Ambient Arpeggios using LFOs and a Quantizer

One of the coolest things about Eurorack is that there are tons of neat tricks you can wire up with your modules, to produce some really cool sounds. 

A common trick, one that I recently came across, is the idea of using a LFO (low frequency oscillator) with a quantizer to produce an arpeggio. 

How exactly does this work? It's all in the quantizer, which takes incoming voltages from the LFO and adjusts them such that they match the voltage of a note that belongs to a scale (in accordance with the 1V/Oct Eurorack standard). That's why the outputted voltages (notes of the arpeggio) sound melodic, when connected to a voice. 

Here is a quick graph (not my graph) which should help visualize the concept of quantization.

As you can see, the blue line is the result of quantization; a discrete set of voltages, whereas the red line represents a LFO sine wave.

I decided to try out this trick by using Tides to generate some LFOs, 2HP Tune to quantize the notes and Rings to act as the voice. Here's the result:

Wow, Rings really does make some mystical sounds when you send an arpeggio into it, like the twinkling of a star! I love how melodic it sounds and the relaxing mood it puts you in.

Now let's break down this patch into a bit more detail. As I said, I've set up Tides to generate some LFOs. To do this, I've set the frequency range to 2Hz (yellow), the ramp mode to cyclic bipolar oscillations (red) and the output mode to different frequencies (red). That means that each output is producing a LFO of different frequency. Pamela's Workout is also clocking Tides.

The first Tides output is sent to Shades, to set the range of voltages. It is then sent to the Disting MkII, in full-wave rectifier mode, which takes the absolute value of the voltages (i.e. removes negative voltages). From here is goes through 2HP Tune, which quantizes the voltages to a melodic scale. As I mentioned above, this quantization creates the arpeggio of notes.

Rings is the voice of this patch. In particular, it's set to the quadriophonic (red) alternate "Karplusverb" reverb mode (flashing red) and receives the arpegggio sequence from Tune. This mode, I've found, is great for generating ambient-like sounds, mainly because of the reverb it creates. 

The other outputs of Tides are used for CV modulation, the second output modulating Rings' frequency setting and the third output modulating Rings' position setting. This adds a bit of dynamics to the patch, so it doesn't always sound the same.

The Doepfer LFO provides even more CV modulation, modifying the Tides' slope and frequency settings (this is what speeds up and slows down the rate of the arpeggio) as well as the brightness setting of Rings.

And finally, to add some randomness to the patch, 2HP TM generates a random voltage to set the bias of Tune. This modifies the base pitch of the arpeggio.

And that's pretty much it. It may sound a bit complex but the core idea of this patch, again, is passing a LFO through a quantizer to create the arpeggio of notes. Such a neat idea this is!

Have you tried out this trick? How did it sound for you? Let me know in the comments!

Happy patching friends,

-Uncle Peter

Sequencing with Pamela's Workout

Pamela's Workout was one of the first modules that I added to my rack.

From the start, I knew it was a powerful module that had a variety of features (kudos to ALM for that). In my videos, you've mostly seen it as the clock source for my patches and I must say it does a very good job at that!

A couple of days ago, I was going through the user manual of Pam's Workout and found a small paragraph saying that the module could also be used as a sequencer. For those who do not know, a sequencer is a module that generates a sequence of notes, with defined lengths and pitches.

I decided to give it a try and create a four beat sequence. Here's how I did it:

1) Set four trigger outputs to /4 (division of 4)

2) For each trigger output, press and hold to bring up the "advanced settings"

3) Scroll to the "n" setting. This changes the "length" of the trigger (essentially turning it into a gate). Setting the value to n = 50 represents an eighth note and N=1 represents a quarter note and so on.

4) Scroll to the "r" setting, which sets the order of the sequence by offsetting the triggers. For my output 4 -> 3 -> 2-> 1 sequence, I used the following settings:

Output 1  -->  r = 1 (Gate)

Output 2  -->  r = 2 (Gate)

Output 3  -->  r = 3 (Gate)

Output 4  -->  r = 0 (Trigger)

Not too bad! A pretty melodic yet mellow sequence. You can definitely hear which notes are eighth notes and which are quarters. 

Let's get into the details the patch:

Since I didn't have a four-channel mixer, I had to get a bit creative. I send the first three outputs of Pam's Workout (which are producing gates/voltages now) to Mutable Instruments Shades, which is in attenuverter mode. This allows me to adjust the pitch of the notes via the knobs of Shades and mix the three inputs to a single output. This output is sent to 2HP Tune to be quantized to a scale.

The fourth output of Pam's Workout is actually a trigger, the start of the sequence, which I send to 2HP TM to generate a random voltage. This voltage is sent to change the bias of Tune, which offsets the scale, essentially changing the pitch of the other three notes, randomly, but still following the sequence. You can think of it as randomly setting the root note of the sequence. 

Finally, Tune sends the quantized voltages to Mutable Instruments Rings. Some CV modulation from the Doepfer LFO adds some depth to the sounds as well. 

And that's it! This was a pretty fun patch to build and it's always interesting to try out unorthodox ways of using modules.

Have you ever sequenced with Pam's workout? Want more details about the patch? Let me know in the comments below.

Happy patching friends,

-Uncle Peter