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Modular Diary – 087

Richard D. James on tuning and drift in his interview with Tatsuya Takahashi:

RDJ: …I guess some people like their Osc’s drifty and others not so. It changes with the context I guess. Also, if you’re doing FM you might want to keep them dead on, and for analogue lead sounds, really drifty. Anyway I think I mentioned it before, but the drift on the monologue sounds REALLY nice. It seems to move, but then never go out… Sounds to me like it gets reset/synced at some point…

TT: That’s bang on! So same thing in the minilogue and the volcas too: the oscillators are re-tuned when they’re not being used.

Mark Boyd (biminiroad) has posted a few patches on the Audulus forum exploring different approaches to simulating oscillator drift and detuning. His Drifting Gateable Quantizer doesn’t drift so much as introduce small pitch deviations that can be dialed in post-quantizer to get a pseudo micro-detuning effect. Simple (and light on CPU) but effective.

His Drift VCO takes a more complex approach: When the oscillator frequency is below 1000Hz, an adjustable amount of FM feedback (also scaled by the pitch) is sent to the oscillator’s input, and since the lower frequencies have more feedback, they are also more out of tune. Above 1000Hz (roughly two octaves above middle C) a slow sine LFO modulates the pitch in order to avoid FM noise. I’ve been taking a look at the patch and wondering how best to introduce something similar – a reset when there’s a pause in activity.

It’s interesting that now that we have the possibility of perfectly tuned oscillators we yearn for the beauty of slight imperfections. Certain of Jerobeam Fenderson’s visualizations in his oscilloscope tutorial come to mind – the spinning (around 5 mins into the video) introduced by an overtone having a slightly imperfect ratio, for example.

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Modular Diary – 042

A little more on tuning systems: On the Audulus front STS has been doing some fine work on his o_C Scale Quantizer, and Jimbo refining his Microtonal Scale Modulater. I also updated my Detuner with some internal fixes and a reset input that takes all the LFOs back to their starting point.

I don’t have any of the modular gear needed to make use of it, but I found it interesting to see the multitude of ways for editing microtonal scales (cents, ratios, and fractions, as well as Hz values) that Spektro Audio have added to the latest version of their C.V. Toolkit.

Taking a look through my tuning bookmarks I also came across Todd Mudd’s delightful and thorough Just Intonation Toolkit. It’s great to compare how the different tuning systems feel.

And finally, some of the microtonal scales Aphex Twin created for the Korg Monologue.

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Modular Diary – 015

It seems to me that a large part of the increase in activity on the Audulus forum during the last half year has been due to recreations of hardware modules/instruments. The hardware models seem to provide a useful grounding – something to kick against in the open space of the software platform. In the absence of owning any hardware syths at the moment I’ve also found the fixity of app recreations – the Moog, Ripplemaker and VCS3 apps that I’ve looked at, a useful counterpart to the openess of instruments/devices created in Audulus. I do keep coming back to Audulus though – it still ends up being the place to get on with some real building after diving into the behaviour of the other apps.

A few weeks ago I had the Korg 2015 version of the ARP Odyssey under my fingers on a visit to a music shop, and now the Korg ODYSSEi also has it’s place on my iPad. While not exactly a modular synthesizer it has a wealth of routing options that make it extremely flexible, while at the same time practical to use as an instrument. GForce have created their own software version of it – the Oddity – and also provide a wonderful introduction to the original as part of their synth archive. As they mention in the video this can be a bit of an in-your-face punk instrument. The opposite of the distant spaciness of the (i)VCS3.

The iPad ODDYSEi sounds great, and especially with the white Rev. 1 face is a visual pleasure as well. The fader interface design1 (there are no knobs on this synth) seems well suited to an iPad touch-screen. I was delighted to find that the analogue tuning has been modelled as well. One can shift between pure equal temperament and the analogue version if it and clearly hear the differences. Richard D. James talks about layering similar differences between equal temperament and the analogue tuning of the Roland SH101 in his interview with Tatsuya Takahashi.


  1. With handy tooltips too. 

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Modular Diary – 013

A quick look at a few hardware sequencers that I’ve come across during the last few months:

Starting off with Mylar Melodies’ wonderful tour of the Intellijel Metropolis. (And Robert Syrett’s Audulus recreation of it.)

A step back to classic analogue sequencing (in a modern form) with the Doepfer MAQ16/3.

The Korg SQ-10, another classic given modern form as the Korg SQ-1 (here coupled with the Make Noise O-Coast).

Aphex Twin’s Cirklon.

And a step out of linear time with the Make Noise René.

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Modular Diary – 011

The arpeggiator of the Model 15 App is a step into getting an idea of how early analogue sequencers were set up: A voltage control knob for each step of the pattern. For pitch those voltages would typically be passed through a quantizer before being routed to an oscillator, but they might just as well be used to control velocity or filter cutoff, for example, perhaps with a parallel row for controlling gate times.1 It’s quite a different world from the piano roll visualizations one is accustomed to with DAWs, and encourages a different way of thinking – a different approach to creating and using sequences.

When I first started using Audulus I was somewhat puzzled by some of the sequencer modules included with it. I’ve since come to better understand (and appreciate) the old analogue models on which they are based. The great thing with Audulus is that all knobs can be linked to any other form of control – that means that the knob for each sequence step can potentially be controlled by an LFO or Random generator, to pick two examples. The sequencer can not only send out a set of control signals, but also be modulated itself.


  1. The Korg SQ-10 is a good example. Here’s a video with the SQ-10 controlling the MS-20 filters. 

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Modular Diary – 009

I’ve been thinking of how YouTube seems to have turned out as the channel for sharing modular stuff. Of course one important aspect (in the absence of being able to save patches) is being able to see the modules and how they’re patched together. Another is the many demonstrations of modular gear – almost small performances in themselves.1

Warp records recently published a wonderful (long) interview between Richard D. James (Aphex Twin) and Tatsuya Takahashi, one of the Korg engineers he worked with on the Korg Monologue. Amongst the many topics they cover is Richard’s fascination with synth demos:

I’m a secret nerd-fan of synth demos, mainly vintage ’80s ones currently! Some amazing music has been made as equipment demos, unsung heroes. I collect synth demos. Well, ones that I like. It’s kind of an unclassified music genre…

On can trace that fascination on a gradual scale from his Korg demo to last year’s Cheetah EP – focussed entirely on an obscure 90s synth of the same name.


  1. Mylar Melodies, for example. 

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