ARP2600 - Any Tutorials?

[whyterabbyt]

What Justin said.

Also, if you want to modulate something patch to its control inputs, not its audio inputs.

[ghostwhistler]

if i route an lfo shape into the audio signal of the VCF for the oscillator I currently have running, why doesn't it modulate the amplitude of that vco?

Because, if that's your entire patch then

you're filtering the LFO as though it were an audio signal
and
VCFs dont necessarily affect amplitude, they affect timbre
and
there's no modulation being applied to anything
and
You havent got a VCO connected

Ok, let me see if I understand.

You aresaying that it's not working because I'm replacing the signal from the oscillator with the LFO signal?

well actually I was saying that it probably wasnt working for several reasons, and that there were quite a few things that werent 100% explicit enough to be sure as to which ones were most applicable. The filter has multiple inputs, and each input has a fader. You made no mention of which input was being used, or attenuation.

However you don't modulate something by connecting to its audio input. And if you wanted to modulate volume, you wouldnt normally modulate the filter.

I thought the VCO was normalised and all you had to do (assuming no further modifications) was turn up the fader in the VCF section. So the LFO cable has replaced that path?

Well, you didnt mention increasing the fader, and yes, if you connect an LFO to one of the connections normally normalised to a VCO, you're replacing that VCO signal into the VCF with the LFO as an audio signal.

I don't see how you can do that then. I'm talking about a simple patch where the only modulation is a tremolo effect, hence the waveform from the LFO being used. If I plug it into the Gate In on the EG i get a continuous tone instead of a regular tone that follows the ADSR. If i plug it in anywhere else nothing happens. Surely the LFO is required for this effect?

[cthonophonic]

If you want to modulate amplitude, the easiest way is just to use a VCA. Patch your modulator into a control input and turn up the slider to hear the effect.

[justin3am]

If you want a tremolo effect, you can either use the Ring Mod (set to DC for slow modulations) or one of the Control inputs on the VCA.

In the patch I described previously, set VCO2 to LFO mode and you will hear that VCO 2 controls the volume of VCO1.

[Shabdahbriah]

Some great advise thus far... here's some fun stuff with the CA2600, starting @12:15

https://youtu.be/c8qrt4C9kmQ?t=737

[whyterabbyt]

I don't see how you can do that then. I'm talking about a simple patch where the only modulation is a tremolo effect, hence the waveform from the LFO being used.

Yeah, and tremelo is amplitude modulation. You were plugging the LFO in as an audio input to the filter.
That's two major issues:

Firstly, you dont do amplitude changes with a filter, you should be using an amplifier, eg the VCA
Secondly, your LFO needs to control the amplitude, not be an input, you should have connected it to a control for the VCA

If i plug it in anywhere else nothing happens. Surely the LFO is required for this effect?

Yes, and you'd use it to control the VCA somehow, not input it as audio into the VCF.

You said you understood the basics of subtractive synthesis, but you're confusing control signals with audio signals and VCAs with VCFs, so I think you may not really understand as much as you think, which is why you're confusing yourself.

There are multiple ways to do this, depending on what you want to achieve.

If you want continuous tremelo even when there's no key down, connect the LFO output instead of the normalled AR connection on the VCA.

If you're want to use an LFO to drive an envelope, use it to trigger the AR's gate. The AR already modulates the VCA.

or to be clever, ringmod (ie multiply) the LFO and the ADSR and drive the VCA from the ringmod output.

or alternately, VCO2 is already set up to ring-modulate VCO1, so you could set VCO2 to low frequencies, disconnect VCO2 from the keyboard, and drop the faders to zero on everything going into the VCF except the ring modulator input. ( Or patch the LFO into the ringmod instead of VCO2)

etc.

But what you need to do is send a modulator into a control input for an amplifier, which is either going to be the VCA for very straightforward subtractive, or the ringmod for being slightly clever about it.

[dumbledog]

I don't know if it's already but I really recommend going through this patch book: Arp 2600 Patch book. This is the first thing I did when I got my 2600.

Whoa, I hadn't seen this one. Thanks for the link.

