Assignment 3: Short Piece
What we’re trying to do
Make a short composition using audio in Digital Performer. It should:
- last two to three minutes,
- build on skills you learned in the first two assignments,
- include volume and panning changes,
- include time-scaling and pitch-shifting,
- include EQ (equalization), reverberation, delay, and other real-time
What to turn in
- One Digital Performer project folder, with the assignment number and
your login as part of the folder name. Keep this project in your account
on the MAC 304 computer. Do not submit it in Canvas.
- One WAVE (or AIFF) file containing the final mix (created with the
Bounce to Disk command). Name the file with your piece title.
- Write a short description of your piece. Include the title of the
piece and a few sentences about how you made it, what it’s about,
and so forth. Say what you like best about the piece, and what you want a
listener to notice. You will submit this text along with the bounce file
in the next step.
- Follow the assignment submission
instructions to submit your mix file (WAVE or AIFF) and your
project description using Canvas.
After you turn it in
- We will play your compositions in tutorial.
- These projects will receive letter grades.
- Grades will be based on overall conception and execution, the quality
of the source recordings, your sonic imagination, attention to detail,
sensitivity to spatial (panning, reverberation) and spectral (EQ)
qualities, following the instructions (including submission requirements),
and completion of the project description.
The basic idea
You are to create a piece using only sounds you record yourself. (You may
use any of the sounds you recorded for Assignment 1, plus any more that
you’d like to record.)
Please DO NOT use any of the following for this assignment:
- sounds from synthesizers or samplers,
- sounds copied from sound effect CDs or audio CDs,
- sounds copied from Internet sites,
- finished passages of music played on instruments (isolated sounds are
- passages from recordings of your own acoustic pieces.
This may seem restricting, but you can do a lot with just a small collection of
sounds, if you take advantage of the time-scaling, pitch-shifting, filtering,
and other effects in Digital Performer.
One possibility to consider is the imposition of pitch onto sounds, even those
that seem not to have any pitch. One way to do this is with tight band-pass
EQs, such as in the Periscope plug-in. Another way is to use a resonating
delay line (a delay with high feedback and delay times less than
50 milliseconds). If a sound already has pitch — and is monophonic,
and cleanly recorded — you can use the DP pitch automation to change its
Below are descriptions of techniques you should perform while in the process
of building your project.
Time-Scaling and Pitch-shifting Audio
Digital Performer lets you change the duration of a soundbite without changing
its pitch, and it lets you change the pitch of a soundbite without changing its
duration. This is different from the way most samplers work, where
transposing a sample also changes its duration.
To time-scale a soundbite...
- Open the Sequence Editor (Project menu).
- Move the mouse over either edge of the soundbite — over the top
of the soundbite rectangle. The cursor changes to a hand.
- Click and drag to stretch or shrink the soundbite horizontally. When
you release the mouse, Digital Performer creates a new time-scaled sound
file (in the Audio Files folder) and replaces the soundbite you dragged
with one referring to the new sound file. This process takes a moment,
during which time the waveform appears hollow, and the soundbite will be
silent if you play the sequence.
To pitch-shift a soundbite...
- Select the soundbite, and choose Region > Transpose.
- Make sure the Transpose Audio check box is ticked.
- Just below that, choose Transpose audio by creating new
- Specify an interval of transposition, using the from and
to fields. (Highlight a field, and play a note on a MIDI
keyboard to set a pitch.)
- Press the Apply button.
Note that this type of transposition preserves formant frequencies.
Don’t expect time-scaling by large percentages or transposing by large
intervals to sound natural. But sometimes, unnatural is good.
The Spectral Effects menu command combines time-scaling and
pitch-shifting with formant-shifting. Go ahead and play with it.
