Some songs require to have two foot pedals because the drummer is using a double bass drum. There is a simple attachment that will allow you to have the ability.
Just a note: I have never tried Rock Band drums so I don't know the connection area.
Step 1: What You Need
2 Foot pedals that have 3.5mm size
1 Audio splitter from Radio Shack. You should find this pretty easy for $2. This is the main thing you need. This is what makes 2 people with their own headphones listen from the same audio output.
Step 2: How It Works
The foot pedals have only one black ring at the metal connector area and Headphones have 2 (left side an right side). Headphones with mic have 3 rings.
Since the foot pedal has 1 and we are using a headphone splitter, the second ring is empty.
Step 3: Placement
1. Connect both the foot pedals to the audio splitter.
2. Plug in the audio splitter to the foot pedal connector on the drum.
3. Verify that all connections are secure and no tangled wires for optimal performance
Step 4: You Are Ready!
To verify if the double foot pedal:
1. Go ahead and start up the game
2. Play a song where the drum starts out last or later on...
3. See if both foot pedals respond.
Now you can nail those songs with a double bass! Overkill by Motorhead is no sweat or leg pain
Note: I have mod my drum even further inside so I now have2 yellow and orange cymbals. If I get the time, I will make an instructable for it but it won't have many picture because it is finished. I need to build a stand like thing that will be like a hi-hat.