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LFO Slew Rate

LFO Slew Rate
« on: June 27, 2019, 02:13:18 AM »
Hey Guys,
Just got the Pro2, am in love with the overall sonic possibilities and the rare (although detuned) sound of the oscillators.
Right now im trying to replicate some of the patches i have on my op-1, which was my first synth/gear.
Thereon you can find a sinewave LFO, which im missing on the pro2.
Now does a slew rate of 128 make a triangle wave a sine wave? how exactly does the slew shape the LFO?
thanks in advance, hope its not too self-explanatory what im asking.
greetings
Alf

Shaw

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Re: LFO Slew Rate
« Reply #1 on: July 23, 2019, 08:00:00 PM »
Hey Guys,
Just got the Pro2, am in love with the overall sonic possibilities and the rare (although detuned) sound of the oscillators.
Right now im trying to replicate some of the patches i have on my op-1, which was my first synth/gear.
Thereon you can find a sinewave LFO, which im missing on the pro2.
Now does a slew rate of 128 make a triangle wave a sine wave? how exactly does the slew shape the LFO?
thanks in advance, hope its not too self-explanatory what im asking.
greetings
Alf


I don't currently have a Pro 2, but I would say use your ears.  I would guess (and if I remember correctly, it's an educated guess :/ ) that a slew rate of 128 would be too much, or at least more than necessary.  I think you can get a sine wave at less than 128 slew rate, but without squashing the range of your LFO like a 128 slew rate is likely to do.

If I'm wrong, hopefully someone will chime in and correct me.
"Classical musicians go to the conservatories, rockn roll musicians go to the garages." --- Frank Zappa

Re: LFO Slew Rate
« Reply #2 on: July 24, 2019, 03:25:32 AM »
I did experiment with osc2 as a perfect sine modulating osc1
and compared it with an Triangle LFO slew rate between 64-96.

OSC2 mod amount of 6 came close to LFO mod amount of 255 (LFO1 assigned twice to OSC1)

Whats quite noticeable is that even before the edges are taken of the triangle, the overall amplitude of the LFO lowers significantly by increasing the slew rate. It gets less edgy but also flater, thus reducing the audible modamount.
Whereas OSC2 as mod source produces rich harmonics in the lower and upper spectrum at only 6.
From 0-64 its still edgy compared to the sinus osc, from there on to 96 it feels much more round, but going further it just flatens out. So LFOSlewRate of 127 even with ModAmount of 255 is just adding little a presence but tonally nothing significant. So even altering the LFOShape isnt doing much anymore.


Im still wondering what the difference is between assigning osc to one another in the mod matrix and assigning them via the FM Amount in the osc page. The manual states there is no difference whereas audibly there is.