Greetings, I am fairly new to Reaper, and think its an AMAZING program. I was wondering if anyone could give me any insight into how I would perform key ducking in Reaper, I've tried it, but cannot seem to get it working. Also another unrelated question about the world of Pro Tools. I don't understand how Pro Tools can make any compressor act as if it has a sidechain, but this is not possible in any other DAW...is this due to the RTAS standard? Thanks!

If the plugin supports sidechain, as reacomp does, you can do it that way. If not, or for more effects, you can use the parameter modulation feature

EDIT: I found a great explanation on how to complete ducking. The instructions are as follows: 1) Create a new track and make it a folder track. Make it have 4 track channels (in the I/O panel) 2) Move the track that you want to duck (bass) within that folder 3) Move the track you want to trigger the sidechain with (kick drum) above the folder track 4) Send the kick drum to input 3/4 of the folder track 5) Add ReaComp to the folder track and change the Detector Input to "Auxiliary Input L+R" 6) Click on the 4 Ins button and make sure that Main Input L receives from track 1, Main Input R receives from track 2, Auxiliary Input L receives from track 3 and Aux Input R receives from track 4