Digital Performer has two methods of transposition. The default
“PureDSP” method works well for cleanly-recorded, non-reverberant
sounds containing a single pitch or melody. (That is, it works for monophonic,
not polyphonic, sounds.) This method lets you shift formants independently of
pitch, using the Spectral Effects command. The other method does not handle
formants in any special way, but it works better with sound files that are
polyphonic or contain reverberation. If the result of the default
“PureDSP” transposition sounds garbled, you can arrange for a
soundbite to use this alternative method of transposition. This setting is
buried in the Sound File Information window (Studio > Sound File
Volume and Pan Automation
You can change the volume and panning of a soundbite while it plays. You do
this either with the Mixing Board, or by manipulating “rubber band”
lines in the Sequence Editor.
Here’s how to do it in the Mixing Board.
- Open the Mixing Board (Project menu).
- Press the automation record-enable buttons for the tracks whose
volume or pans you wish to vary. (These buttons turn red.)
- Play the sequence. (That’s right: play, not record.)
- Wiggle the knobs and slide the faders, as you desire.
- Stop playing the sequence, and turn off the automation record-enable
buttons, so as to prevent accidental changes.
- Now when you play the sequence, the faders and pan knobs will move,
as long as the automation play-enable buttons are depressed.
(These buttons turn green.)
Here’s how to change volume using the “rubber band” lines.
- Open the Sequence Editor. At the left of each track is a control panel.
A pop-up menu lets you select different editing modes. Normally
you’ll see Soundbites here. This mode lets you drag your
soundbites around and edit them.
- Choose Volume from this pop-up menu. Now any soundbites in the
track are dimmed, and you can use the pencil tool to draw a volume line.
(If you don’t see the Tool palette, choose Tools from the
Studio menu.) The volume line works by “connecting the
dots.” You supply the dots, and the program draws lines between
them to ramp the volume from one state to another. Digital Performer
calls one of these dots an audio volume event, which you can
edit very precisely in numeric form.
- The volume lines you’ve drawn may display as dotted lines. This
means that automation is not play-enabled for that track. If you
play the track, you won’t hear any volume changes. You can
play-enable automation using the Mixing Board (as described above), or
you can use the handy Auto pop-up menu in the Sequence Editor
- You can drag the dots around to change the shape of the volume line.
Click on a dot and press the delete key to delete it.
The audio volume event values are expressed in decibels
(dB). A value of
0 dB means the audio plays from the disk with no amplitude scaling. If
you shape the line so that it goes above 0 dB, the audio samples will be
multiplied by a factor greater than one, and you could easily cause clipping
(digital distortion). If this happens, the track’s meter in the Mixing
Board will show it.
Panning works similarly to volume:
- Choose Pan from the same editing mode pop-up menu from which
you chose Volume.
- Shape the line just as you did for the volume line. To pan to the left
channel, drag a dot to the top of the graph. To pan to the right
channel, drag to the bottom. The vertical center of the graph
corresponds to the center of the stereo field.
from the editing mode pop-up in order to edit
Shortcut: Hold the option key down while selecting an editing mode (e.g.,
Soundbites, Volume, Pan) from any audio track’s popup menu: all
tracks will change to that mode.
One of the great things about using audio in Digital Performer is that you can
use audio effects.
To use an effect on a track...
- Open the Mixing Board.
- Choose an effect from one of the insert pop-up menus at the top
of the Mixing Board for one of the tracks. This is a little confusing,
- you might not be able to see the top of the Mixing Board (scroll
the view up to see the top), and
- these pop-up menus start out blank, as in the graphic below.
Just press and hold the mouse button on one of the arrows, and
you’ll see an effects menu. Choose an effect.
There are five vertically arranged effect slots for each track. The audio flows
from the top insert to the one below, and so on, down through all five. So if
you have a Chorus effect in the top insert, and an Echo effect in the one below
that, the dry sound from the track will be chorused first, and then echoed.
Switching the order of effects often gives you a different result.
Most effects have a wet/dry mix control that governs the amount of
effect you hear. All effects have a bypass button; toggle this to
compare the dry track with the “effected” track.
