A harmony processor creates one or more harmony parts of your voice. The mic is connected to the processor which will create a harmony at a certain interval, but what ever goes in, the same comes out. So if you hit a bad note, the bad note with a harmony added will be heard. Digitech is one of the forerunners of this technology. They have a new product called Vocalist Live 2, and also a Live 4 model with more features, in which both the mic and guitar are plugged in. Instead of tracking the vocal part, it senses the chords of the guitar and then produces harmonies for the vocals. You can check it out at the link below.

http://www.digitech.com/products/Vocalist_Live2/

Actually, the Eventide was out long before Digitech made bad harmonizers cheap.

Nothing will help you sing better but your time and practice. That's assuming that you want to be known for your skill and not what the engineer had to do to make you sound better. All of these tuning processes have noticable artifacts.

Eventide was the first to invent a harmonizer, called the H949, in 1975. Now days, TC-Helicon and Antares are some of the main players in that field. Digitech brought the technology to a more affordable level, which means it will not perform like the high end units. But, the new products seem promising. Due to the large scale integration on chips now days, they can pack more processing power than ever before to improve performance. The only way to tell is to actually go to a retailer and try out the different units.

anatares doesnt have a harmony processor do they? the avp doesnt really count.

If you are looking for something to make you "sing better" in a live situation, get a tc helicon voicelive. vocal FX, pitch correction, harmonies, etc. good features. If you are looking for a harmonizer, get something that eventide makes. Cuz they rule

Antares in rack form does not do harmonies like an Eventide.

On the cheap, the TC is probably the best for the money, but you better bury it is in the mix, cause it is still hokey.

The Antares product is actually a plugin called the Choir Vocal Multiplier, which is part of the Avox Vocal Toolkit. It is different than a standard harmonizer because it actually turns a single voice into 4, 8, 16 or 32 individual voices with it's own pitch, timing and vibrato. Another plugin is the Duo Vocal Modeling Auto-Doubler with variation in pitch, timing, vibrato depth and timbral variations.

I assumed that we were only talking rack mount units for some reason. Plug-in harmonizers are a whole other ball of wax.

You are right, I should have stayed with the hardware units. But, the plugins are now starting to move from the studio to live sound applications, which is great if you are a solo performer. At the moment, only some of the big sound companies seem to be trying this. Nothing is still like human vocals singing the harmonies.