Guitar Hero/Rock Band wireless keyboard

The old RB2 cymbals are just for show - they don't add anything to the game. Hitting the green cymbal, for instance, is the same as hitting the green pad.

However, the new RB3 cymbals serve a real purpose - they allow you to play in the new "Pro Mode," in which you are required to differentiate between hitting the cymbals and the toms!

Here you can see the pro-mode drums being played with cymbals (middle track). The green and blue ovals coming up are cues to hit the green and blue cymbals, respectively. The usual blue rectangles coming down the screen are the cue to hit the blue tom instead.

Note that this image also shows pro-keyboard (left) and pro-guitar (right) as well. (Credit to IGN for the image)

There's a brilliant tutorial on completely manual calibration here by a pro-level RB player:

I can't express enough how useful this video is. Even if you think you know everything there is to know about this topic, it's worth a watch.

How to calibrate, per this video:

1. Completely turn off audio (set volume to 0), so you can focus on the video and hitbox.
2. Go into quickplay and hit purposely early and late to figure out where the hitbox is for you. How early can you hit? How late can you hit? That's the size and position of your hitbox!
3. Based on your measurement of the hitbox, move the hitbox using the positive video bias (towards you) and negative video bias (away from you) to get a centered hitbox that allows you to hit equally early and equally late
4. Now it's time to focus on the audio.
5. Ideally this takes two people and a simple song with a steady beat; one person closes their eyes and plays to the beat, the other person observes to see if you are hitting early or late. I know, this sounds freaky, but per the author, this is very very difficult bordering on impossible to do by eyeballing it solo.
6. If you are hitting early, set negative audio bias to compensate. If you are hitting late, set positive audio bias to compensate.

Warning: different types of instruments may have different lag -- wireless/wired, guitar vs drums vs keyboard, etc. There's only one global audio/video lag setting, no way to set it per instrument. Thus, you should think of the hitbox as the "all controller" compensation area you use to deal with this.