Fig. 7. Garritan’s Aria engine has an intuitive, friendly interface that belies the program’s power.

GPO4 uses Garritan’s Aria Player (Figure 7, VST/RTAS/AU/standalone); the sample library is just shy of 2GB. The key word here is value—there’s a full range of orchestral instruments, with excellent recording quality and expressiveness, at a fraction of the cost of the “big guys.”

So what do you give up? In terms of end result, not much. Granted, there are fewer samples, and the high notes on some instruments aren’t quite as “sweet” as some other libraries. But you still have instruments with keyswitching options to add expressive flourishes, and there’s intelligent use of the mod wheel to add “one-stop” expressiveness— proper mod wheel manipulation can add real magic, especially to solo instruments. Compared to previous versions of GPO (upgrades are $49), there are additional sounds (choir and stronger brass presets), an autolegato function that detects your phrasing, integrated ambience, and compatibility with Scala definition files for non-standard tunings.

GPO also does something that’s a bit brave: The sounds are recorded dry, so they don’t sound lush and symphonic “out of the box.” Of course, you can add ambience with the internal options, but more importantly, if you have a favorite ambience plug-in you can use it without interference from existing ambience.

You also get some perhaps unexpected features: 64-bit support including Windows 7, compatibility with Steinberg’s VST Expression functionality, light CPU footprint, optimization for Akai’s EWI wind controllers, 16 stereo outs, EQ and instrument controls for each loaded sound, warm ambience, and integration with notation programs (e.g., Finale 2010 or Sibelius 6.1—you can install GPO4 as a standard version, a version for use with notation programs, or both).

GPO4 is an overachiever. It may not be impressive when you first start loading instruments, but that’s misleading: Once you get the mod wheel, keyswitching, and ambience sorted out, the sounds truly come alive—just ask Terry Lawless (keyboards for U2), Wendy Carlos, or J. J. Abrams (Star Trek, Lost). And GPO4 doesn’t exist in isolation; Garritan’s website offers free, interactive orchestration and jazz arranging courses, a focused and friendly forum that’s loaded with tips, and solid support. For orchestral sounds, GPO4 is a great deal—and a program that was obviously put together with both care and pride.