Video #2: DSI Sequential Prophet-6 filter sweep demo jam: stepping? quantization? Harmonics! See description

Video #2:

DSI Sequential Prophet-6 filter sweep demo jam: stepping? quantization? Harmonics! See description 

https://www.youtube.com/watch?v=IrH2dlvDaeA

Diagram showing the harmonics / overtones series generated by a chord, much of which is easily audible with resonance high on the Prophet-6 filter:

Description for this second video:

"Prophet-6 filter demo jam. 

Compare Prophet-5 revision 2.0: https://www.youtube.com/watch?v=FKSMWd4U7AU.

Demonstrating the "stepping" in the P-6 filter resonance, which in my view is probably always related to harmonics / overtones of the notes being accentuated by the filter resonance at the cutoff frequency and not to quantization of the cutoff knob.

When I say quantizaion, I mean apparent quantization becausue I actually think now that it is all overtones sounding. THE FILTER IS JUST TOO GOOD!! It's most apparent when resonance is at 9-10, which is when the resonance is at its narrowest bandwidth (highest quality factor), which is where you would expect it.

This was a jam not a demo at first but I posted it because I had a lot fun making the thing and trying to get a handle on this Prophet-6 filter. So no complaints about camera work please - it's difficult to hold the camera, play the synth notes and tweak the controls with only two hands!

Features filter sweeps using cutoff knob, filter envelope amount know and low frequency oscillator, alone or in combination. No particular order.

To me, the question might become - why don't you hear this "stepping" effect so much on other synths?

I'm getting to like the sound of the Prophet-6 more and more.

At high frequencies, any overtones are so close together that I guess they merge and they are indistinguishable.

At mid frequencies (around 2-4 octaves above the note played), the harmonics are close together but are still distinguishable as notes. They almost follow the chromatic scale but some will be missing depending on how many notes you are playing and which notes they are. This is where the apparent stepping occurs. Careful listening reveals that there are gaps and the stepping is not quite chromatic.

At lower frequencies, 1-2 octaves above the note, you can clearly hear the 2nd, 3rd and 4th harmonics (1st, 2nd and 3rd overtones) separately.

2:54 With filter keyboard tracking OFF, HALF and FULL.

The effect is greater with filter keyboard tracking ON because each note will have a different filter cutoff frequency, lighting up more overtones.

So with keyboard tracking OFF, you get fewer harmonics because of this. I stopped mid-sentence when I was talking.

On any kind of high resonance filter sweep, as the cutoff frequency comes down on the down-sweep, the harmonics become more sparse and you get a deceleration effect as you get to the bottom of the cycle. This gives the effect of a sine wave type LFO wave, even though it's a triangle (apparently).

Also, since it is a polyphonic synth you can get more overtones than with a monosynth because you can play more notes at once. This is probably why people are noting this on effect polysynth like the P6 (they did on the P5 too).

To make the sweeps as smooth as possible, you probably need to do one or more of these things:

*play only one note at a time

*Have filter keyboard tracking OFF

*Use square waves on the oscillators (that don't have even harmonics, only odd) instead of saws (that have odd and even)

*avoid setting the cutoff in the region where the harmonics are almost chromatic

*set the resonance not above 9 or

*sweep really quickly

The overtones will probably also depend on which wave shape you use of course! Square waves don't have even harmonics, only odd ones but saw waves have odd and even (you can tell intuitively because of the skewed look or asymmetry of the saw shape).

I don't remember hearing that region of the harmonics so clearly on my old Revision 2.0 Prophet-5 with SSM filters. Instead, there was a kinf engine like pushing up sound as the resonance passed through the close spaced overtones and it was a little more vague and less obvious.

5:05+ growly harmonics and near 5:30 you can clearly hear the nearly chromatic part of the harmonic series.

At 6:28-6:50, I said there is some quantising sound on a filter sweep WITHOUT THE... I meant "without the cutoff knob being used" - only the LFO - but again it is just harmonics. You can hear that it is nearly chromatic but not quite. So I conclude that it is just overtones being lit by the resonant filter.

At 7:30-8:30 not a lot happens because I forgot what controls I had moved.

8:22+ and 9:20+ I get the run of almost chromatic notes followed by an arpeggio of the lower harmonics coming out.

At 9:20 you get several chords with arpeggios of harmonics - and again at 10:25+.

9:54 I particularly like this sound! Slow harmonics - leading to almost chromatic ones.

10:23+ I speed it up a bit and get better apreggios of harmonics.

11:45+ Slowing it down again, I get a favourite sound at the end.

Video file MVI 7410.

Keywords:

Sequential, Prophet-6, Prophet, filter, cutoff, harmonics, overtones, resonance, quality, quality factor, Q, keyboard, tracking, sweep, knob, low frequency oscillator, LFO, tone colour, tone color, Prophet-5, Dave Smith Instruments, Dave Smith, DSI,"