![]() ![]() Each output can also have its own waveform (square, triangle or sine–and you can skew the triangle into a saw). Octature), or you could have 4 sync'd LFOs, running at different rates (1x, 2x, 4x, 8x) each with their o° and 90° outputs. You could have 8 phase shifted outputs running at the same speed (like a Dr. Each of the outputs can also run at a different rate division/multiplication. You can configure each of the outputs to have a specific phase offset (within a range of 1-100%). If you want maximum configurability, this is the module you want. ALM Busy Circuits Pamela's New/Pro Workout I will often plug three of its outputs directly into my Color Chords to get a looping, shifting color field–something that is surprisingly difficult to achieve without a module like this. In practice, this makes working with RGB signals really, really nice. It also, interestingly, has phase shifts of 120°. It outputs at 0-1V (other modules listed here will need some attenuation). This is one of the few modules with this feature set designed specifically for video use. Video Headroom Systems Baja/Bajascillator In LFO mode, the different filter outputs are 8(!) separate sine LFOs with a phase offset of 45°. While designed as an audio filter, it can also self-oscillate in both a VCO and LFO mode. ![]() This one's discontinued, but shows up on the used market every so often. The LFO rate is also controllable via CV, but that's harder to pull off well in practice. You get really clean sine modulation, four outputs, and three speed ranges to choose from. It makes its way into nearly every patch I make. In the modular realm, you'll most readily find this capability in so-called quadrature LFOs. An easy way to accomplish this is with phase-offset LFOs running at the same rate, like so: When the first tone reaches its peak pitch, the next tone is still rising, taking the lead when the first tone resets and begins its rise again. To create a constantly rising tone, what you actually need are at least two tones that are offset from each other. Neat, huh? Modules Neededīefore we get into specific modules to accomplish this, let's talk about the theory behind a Shepard tone. It creates a constantly evolving image that never quite runs the risk of clashing modulations, while at the same time establishing a baseline loop that the viewer can latch on to. This is where a visual Shepard tone comes in. I lean towards creating patches that play themselves. It's hard to control for unless you are riding the knobs the entire time. Sometimes you end up with clashing modulations that result in images that don't quite work. Add a few more modulations at different rates and you've got a much more complex, evolving patch. ![]() In music terms, this would be similar to techniques used in drone or minimalism. A shape may be ping-ponging across the screen, but if there is another slower LFO shifting the color, the loop isn't quite the same. One way to hold viewer interest is to overlay modulation at differing rates. After a few cycles they get the idea and want to move on. This can be nice, but it also creates a very noticable loop point for the viewer. In very simple patches, a triangle wave LFO used as a modulator creates a kind of ping-ponging effect. I see it as a form of repetition, but one that also tricks the brain into leading the viewer forward. Notice how it just seems to keep going up forever? That's what I am after in my video work. One thing they point out in the video is that a visual equivalent would be a barber pole: Ring any bells? If not, Vox did a really good explainer with examples in popular media. A Shepard tone is an audio illusion where a pitch seems to be increasing (or decreasing) forever. One of my favorite video art techniques is to create a visual Shepard tone. ![]()
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