Week 7 - Class One

Now that we've ground our way through some 'composerly' processes for creating chord changes, we are going to use those concepts to create a sonic landscape for a gallery-like situations. As with the chord change process, this is going to use some basic rules-of-thumb to help us build an interesting - but semi-generative - bit of sonic art.

Although we did some work with changing keys, we are going to primarily focus on working within a single key. The core idea is that, since all of the notes will be part of a single key, any part of one track conceivably will work with any other section. Our job is to:

Creating Chord Changes that'll Work

The main thing you will want to do with your chord change selection is to determine how 'unsettled' you want it to sound. If you spend a lot of time on the I, IV and vi chords, the system will tend to sound quite stable. If you spend a lot more time on the ii, V or vii chords, the system will tend to sound very unstable - as if it was constantly 'on the move'. As chord tones move in and out of phase, you will find things too often sound discordant without resolving to a set of 'home tones'.


Note that I didn't say this was bad! This is where your artistic voice becomes important: you have to find the right chords and tones to match the location and work with which you are interacting! In many cases, a less settled soundscape is a much better fit for more aggressive companion art - more less bucolic locations.

Stretching Out the Changes

Once you have a set of chord changes, you need to make the composition happen. This means 'stretching out' the chords into long-form content, and reducing the number of elements that will play at any given time.

Probably the easiest way to do this is to work within the session view, but to use markers as notations for where chord changes occur. This way, you will be able to keep track of your chords even as you tear apart their inner structure.

Generally, when pulling things apart, you will want to over-emphasize the lowest notes while reducing the density of the high notes. Why would you do this? Our ear will notice - and become irritated by - patterns in the higher registers much more quickly than in the lower registers. Thus, you can have desirable repeated phrases in the bass line, but putting a similar phrase in the highest line will just bother the listener.

While pulling things apart, you will also want to pay attention to making variations - either grotesque or subtle - to the individual segments. I've found that adding effects (particularly delay/echo effects) and changing the amplitude and panning envelopes adds greatly to the sense of this being an interesting composition.

This is the part of the composition process that provides the most opportunity for creative voice and interesting decisions, so don't be shy!

Timing the Individual Tracks

In order to determine the time it will take for the entire composition to loop, we need to find the 'Least Common Multiple' of the track times for all of the tracks. On tool you can use is a web-based LCM calculator, like the one found here. Using this calculator, if we have three tracks times out to 2:30, 3:00 and 1:45 (which we calculate using 2.5, 3.0 and 1.75 minutes, respectively), we see that the system will repeat every 105 minutes. If you have more than three tracks, you can use the answer from the first three as the first entry for more calculations.

Let's look at a four-track example of 1:10, 1:48, 2:04 and 2:26.

Converting these to decimal values gives us 1.167, 1.8, 2.067 and 2.434 minutes respectively (calculated by track-length-in-seconds/60). Plugging 1.167, 1.8 and 2.067 (the first three values) gives us an LCM of 482,437.8 minutes - almost a year between exact repetitions. Now, if we plug in that number as the first value, and 2.434 (our fourth track length value) gives us over 587 million - or more than 1100 years between exact repetitions!

This is pretty amazing, but it is also a little deceiving. This is exact duplication - alignment of individual samples exactly. We are likely to hear similarities a lot more often than that - but it does show that we get complex repetition patterning with relatively few tracks.

In order to make tracks in a variety of lengths, we take the following steps:

If you prefer, you can use the class test fixture to try out your loops as well, although you can't add reverb or other processing in the test fixture.

One of the things that you will find is that open space - long segments of silence - makes the most interesting pseudo-generative work. In fact, simple percussive tones can often be used to make a very compelling track, since our ears will seek out (and find!) all sorts of poly-rhythms and 'inner tempo' changes as tracks move in- and out-of-phase. Combine this with other, non-musical sound (like natural or mechanical sound) and you can end up with a lot of complexity.

At this point, your ear becomes a lot more important than any rules. When you listen, what 'pops out' at you? Is it undesirable? Is it something you'd like to hear more often? Are there clashes that are problematic? Make sure that you save time to 'live with' your composition, and root out problem areas that you find out that you hate!

This sort of decision-making is the most important part of being a composer - and is the part that I will be listening for when I grade your work!

In-class Assignment:

Create the Audition tone files necessary to create a 4-chord progression and build it within Audition. Then expand the composition to be much longer and more ambient. Finally, split it into individually timed tracks to create an interesting generative mix. Test this mix in Audition or the class tester to make sure you don't have obvious-sounding repetition.

Assignment Due for Wednesday:

Create an generative installation audio system of four files. I will use the tester - or some similar tool - to listen to the results. Grading will be based on how satisfying the combination is, whether I find any parts irritating, and how the interplay between tracks works (or doesn't work). We will not be having a normal class - rather, we will meet in the library, and you will meet individually with me on a 15 minute schedule.