[sdiy] Silly vector synth question

[Gabriel Lindeborg]

Hi All!

In birth of the Prophet VS Chris Meyer writes:
"The first major change to the Diamond Patch (a name that curses Vector 
Synthesis to this day...it would be much easier to use if the four 
oscillator positions were the corners of a square instead, but Josh 
[Jeffe] felt the name demanded that the user interface arranged them 
like a diamond -which everyone has followed ever since) was to allow the 
four waves to be separately tunable."

The "Sequential Circuits Prophet VS Owners Manual" (page 6-5) goes on to 
say:
"To exploit the sonic power of four oscillators, Sequential engineers 
turned to the basic concepts of analytic geometry and found a very 
elegant solution in the Cartesian coordinate system. By assigning an 
oscillator to each of the four poles, a single point can simultaneously 
represent the mixture level for all four oscillators. For example, if 
the mixture point is exactly in the oenter (at the "origin"), you have 
an equal mixture of all four oscillators. Of course as the mixture point 
moves away from center, the oscillator(s) towards which it heads become 
louder and the oscillator(s) it moves away from get softer.
The basic way to move the oscillator mixer point is with the Waveform 
Mix joystick. Please see Figure 6-3 (next page). One dimension of the 
mixer (the "A-C axis"), is the blend of oscillators A and C, and the 
other dimension ("B-D axis") is the blend of oscillators B and D. 1'he 
mixer values for each oscillator are represented as percentages and 
always add up to l00%. So, when the joystick is centered, each 
oscillator level is 25% of the overall mix. One oscillator can have 100% 
of the mix."
And on the following page (6-6) four examples of stick position and mix 
result can be found.

Both documents are available at the web.

//Gabbe


Tom Wiltshire skrev 2011-02-06 12:15:
> On 6 Feb 2011, at 10:26, Gordon JC Pearce wrote:
>
>> On Sat, 2011-02-05 at 22:48 -0800, DTK wrote:
>>
>>> Its not so much about the proximity to center as it is the distance between
>>> the outlying point and the current stick position, if that makes sense.  If
>>> you think of it in terms of linear distance, when you move the stick to the
>>> far north position, you are (obviously) farther away from the south, but the
>>> distance to east and west also increases significantly as compared to the
>>> center position.
>> Ah! so if I have the values so that with the stick centred I get:
>>
>> N = 1, S = 1, W = 1, E = 1
>>
>> then when I move the stick north I should have:
>>
>> N = 0, S = 2, W = 1.4142, E = 1.4142
>>
>> because I'm calculating the hypotenuse of a triangle between the centre,
>> the stick position and the oscillator.  That makes more sense.
>>
>> Gordon MM0YEQ
> Does anyone know if the Prophet VS worked like this too? (Aaron? Don't you have a VS in your rack somewhere?)
>
> It seems like more sums than are really necessary, but I suppose it has the advantage of getting you closer to having just a single oscillator when the stick is pushed to an extreme. I should really have a play with this.
>
> T.
>
>
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