[whyterabbyt]

So, OP, have you got any further?

[ghostwhistler]

So, OP, have you got any further?

I think I have the basics of the oscillators and the filter and perhaps the vca. Not sure how the ring mod operates: there are two attenuators, one for vco1/2. But adjusting either doesn't seem to demonstrate an intuitive relationship to the listed vco. So i can turn vco1's attenuators down and still hear the effects of parameter change from vco in if vco 2's slider is full.

Also i'm not clear on how the envelope follower or the keyboard control works. I understand how to get something duophonic and waht last/high/low means. But the parameters above I'm unsure.

I'm trying to learn the voltage processor section right now.

Unfortuantely cherry audio's accompanying online explanations don't cover the envelope controls nor the ring mod operations i've mentioned.

Also the differneces in layout between this and the original/arturia version (from that guy's youtube clips) are a bit of a stumbling block.

[whyterabbyt]

A ring modulator will basically multiply one signal by another. If you multiple one signal by another, you're basically modulating its amplitude.



If you modulate the amplitude of an oscillator directly (as per Justin's method) you'd basically get this.

My RM suggestion was to multiply the LFO by the envelope, and use that to drive the VCA; that -might- be a little bit clearer to follow.

On the 2600 you've got gain attenuators on the two inputs to the RM. Use them to control the effective depth of the amplitude modulation.

Also, by default, the output of the RM gets fed into the VCF. For Justin's suggestion, you want to raise the gain on the attenuator for that, and shut down the gain on the VCO inputs, so what you filter is the gain-modulated audio.

For my method, you want it the other way round; none of the output of the RM goes into the VCF, instead, feed in the oscillators. Patch the output of the RM into a control input for the VCA.

[ghostwhistler]

A ring modulator will basically multiply one signal by another. If you multiple one signal by another, you're basically modulating its amplitude.



If you modulate the amplitude of an oscillator directly (as per Justin's method) you'd basically get this.

My RM suggestion was to multiply the LFO by the envelope, and use that to drive the VCA; that -might- be a little bit clearer to follow.

On the 2600 you've got gain attenuators on the two inputs to the RM. Use them to control the effective depth of the amplitude modulation.

Also, by default, the output of the RM gets fed into the VCF. For Justin's suggestion, you want to raise the gain on the attenuator for that, and shut down the gain on the VCO inputs, so what you filter is the gain-modulated audio.

For my method, you want it the other way round; none of the output of the RM goes into the VCF, instead, feed in the oscillators. Patch the output of the RM into a control input for the VCA.

Forgive me, but it's not what a ring mod is that's my issue, it's how to use it on this synth.

[Ah_Dziz]

The ring mod has two attenuated inputs (osc 1+2 by default), one output and a normaled connection to the vcf if I remember correctly. The two signals in will be multiplied and the depth of that modulation is set with the input levels. You can run whatever you want into the ring mod and at the output you will have the sum and difference frequencies of the inputs. I don't know off the top of my head if the 2600 does proper balanced modulation or not but the difference would be negligible in many cases. So if you want to use the ring mod, plug two signals into input one and input 2 and then turn up the ring mod's audio input in the vcf. It isn't very different from other synths especially if you are using the standard normaled connections.

[Shabdahbriah]

This thread is actually encouraging me to pick this up, sooner... (way-to-go)

[whyterabbyt]

Forgive me, but it's not what a ring mod is that's my issue, it's how to use it on this synth.

well, ive gone into some detail as to how to use the ring mod on this synth to get the tremelo effect you said you were after.

[Ah_Dziz]

Also, the ring mod on this synth works like pretty much every ring mod everywhere. You just have the ability to patch alternate sources into it. I would recommend using it with zero patch cords until you can use it like a normal synth. Then start patching around. Also maybe do some research on audio, control and gate signals and how they are commonly used as well as situations where one might replace another (fm, filter fm, driving envelopes with LFOs, and other standard modular techniques). Once you can use the thing without patch cords then you'll hopefully understand the signal path enough to understand what happens when you replace a signal with a different signal via patching.