I am trying to connect my guitar to my computer. I am using the Alesis Core 1 as my audio interface. It has two options: line and guitar. The guitar sound comes out of my speakers but I can't edit it through my amp simulator, BIAS. Any tips?
First you need to get the correct drivers to operate this interface. These should be the ASIO drivers supplied by Alesis, but ASIO4all might also work ok. Once the drivers are ready, you should see them in Reaper's ASIO devices list.
Next get rid of that clean signal you're hearing already. It seems a lot like you're dealing with a direct hardware monitoring feature here (“zero-latency monitoring”). Look it up in the Core11's manual how to turn this off.
Then you need to set up a track in Reaper to have BIAS running on as a plugin. you need to arm the track (red record button) and select the correct input. When playing the guitar, you should then see a peak meter on the track. Also you need to turn on the monitor switch on the channel. With that done, you should then hear the processed guitar track on the output.
Possibly there'll be some delay between the notes you play and the notes you hear. Set the latency (in the ASIO driver settings) down as low as possible. Or, in case this causes audio-dropouts, as low as you can go without these happening.