Update: several readers let me know there was an easier way to add these instruments. By selecting Keyboards, you can tap on the Tool button in the upper right corner of your screen. At the bottom of the Tool menu, tap Advanced, and simply activate Chinese Instruments there. Easy, right? Jeff Gamet made a great how-to video for us, which I'm including below.

I'm also leaving the original article below for posterity's sake.

Apple added several Chinese instruments and some 300 loops of Chinese music to GarageBand this week, but you'll need to jump through a couple of hoops to access them on iPad and iPhone.

On the Mac, it's simply a matter of downloading them on GarageBand. The loops and instruments appear in the loop browser grayed out with a download icon next to them. Click any of them and they all download.

GarageBand for iOS, on the other hand, requires you to enable a Chinese keyboard in Settings -> General -> Keyboard. Once you do, you'll see the erhu, pipa, and Chinese drums, as well as all the loops. It's pretty simple, but here are some screenshots for the quick and dirty low-down.

Firstly, make sure you've updated to the most recent version of GarageBand. For some reason, my iPhone saw the GarageBand update, but my iPad didn't. I had to go grab it from its App Store listing. Once installed, the Chinese drum "set" appears automatically, without enabling the keyboard. Whether that's a feature or a bug is up to you.

Chinese Drums on last page of Drums

But you'll notice there's no ehru or pipa in my instrument browser, even though I've updated GarageBand.

Normal GarageBand instrument browser

Off I go to Settings -> General -> Keyboards -> Add New Keyboard -> Chinese (Traditional) -> Just Pick One. You could also use a Chinese (Simplified) keyboard. Whatevs.

I randomly chose Chinese (Traditional) Pinyin- QWERTY.

Now let's look at the instrument browser in GarageBand. What's this, the erhu? Why yes. Yes it is!

Erhu

And the pipa!

Pipa

Tapping the pipa from the browser gets me this window where I can start playing as if I actually understand the Chinese pentatonic scale. Yay me!

Pipa Instrument Interface

Unfortunately, you'll need to leave the Chinese keyboard enabled to maintain access to these instruments. In our tests, they went away once the keyboard was disabled. It's not like it gets in your way, though, so it's not likely to be a nuisance. Hopefully Apple changes this in the future.

Lastly, a hat tip goes out to iPhonedo on YouTube. In his demonstration of these new instruments we ran on Wednesday, he showed us how to get the instruments by switching our iOS device over to the Chinese language. That works, but only because it ALSO enables a Chinese keyboard, something Adam Christianson of MacCast figured out for us. The key being the keyboard, not the system-wide language choice.