You can move an effect from one insert to another in the same track, or in a
different track, by holding down the command (Apple) key while dragging the
effect name in the Mixing Board. Hold down the command and option keys while
dragging to copy effect settings. Click the effect name while holding down the
option key to bypass (temporarily disable) the effect.
The best way to get started with effects is to try the presets that most of
them include. Select these from a pop-up menu, as shown below.
A real-time effect assigned to a track affects the track for the entire
duration of a sequence. You can apply an effect to a single soundbite by
selecting the soundbite and choosing the effect from the
Audio > Audio Plug-ins
menu. This creates a new soundbite
with the effect applied; it leaves the original soundbite alone. This is
sometimes a good thing to do, if you want just one soundbite to have an effect
but don’t want anything else in the track to have the effect. However,
you lose the benefits of real-time audio effects: effect-setting automation,
easy changing of settings, and chaining of effects.
Automation works for most real-time effect settings. Use it just like the
automation of volume and pan: record-enable automation, then change effect
settings while playing the sequence. Digital Performer remembers your setting
changes. You can edit these in the Sequence Editor the same way you edit
Using a Master Fader Track
When mixing, you should make sure that none of the tracks clips
that is, that none of the track meters in the Mixing Board light up the red
But even if you have no clipping at channels, it’s still possible for
the combination of all your channels — the addition of these
signals into a stereo mix bus — to result in clipping. The only way to
see this, and to do something about it, is to use a master fader track.
Create a master fader track by choosing Project > Add Track >
Master Fader Track. This track holds no soundbites. It merely gives you
a single volume fader that controls all of your audio tracks together. Adjust
this fader while playing your sequence so that the meter for the Master Fader
track, shown in the Mixing Board, never turns red.
Bouncing to Disk
Here’s how to get your audio into a form from which you can make audio
CDs or MP3s.
- Make certain all audio track outputs are set to Analog 1-2.
- Select all the audio tracks you want to include in your mix file.
Shift-click the track names in the Tracks view to select them. You
don’t have to include the Master Fader track in the selection.
Your audio tracks — and the Master Fader track — must be
- Use the Selection Information view (Studio menu) to fine-tune
the time range you want to capture. Usually, you’ll want the
entire length of your sequence, plus a few extra empty measures to
accommodate any reverb or echo ring-off.
- Choose File > Bounce to Disk. Use the following settings in
the dialog that appears.
- File Format: Broadcast Wave, Interleaved
- Channels: Stereo
- Resolution: 24 Bit Integer
- Import: Do not Import
- Source: Analog 1-2
If you choose Deinterleaved, you will get a pair of mono files with
.L and .R suffixes. This is not what you want for stereo.
- Press the Choose Folder button, and navigate to the Desktop.
- Press OK. Another window will pop up, but you can just OK it.
Your mix file will appear on the Desktop.
Some Sound Modification Tools
Here are some programs that let you change sound in ways not easily achieved
inside Digital Performer.
If you want to use these on your own computer (Mac only),
- right-click on a program link, choose Download Linked File As,
and save it on the Desktop, then
- double-click the .zip file to uncompress it. Open the folder to find
the program. You don’t have to install this anywhere special.
If you want to run these programs on the computer in MC 304, then it won’t
work to download them, because you don’t have sufficient permission to
run the programs. Instead, look in “/Applications/jgapps” for the
programs, and run them from there.
These programs let you import an audio file, process it, and then
record the results into another file. Then you can add that to your
Before working with these, you’ll need to click the Audio Driver
button at the top-left corner of the window, and choose CoreAudio MOTU
Traveler from the Driver pop-up menu. Then close the DSP Status
To use, first click the speaker icon. Drag a sound file onto the Play
button, check the Loop box, and press Play. Fiddle with the
controls. If you like the sound, press Record to start real-time
recording of the output to a sound file. Press the right-hand Stop
button to stop recording.