. But this time, start your "hill" from the 0 line at the bottom of the graph, as shown in Figure 26-19. You'll hear your virtual flutist add a gradual vibrato to the note as the "hill" of your mod-wheel graph gets higher.

26.12.5. Importing MIDI Files

Graphics programs can exchange documents in the form of JPEG files. Word processors can exchange text files. Web-design programs can swap HTML documents.

And in the musical world, the common exchange format for finished musical masterpieces is the MIDI file. It's a compact little file that contains no sound datajust note-trigger data that relies on a computer or synthesizer to give it a voice. Hundreds of thousands of MIDI files are all over the Internet, just waiting for you to download. Just go to Google.com, type in MIDI files "76 Trombones" or whatever, and in a matter of seconds you've got a list of instrumental versions of that song, arranged and prepared by amateur or professional musicians, ready to download.

Tip: When you click a link to a MIDI file on a Web page, it generally begins to play. That's not the same as downloading the file. In that situation, hit your browser's Back button. This time, Option-click the original link. (Alternatively, Control-click the link and choose from the shortcut menu, "Download Link As" or "Save Link to Disk.") This time, instead of playing the MIDI file, your browser downloads it to your desktop.

The beauty of downloading MIDI files (apart from their being free) is that you can work with them in your music software. You can import a favorite song into GarageBand, substitute high-quality Software Instrument sounds for the cheesy QuickTime sounds that you hear when you play them online, redo the orchestration by assigning different instrument sounds altogether to each line, add some live recordings to boost the realism, and so on.

This vast Web library of ready-to-play music is ideal for exploits like practicing, karaoke , serving as background tracks for imovie movies and iPhoto slideshows, and so on.

For the first time, GarageBand 2 can directly import MIDI files, so that you can dress them up with effects, add GarageBand's great-sounding drum loops , record some live tracks like vocals, and so on. Figure 26-20 shows the details.

Once GarageBand is showing the imported musical material, you can play it back, change the tracks' instrument assignments, or adjust the tempo or key. (Most MIDI files "know" where their own beats and measures are, so that adjusting GarageBand's tempo correctly speeds up or slows down the MIDI data.)

Figure 26-20. Top: Import a MIDI file by dragging it into an empty spot in the timeline (or into a green Software Instrument track).
Bottom: After a moment, GarageBand displays the component tracks of the MIDI file. It should sound pretty OK right away, but most MIDI files become dramatically better once you've spent some time reassigning them to GarageBand's more realistic-sounding instruments.