Been messing with the Harmonist digital effect pedal (from my Boss GT-1 guitar multi effects processor)
How do I make it work correctly?

From what is shown, there are the following options:
- Harmony (Unison, +/- 2, +/- 3, +/- 4, +/- 5, +/- 6, +/- 7, +/- 1 octave, etc.)
- Direct Level (not sure what this is for)
- Pre-Delay (I have some idea of this, I think it works similar to delay pedals)
- Feedback
- Effect Level (probably how loud the effect is heard when mixed with the original sounds?)
- Key (C(Am), Db(Bbm), [...] B(G#m))

Thing is, I have no idea what I'm doing wrong. If I set it to play in the key of C, and I play a scale in C, then try to add the Harmonizer effect to it, it ends up sounding like the harmony is not in the right key, or just sounds nasty (referring to the Pitch, not tone nasty).
I notice that if I switch the Harmony option from +2 to +3, the harmony seems to shift up a half step, but it still sounds nasty

Any advice/help is appreciated

Note: I did google this before writing this thread, but found nothing other than ads and reviews of another Harmonizer (physical), nothing about how to use one.
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The harmony you get will depend on 1. the key you choose and 2. the note note created based on the interval you choose. If you are play in C and you want to do a simple harmony put the "Harmony" knob on +3 and when you play C you will get a note E (the 3rd note of a C major scale). 
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Serious question. Is your guitar in tune? Not relative to itself, but actually in tune. I have used harmonizers that glitch if you are like 30 cents off and can't decide which note you ate playing and therefore can't decide which harmony note to play so the harmony is wonky.

But like dspellman said, actually reading the manual can be very enlightening on complex pedals and they often give you suggested settings that may be very useful or complete garbage.
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