Acid Synth Modulation?

[Meteo Xavier]

As I dive deeper into properly learning electronic/beat driven music, one thing I'd love to learn how to do is be able to do that crazy acid synth lead riff that I hear in so many old breakbeat tracks.

This Crystal Method track has probably the best example I can come up with what I want to learn to do:

, between 2:11 and 2:41.

What is it you automate to make it do crazy FX sounding stuff like that? Seems like something's going on in there but I don't have the production cred to figure it out.

Thank you!

[lazygecko]

That's just a bandpass filter with cutoff and resonance changes.

[zircon]

Yep; it's also not the traditional acid sound that you often hear. The squelchy, rezzy acid synth comes from an old Roland unit called the TB-303. It's famous for it's filter resonance which is unlike most other analog synths. Of course, many VSTs emulate it, such as Audiorealism Bassline. Synth1 is pretty good for Crystal Method-style acid stuff overall, given that TCM uses Nord Leads extensively, and Synth1 is loosely based on that synth. I suppose what makes the synth line unique is that they're changing the filter cutoff with each note as opposed to doing a smooth line or curve.

[Yoozer]

But the 303 only has a lowpass filter, not a bandpass filter, and this is clearly a bandpass as Gecko mentioned

You're right about the cutoff changing per note - it repeats, which suggests a pattern instead of S&H (or a very naive S&H). That means that either the synth has a step sequencer or that the cutoff modulation is automated - and there are a variety of ways for that. Since we're talking about 1997 here it could be the Nord Lead (the first version was from 1995) - and then it's simply a matter of moving the modwheel and linking that to the cutoff.

[lazygecko]

I suppose what makes the synth line unique is that they're changing the filter cutoff with each note as opposed to doing a smooth line or curve.

This is easily replicated in Synth1 by making a filter LFO and picking the random waveform, then have it retrigger on every key. Alternatively if you need more control you just tie the filter to velocity.

[zircon]

But the 303 only has a lowpass filter, not a bandpass filter, and this is clearly a bandpass as Gecko mentioned

You're right about the cutoff changing per note - it repeats, which suggests a pattern instead of S&H (or a very naive S&H). That means that either the synth has a step sequencer or that the cutoff modulation is automated - and there are a variety of ways for that. Since we're talking about 1997 here it could be the Nord Lead (the first version was from 1995) - and then it's simply a matter of moving the modwheel and linking that to the cutoff.

Yea sorry, I meant that the traditional rezzy/squelchy sound is from a 303, not the sound in the TCM song. I would definitely guess Nord Lead as it's one of their favorite synths.