A pitch-based reading of a FDD

25.11.2020 - Composition Techniques / FloppyDisk / Music / PhD / Words

As part of my current PhD studies I’m working towards developing new compositional techniques through the repurposing of redundant electronic music technologies. I’ve posted about my latest work turning a Floppy Disc Drive (FDD) into an audio sampler. This ongoing project will have more updates soon but in the meantime I’d like to share a few thoughts that are inspired by that project. This post is about a ‘pitched based reading’ of a FDD’s mechanism. I should mention that one exciting aspect of my PhD research is the integration of my electronic practice (circuit bending and device making) alongside my notated compositional practice; the former is based around a live performance practice. I’m interested in finding ways to use my handbuilt instruments not only for performance and recording but as tools for composition, whether conceptually or physically.

If you haven’t read my post The Floppy Disk Drive and the Phonogene, I suggest doing that first, as I explain how a FDD mechanism works and how I have approached recording audio with it. The main points to take away from that post are the use of 80 concentric tracks, the use of a read/write head and its ability to step forwards or backwards through the 80 tracks and the fact that the disk only spins in one direction, regardless of the read/write head’s direction.

So let’s dive in. In this ‘pitch based reading’ I’m taking the above elements, (concentric tracks, reading direction and fixed rotation direction) and using them as a basis for the manipulation of a set of pitches, with or without rhythms attached. I am conceptually ‘writing’ notes to concentric tracks and reading them back in forwards and reverse.

C major scale. The brackets indicate the track they are written to.

Let’s write two notes (show to the left) to a track. Out of our scale we have 4 tracks; a forward direction connects them as 1,2,3 and 4 and the reverse 4, 3, 2 and 1.

Now, what I discovered when working on my FDD audio sampler was that when you connect the concentric tracks in a reverse direction they are still played ‘forward’ due to the fixed rotation direction of the disc, and therefore our tracks will always play in the same direction. This is what sparked the idea around this post. So if we read our 4 tracks in a reverse sequence we get this:

Reading tracks: 4, 3, 2, and 1

Each track reads the same, regardless of which direction the we ‘read’ it. With something more complex than a C major scale and different note groupings you could make some interesting patterns but you can also do this by reading each track out of sequence: the alternate track groupings below shows this. I should point out now that achieving this with my actual FDD sampler should be possible, but at this stage this is a conceptual process since the sampler is still a work in progress. I do aim to realise this with it once I’ve progressed the project.

To skip forward a little, lets see what happens when you take the tune ‘Mary Had a Little Lamb’ and assign it tracks based on note groupings. Here we will have pitches and rhythms, which will undergo the same treatment as above.

Above we have three groupings. One is a grouping by bar (four beats) and groupings of three and two, indicated by brackets, which are grouped by articulated note, not duration like the bar groupings. I chose this latter method of grouping to achieve a more interesting result.

First up, lets assign each bar a track. There are 8 bars so 8 tracks. If we read the tracks sequentially in a reverse direction we get this:

Now let’s take the three and two note groupings, or articulation groupings, and do the same:

In essence we have a set of variations upon ‘Mary Had a Little Lamb’ which will always start from a G semibreve. Listening to the examples above, I was surprised at just how effective the two note grouping was at creating interesting pitch and rhythmic sequences, especially when some miniums are held across a bar. This concept can be expanded on a much larger scale, but for now this shows the basic concept that I’m using and although I’ve presented this ‘pitch based reading’ of a FDD in a rather basic way, I’ve been exploring other ways of taking this concept and applying it to other compositional parameters and processes through compositional sketches, which I hope to share in subsequent posts.

A few closing thoughts on where this is going. I’ve only really scratched the surface of how this FDD concept can be used within a compositional framework. I should acknowledge that it bears a close resemblance to serial techniques, especially the use of retrograde (reverse) sequences but should say that I’m not interested in going down that route. I’m intrigued to see what can happen to pitch and rhythmic material when adding a two extra parameters: disc rotation direction and disc speed. However, even with the parameters used above, the more complex the musical material, the more varied the output. In my own work I can see the use of this technique to create pitch fields and melodic sequences through more complex combinations of tracks and read direction: forwards or reverse, sequentially, alternatively and at random. If it is applied to rhythm and pitch separately, such a dissociation could further generate more varied results when the two are combined together (on the page). On a larger scale, if this concept was applied to musical structure, on a variety of levels — short, medium or long time scales, for instance — then a variety of structural possibilities, separate from pitch and/or rhythm, could take place.

More to come!

› tags: Analysis / Composition / Floppy Disk / Mechanism / PhD / Techniques /

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