vocal software

I want to add some backup vocals to my songs but it sounds strange having the same voice on both lead and backup. Are there any programs that allow you to change the characteristics of vocals? I tried changing the pitch and equalization but it just sounds phony and goofy.

Actually, having singers supply their own background parts is a time-honored tradition that dates back to the dawn of multitrack recording (Les Paul and Mary Ford) and remains a common practice to this day. For harmonies in particular, nobody on the planet will blend better with you than you do.

However, it is common to effect foreground and background vocal parts differently: different EQ, panning and reverb/delay.

For one thing, you usually put more reverb and/or delay on background vocals, which helps create the aural illusion that they are further back than the lead vocal.

If the background vocals are harmonies to the lead, they are usually panned slightly left and right of the lead. This helps keep them from "steppiing on" the lead and creates an illusion that all the voices aren't coming from the same place.

Background vocals often have a spectral notch cut out of them around 2-4Khz, which improves intelligibility of the lead vocal. You're basically treating the vocals as multiple instruments and carving a spectral profile for each one that lets them sit in the mix, just like you'd do with multiple guitars.

Pitch tricks are tricky. Mostly they are used to fatten a single voice to make it sound like it was double-tracked. IMO there is no substitute for real double-tracking. One pitch-related tip though: if you use V-Vocal or Melodyne to correct pitch on background parts, use the tool very conservatively. Allowing a little pitch imprecision in background vocals actually fattens them up.