free voice changing

Any free computer programs for changing voice for singing?

I was wondering if anyone knew of some free computer programs where you can modify/distort your voice a little bit. I wasn’t really looking for anything like autotune but if it includes that too it’d be cool. I’m looking more for something that has like an echo like I’m talking in a tunnel. Anyone know some good programs?

Audacity is a good program… But you have to stop the track to add effects…. Reaper lets you edit while the track is playing. Makes it go much faster and you get instant results. I record with Audacity because my microphone has a delay with Reaper, then I transfer to Reaper to edit and mix.
http://www.reaper.fm/ Its free.
This is my band page. http://www.reverbnation.com/#p=/5string Check it out if you have a sec.
Dal (vocals)

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free voice changing