Harman DigiTech FREQOUT Owner's Manual page 6

USING THE HARMONIC TYPES
The Harmonic Feedback Types
The first five Harmonic Feedback types let you get feedback
at a predictable, repeatable frequency. Feedback is selectable
at a sub-octave, 1st, 2nd, 3rd, or 5th harmonic, where
harmonic is defined as a multiple of your note¹s frequency.
For example, the 5th harmonic is 5x your note¹s frequency
(which is actually 2 octaves above a major third interval of
the original note).
The Natural Feedback Types
The two Natural Feedback types (NAT LOW and NAT HI)
act more like natural feedback does. Using these feedback
types, you might get different feedback every time you play
the same note.
Here are some tips to steer the feedback to what you want
when using the Natural Feedback types:
• Getting Lower-Frequency Feedback
Try playing more softly, rolling off your tone, and using the
neck pickup.
• Getting Higher-Frequency Feedback
Try picking your notes harder, opening up the tone control,
and using the bridge pickup.
• Getting Transitioning Feedback
In general, high-frequency feedback is more likely to transition to lower frequencies as the note decays.
Follow the instructions above for getting higher-frequency feedback to get more feedback transitions.
NAT LOW vs. NAT HI
Both feedback types have similar behaviors, but NAT LOW restricts the feedback frequencies to a lower
range and doesn¹t allow feedback at the 5th harmonic or higher. This restriction ensures that you don¹t
get feedback that sounds "major" on minor chords. NAT HI lets the feedback get a little higher-pitched,
and thus slightly increases the odds of the feedback transitioning mid-note.
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