Module request: 16-step OSC

[wavemechanic]

So... I've been trying hard to turn step sequencers into oscillators. It recently occurred to me that my manmade waveforms were single-octave slivers of the entire voltage range and were therefore very inefficient, adding a ton of DC offset.

Out of all the step sequencers available to Voltage, only Benard's Multi Sequencer seemed to deliver the voltage control I was looking for in order to generate AC output from a step sequencer. So I instantiated the Cherry basic OSC and sent it to the external clock of Benard's Multi Sequencer. I thought the randomizing feature of the sequencer would also be pretty amazing. I could just randomize jagged waves of joy with almost no effort.

But alas... this sequencer revved up to audio rates was not pleased with me, particularly when I tried to invoke the second row and pan the two sequences to left and right. My machine started choking. During this time, the Oscilloscope would remain mostly blank, except for the occasional blip of a waveform. It painfully struggled to keep up but could not. When I stopped the DAW, a few seconds would go by while the entire VM GUI would lock up. After a few seconds of this, a train wreck of spaghetti-ed waveforms would crash out of the scope, and then things would finally be back to normal.

So I have given up on the idea of driving step sequencers at audio rates, leading to this post. Would some sweet dev out there make a not-so-bulky 16-step OSC that doesn't try to be more than an OSC? I'm imagining narrow faders that take precious little real estate, so we can picture the waveform (knobs make it hard to visualize); and add a randomizing button for the faders? Of course, it would need the usual trimmings like pitch, range, fine pitch, sync. This alone would be wonderful. Some options that could make it more fun are Phase Modulation and VC inputs for each step, to name a couple.

OK... I will now go pray at the altar of the synth gods.

PS: Oh, it also needs a slew. In my experiment, the pixilated square steps sounds pretty damn devastating (in a good way), but adding a bit of slew was a nice way to smooth the transitions. This doesn't really need to be built in, but it would be handy and probably add inspiration for users. Using Cherry's slew, 0.1 to 5% was pretty usable. Adding additional control over slew behavior itself (how it responds) could be extremely exciting.

[MRBarton]

You can make the waveforms AC by passing the sequence output through a high-pass filter tuned anywhere below the freqs you are generating. Pass that output through a low-pass to add the slew/smoothing you ask for. This is modular synthesis. You can usually build anything you want. My Lab Filter or the Oberfilter would be fine for these tasks.

[wavemechanic]

That's superb knowledge. But still the CPU load appears to be a problem, particularly with the 16-steppers. And now that I've given this enough thought to write a post, I think a dedicated OSC with these extras would be quite a bit better as well as much lighter on the CPU. Still, this is marvelous, and I'm going to try it. Thanks!

[wavemechanic]

MRBarton, I'm having an oh-duh moment. As a mastering engineer, I'm always high passing stuff for this reason. It never occurred to me to apply it in this context. Thanks for pointing that out! I kind of liked the sound of the slew. Felt slightly like tape.

[wavemechanic]

MRB,

I'll be damned. I tried it again tonight (using the same setup I had the previous night) and both the 8-step and 16-step from Cherry worked fine as an OSC. It doesn't have the CPU issues that the VC sequencer I tried had. In fact, I'm not currently hearing nor seeing the DC offset this time around. Regardless of that interesting observation, the Cherry Drum LP/HP module is a really good next stage after the SEQ OSC. The LP filter does do nice shaping of the waveform, and it's fun to play with both the glide and the filter. I still think it'd be sweet to have a dedicated step OSC with VC on each step and other bells and whistles related to OSCs as opposed to sequences, but I guess I could modulate this a hundred other ways. It also just occurred to me that I could hard-sync this StepOSC to another OSC by using the other OSC as the reset trigger. I know this is elementary for you, but I'm still getting the hang of modular imagination.

Thank you for your suggestions and pushing me to go back and try it again!

Cheers

[MRBarton]

By how you are describing your exploits, I can tell you're doing just fine. New ideas and methods will pour in fast and furious. What I love about VM is the way you can just soar with stream of consciousness ideas without being hampered with finding patch cords of the right lengths, or cursing because you don't have two of a certain module, or trying to get your fingers around those tiny Eurorack knobs while looking for your reading glasses to read the legends, or going broke.

[wavemechanic]

I concur. I am already getting a sense of that nearly infinite universe. It really is liberating. I also like to loop out through a class-A tube amp. So by the time it gets mixed, it truly is analog sans caveats. I embraced VM, because it is a DAW native plugin. I'm a song writer/producer and need that tight integration. But I'm getting pretty giddy within VM sound design at this point.

[ymerejsasnak]

Hi,

I stumbled across this conversation and thought I'd add in something. First of all, I'm a fan of experimenting with using things the "wrong" way, trying to turn any signal into some kind of audio (I also like ugly digital sounds in the right context!).

Second - and I always feel awkward plugging my own modules but here goes - JK's CV Canvas is more intended for drawing custom control-rate signals, but with its recent update you can put it in "phase mode" and use a saw/ramp-up oscillator as a phasor and use that to read freely drawn shapes. Of course, this module isn't specifically designed for this, so things like aliasing and interpolation noise could be concerns, but speaking of ugly digital noise, I've managed to get some really cool/interesting sounds out of this practice.

Just a thought. If it doesn't fit your needs, no worries.

JK

[Steve W]

JK's CV Canvas is more intended for drawing custom control-rate signals, but with its recent update you can put it in "phase mode" and use a saw/ramp-up oscillator as a phasor and use that to read freely drawn shapes.

I gotta try this. OK!!! I tried something; not sure its what you had in mind. Basically I have a simple Free-Hand Wave Shaper. Since it is really off-topic here, I will post an image in the module's thread.

[ColinP]

I've been experimenting with this idea too. Basically though you need a pure mathematical sawtooth to feed the sequencer. Standard oscillators include some anti-aliasing that paradoxically is undesirable here as it distorts the sequencer's timing. Also CA's basic oscillators seem to include features designed to make them sound perhaps a bit more organic and these make matters worse - introducing glitches and underrun.

You can get some nice yet nasty nasal sounds quite easily though.