LFO sine 1 and 1/2 timing (ie emu sampler sine 1,2)

  • on teh emu theres a nice sine lfo shape that is one cycle and the second cycle is twice as fast as the first then back to one etc... Is there a way to achieve this in the virus?


  • I'm having trouble imagining it, so a drawing could help, but it sounds like FM is the answer here. OSC1 should be square and OSC2 sine, but only OSC2 should come out in the mix. Also the FM type should be wave, phase init should be something other than 0 (play around). Come to think of it, looks like the higher pitched sine might come first, but I don't think it should matter. OK then, you now need to balance the FM amount and the semitone of OSC2 (maybe even a little bit of detune), it could help if the FM controls were less coarse (Access people, if you can hear me!), but setting oscillator sync should at least give you a fixed point of reference so you are not completely lost.
    If you insist on having the low pitched sine first, a reverse-phase FM mode (meaning top becomes bottom for OSC1) could really help here... (Access people... ...again).

  • its an lfo, if you imagine an S (to represent the sine shape) with the bottom half of the S would be half the size of the top half, meaning it would oscilate at twice the speed.

  • Struggling with the Virus' limited (maybe even buggy) FM synthesis this is as close as I could get (start with init patch):
    Oscillator 2 wave select: Sine (pure)
    Oscillator 2 fine detune: 0
    Oscillator balance: +100.0% (only oscillator 2 is audible)
    Oscillator 2 FM mode: Triangle (not pos...!)
    Oscillator 2 FM amount: 22.7%
    Oscillator section initial phase (a.k.a phase init): 31
    As I have noticed in a lot of FM based patches, above C7 notes start behaving badly, especially if more than 4 or 5 keys are pressed - it sound more like Morse code transmissions - it would be nice to know if you get that as well...
    I tried to do it using the "wave" FM mode, but it doesn't seem to work as advertised...

  • I don't know if this is going to solve your problem, but have you considered modulating the LFO rate of a sine with another LFO, say a square?

    So say for arguments sake you want to modulate filter cut off, assign LFO 1 to the filter cut off, and make LFO 1 a sine wave, set LFO 2 to a square wave. If then in the mod matrix you set the mod source as LFO 2, and get it to control LFO 1 rate. What you should notice is that the modulation on the filter cut off will switch between two speeds, depending on the rate you set your LFOs at these speeds will be more or less noticeable. I'd personally recommend keeping the LFO speed of LFO 2 relatively slow. With some careful tweaking you might be able to get something similar to what you're explaining.

    It's important to not that assigning modulation an LFO rate of an LFO that is time sync'd will have no affect on the LFO's rate.

    I hope the above is clear and helpful to yourself!

  • *** Banging head against computer screen *** Arrrggghh! Why didn't I see it!?

    But, of course, whatever I said can be applied to 2 LFOs instead of 2 oscillators, like Lidge said - the key is the RELATIVE rate of the LFOs, the relation should stay the same when you want the effect to go faster or slower. Another thing is the contour of the square LFO which should be 67% since the positive side of the sine is twice as big as the negative side.

  • I just re read my post and noticed the second to last line made no sense what so ever so i'll try to re word what it was I was trying to say!

    It's important to note that assigning modulation to an LFO rate, of an LFO that is time sync'd, will have no affect on the LFO's rate what so ever. If you wish to modulate an LFOs rate make sure it's not time sync'd.