Old monophonic synthesizers have had all sorts of ways to sequence notes; from fairly complex programmable sequencers to simple arpeggiation. Arpeggiators are nice because they sequence the notes that are played on the keyboard in realtime, allowing the performer to improvise while taking advantage of the capabilities of the machine at the same time. Based on the speed of the LFO, the arpeggiator on the Sequential Circuits Pro-One will sequence all the notes in a chord in either ascending order, descending order, or both. Other synths offer a feature to play the notes in a random sequence. In this example the notes are played in ascending order. I cranked up the LFO and added some delay so that the notes blend into each other so you can hear the harmony in the sequence. With this technique you can sort of simulate polyphony on a mono-synth.
Analog Arpeggiation
To make this 4:15 minutes long recording I found a creaky spot on the wooden floors of my house, rocked back and forth in place and pointed a stereo mic at my feet. I remember doing this years ago, but thought I’d give it another go using a faster sampling rate and bit depth so the quality is not reduced as much when pitched down. Before making the recording I set the sampling rate and bit depth to 96kHz and 24 bit. I pitched it down two octaves and then normalized the results before rendering the final output. 
I have yet to use this recording for anything. I made it about a year ago when I was working on the sound design for a 3D animated short. It was one of many sounds that didn’t make the cut, but still has an interesting characteristic or two. We’re all familiar with the sheet metal wobble. The plastic mat wobble is similar, but with less racket and a sort of low frequency rubbery quality. I must have been holding my breath during the recording because you can hear me breathe in deeply at the end.
Here’s another sound that I would label as “Pro-One Dub”. I guess all that really means is knob turning and delay, but when you get good results with this instrument you know it. I love the fact that you cannot store presets on old analog gear. It makes you create a new sound every time you turn it on. I had the knobs in a pretty good position to start this time, but after a few more adjustments I got this great modulated effect with the LFO near top speed and at maximum amount. Just tapping a key gave me this nice squirty raygun effect, so I dropped that in the track before getting my sound for the melodic line I needed for the piece. Here’s a chunk of it pitched down a bit and running through a short delay with lots of feedback to create a vintage raygun effect.
This recording was made with a Shure VP88 stereo condenser mic on a Fostex FR-2LE field recorder as I was leaving work this evening. I usually exit out of a back stairwell with cement steps and brick walls. In other words, loads of natural sound reverberation.