Oscillators - Newbie Question -

[shykedmi]

As it seems, i'm practically starting to finally get to know my vicious keyboard (Roland XP-60, who's now i realize is not as vicious as i thought, but it's an amazing workstation nevertheless!). I create sounds, modify them. That's the most important thing for me now.

But, i was always fascinated by the whole idea of Electronics and Music. I mean the whole issue of Oscillators, etc. I mean, a Digital Synth is the exact same thing as an Analog One, only that they work differently technically.

On my XP-60 i can move each patch through 2 Oscillators (LFO of course). For some reason, i noticed that the First Oscillator oscillates much more faster than the 2nd one.

I wanted to know, first of all, whats the thing with oscillators? Why do i need 2 of them? Can i theoretically take a sound a move it through more than 2 oscillators? Lets say, 64 oscillators? I know nothing about the subject - Just raising questions.

I noticed that i can also take (i assume that's the whole idea) one oscillator that will oscillates as a sawtooth, and one that will move as a triangle, etc. Is it best to try these experiments on a lead voice (such as a build up of a Moog for instance?).

And if someone can also give me some more explantaions about the options of Cutoff and Resonance (I know what the Decay and Attack do), i will be very thankful for him. I recognize in my ear what it does, but technically, i know nothing about what it do and why it does it.

Lots of questions, but i have to learn, right? Wanna catch up with you monsters. :)

Shy

[Luca_Capozzi]

seems you're referring to Low Frequency Oscillators that, usually, are used to constatly manipulate some paramenters.. as pitch variation (ex.: vibrato) or to let your LowPass Filter give a fat sound to your pad... Have you checked the various parameters of your LFOs? Check out their frequency for "speed" settings.

Also you can check Progsounds Board (http://www.albertorizzoschettino.com/%7Eprogsounds/board/), under Theory of Soundshaping.. i've linked some useful readings and there are other very useful posts made by users.

see ya

[Jerry]

Shy:

Nice post. I play an xp30 and an XP50 from time to time. They are great synths. Here's some advice for you.

As it seems, i'm practically starting to finally get to know my vicious keyboard (Roland XP-60, who's now i realize is not as vicious as i thought, but it's an amazing workstation nevertheless!). I create sounds, modify them. That's the most important thing for me now.


Modifying sounds is a great way to learn how to create them. 8)

As you move around parts of the architecture it will be helpful to keep some kind of map in your head. The basic XP architecture is like this:

(1)Wave => (2) Filter => (3) Amplifier => (4)Effects =>

(5) LFO's (6) Envelopes

This is the typical synth architecture. Notice that LFO's and Envelopes are off to a side. The sound does not move through LFO's or envelopes. LFOS/Envelopes are modulators, which is to say they vary the sound over time, depending on how you engage them. Most commonly LFOs' and envelopes are applied to three points in the architecture: Wave Pitch (for vibrato), Filter cutoff (for wahs and pitch sweeps) and Amplifier (for tremolo or fade-in effects, etc.)


On my XP-60 i can move each patch through 2 Oscillators (LFO of course). For some reason, i noticed that the First Oscillator oscillates much more faster than the 2nd one.

I wanted to know, first of all, whats the thing with oscillators? Why do i need 2 of them? Can i theoretically take a sound a move it through more than 2 oscillators? Lets say, 64 oscillators? I know nothing about the subject - Just raising questions.


There are two LFO's (low frequency oscillators) provided in the XP architecture. You can set them to different speeds and shapes. LFO's can be used to modulate pitch in which caes one often sets them pretty fast. Sometimes you use an LFO to drift/vary the timbre over time, in which case you might set it slow. It depends on the patch.

BTW, not all oscillators are LFO's. Some are high frequency ones (or audio rate oscillators) which typically generate sounds. In the xp these osccilators are replaced by the waveforms, which can be recordings of audio rate oscillators (like the B46 sine, b26 moogsaw, etc.) . Or of course they can be recording of natural instruments (e.g. A51: pipe organ)


I noticed that i can also take (i assume that's the whole idea) one oscillator that will oscillates as a sawtooth, and one that will move as a triangle, etc. Is it best to try these experiments on a lead voice (such as a build up of a Moog for instance?).


Yes. Use ceteris paribus as your technique, just like any scientist. Keep everything else the same, and change one thing to see what happens. Note that some parameters are dependant on others, so there are times you need to play with 2-3 variables at the same time to gain a full understanding.

And if someone can also give me some more explantaions about the options of Cutoff and Resonance (I know what the Decay and Attack do), i will be very thankful for him. I recognize in my ear what it does, but technically, i know nothing about what it do and why it does it.

You are going to have to educate yourself. Go to this link and try out the "Synth Secrets" links. The answers to your question are in articles 4 and 5. :P

http://users.pandora.be/tenor/index.htm

But briefly, a filter cuts some portion of the sound out. A low pass filter cuts off the higher frequencies. The point at which it cuts off the frequencies can be varied by you. This is the cutoff point. You can also amplify the frequencies around the cutoff point using the resonance parameter. If you crank the resonance to high and sweep the cutoff downward, you get the prototypical filter sweep (Tcheeeoooooo) sound.

Hope this helps,

Jerry

[maJ estY]

Great post, thanks Jerry! ;)

Sincerely,
a XP-30 user :)