Using Garritan Personal Orchestra (GPO) with
MOTU Digital Performer 4.12 (DP4)

by Brian Monroney

This is a quick tutorial on how to use GPO in DP4; it assumes that you are already somewhat familiar
with DP4, that GPO is properly installed, and that your audio and MIDI hardware is already configured
and working correctly.

1. Create a New Project in DP4. Use the New command on the File menu or press Command-N.
DP will ask you for a location to save the project folder.

2. From the Project menu in DP4, select Add Track -> Instrument Track -> Garritan Personal
Orchestra (Stereo). The GPO Plugin interface will appear.

3. If you know what sounds you’ll be using, go ahead and load them now. For this example I
loaded the Flute & Piano Multi, which includes the Steinway Piano and three flute instruments,
assigned to receive on MIDI channels 1 thru 4.



4. From the Project menu, select Add Track -> MIDI Track. Alternately you can press Cmd-Shift-
M. Hold down option while selecting any Add Track item to add multiple tracks (or, for
multiple MIDI tracks, use cmd-option-shift-M).



4. Now assign the output of your MIDI track(s) to GPO. Use the MIDI track’s output pop-up
menu, which is available in three places: the output column of the Track Overview window
(shown below), the Mixer window, or in the left column of the Sequence Edit window.



5. The MIDI track must be record-enabled in order to play the GPO instrument from your MIDI
keyboard. Below you can see I have four MIDI tracks, assigned to different channels
corresponding to the four sounds that I loaded in GPO. The Piano track is record-enabled.



Troubleshooting: If you don’t hear any sound from GPO when playing your MIDI
keyboard, here are a couple of possible solutions: First, remember that Mod Wheel (MIDI
CC#1) is used for dynamic expression in GPO wind and string instruments, so try pushing
your Mod Wheel up halfway and see if that makes a difference. If GPO is still not responding,
check the MIDI thru settings: on the Studio menu, select “MIDI Patch Thru...”, and confirm that
“auto-channelize” is enabled. While you’re there, enable the “patch thru in background”
option so that even when DP4 is not the front-most application, you will be able to play your
MIDI or virtual instruments.



You can now record and edit your music. In order to ease the load on your CPU when you are using
multiple instruments in GPO, I suggest loading the dry version of each instrument and applying a global
reverb via an Aux Track in DP4 . The excellent “Ambience” reverb plugin included with GPO is a VSTformat
plugin, which is not directly compatible with DP4, but the maker of Ambience has created an
Audio-Units verison as well, which can be obtained here:

http://magnus.smartelectronix.com/

It’s donation-ware, so if you like it, send Magnus some cash! My favorite reverb plugin for GPO is
“Altiverb”, a remarkable convolution reverb from Audio Ease, but if you don’t own any third-party
plugins you can try the free Apple Audio Units plugin “AUMatrixReverb”. The standard MOTU reverb
plugins included with DP4 are inferior to these options IMHO.

This is how you configure a send reverb in DP4:

1. From the Project Menu, Add Track -> Aux Track



2. Assign the input of your new Aux Track to a Stereo Bus. Click on the input column in the
Tracks Overview (or the Mixer or Sequence Edit windows) and create a new Stereo Bus
bundle if you don’t have any already setup. I’ll use Bus 1-2 for this example.



3. Now in the Mixer window, insert a Reverb Plugin in one of the Aux Track’s inserts:



4. Assign the Sends in your GPO Instrument Track to the Aux Track with your Reverb plugin -
unfortunately DP does not support stereo sends, so you must create two mono Bus bundles,
corresponding to each channel of your stereo reverb bus: Bus 1 and Bus 2. Use the pop-up
menu next to the topmost track send knob to assign send 1 to Bus 1:



Repeat with send 2, assigning it to Bus 2. Now turn the knobs up to 12 O’Clock as a starting
point. HINT: holding the option key while dragging any send knob in DP4 will move it’s
‘partner’ send at the same time, making it easy to match the send amount on each side.

Once you finished inputting and editing your work and have it tweaked to perfection, you will
probably want to render it as an audio file in DP4. The easiest way to do that is to assign the output of
your GPO Instrument Track to another stereo Bus, then create a Stereo Audio Track (once again,
you’ll find your track-creation commands on the Project menu -> Add Track). Set the input of the new
audio track to the same Bus. Record-enable the audio track, and now when you press Record, the
output of GPO will be recorded into this track.

You can monitor the level of this internal bounce from the Audio Monitor window (you may need to
scroll down to see the record-enabled Bus, hi-lighted in red. In the screen-shot below, I have GPO
assigned to Bus 3-4; “Audio Track 6” is recording GPO’s output, and I have another Aux Track
configured so that I can hear the output of GPO while recording (“Bounce Monitor”). You can also
use the Audio Patch Thru features in DP4 to monitor what you’re recording, but I like the flexibility of
creating a dedicated path for monitoring.



Brian Monroney, June 2004