Well there is also a vibrato effect and a little bit of chorus.
70% is the filtering.
Dont forget the original analog synths were all based on Subtractive Synthesis.
Start with a wave full of harmonics and then filter that down to produce other wave forms.
The theory works great on guitar.

Plus if you start with a distorted guitar you have TONS of harmonics and a very rich wave form to work with.
Case in point is the Electro-Harmonix Micro Synth.
Good luck.
Bill Ruppert

Thanks Guys!

Julian.
When I first sat down to make the flute sound I grabbed the HOG, as I thought the Spectral Gate would be a big help in the sound.
In the end I used the POG as its filter section did just what I needed and fast.
A Flute sound is a Sine wave which is a wave that has the upper harmonics rolled off.
The POG filter in the second position did the trick.
A simple flute sound is constructed basically of just the fundamental note.
In other words its just the original note with out any octave sliders added.
The dry signal path with the filter slider (filter switch 2) turned down made it work.
Before the POG I used a Graphic Fuzz with a very small amount of Dist and a EQ curve of an upside down smile. I other words 1000Hz was pushed up and the other sliders around it lowered.
This Pre-EQ helped the POG by boosting that fundamental note and rolling off the upper and low frequencies.

I can not see why you could not get something close using the HOG.
I hope this helps a little.

I will have some new fun sounds coming up using the HOG.
Bill Ruppert

Wait… I will work on it.
I have done it before:-)

Bill Ruppert