Hello Absynth
With the start of the 2008 Spring semester at Berkleemusic.com, I’m looking forward to the arrival of Absynth in my online course, Sound Design for the Electronic Musician. I spent the beginning of this year revising the course, and I’m excited by the educational opportunities Absynth will provide. So, what makes for a good teaching tool anyway? As with anything, we learn by doing, and you’ll learn from your experience with any electronic instrument. However, in my mind, a tool that’s particularly well suited to teaching is one that helps you make connections with larger concepts or principles. Absynth does that in a couple of useful ways: by using absolute values and providing time and frequency domain displays of waveforms.
Most synthesizers use arbitrary values for parameters. By arbitrary, I mean that a given value has no correspondence to an objective measure of a particular setting. For example, in Reason we can set a filter cutoff frequency to 85, but 85 what? Don’t we usually use Hz to describe frequency? As far as I can see, the values used for the parameters in Reason are totally arbitrary. By and large we’ve gotten used to this way of working with synthesizers and even in some effects processors. Take a look through your collection or virtual and hardware synths and see what you find.
Two things contribute to this, first is the legacy of analog instruments, which serve as the model for many current synthesizer designs. Back in the days of the Mini Moog, there were no display readouts of values. You used your ears and adjusted a parameter to taste. Any frequency values on analog gear is an approximation anyway, and it’s just not possible for a potentiometer to set a specific numeric value. Second, while the arrival of digital control and MIDI meant that absolute display of values like filter cutoff was more of a possibility technically, manufacturers often didn’t see the need. MIDI control has a range of 128 values in most implementations, so it can only address 128 specific values in any range. While a MIDI parameter value of 87 might correspond with a specific frequency, manufacturers often spared the user those details. Yamaha in it’s DX line of instruments was a notable exception here.
To my knowledge, the first synthesizer to fully implement absolute values for parameters was the Kurzweil K250, introduced in 1984.* Filter cutoff frequency was displayed as Hz, levels as dB, LFO rate as Hz, and time values, including envelope segment durations, in seconds. This made it a particularly powerful teaching tool, and it was a staple in the Berklee Music Synthesis Department labs for years, followed by the K2000 series. Absynth follows in this tradition by using absolute values for any parameter.
One synthesis concept that’s difficult for many students to grasp at first is the relationship of wave shape to spectrum. Early analog synths usually had two or three waveshapes available in their oscillator sections. With the arrival of digital oscillators and wavetables, synthesizers offered a greater selection of single cycle waveforms, however these were often displayed numerically. We see this in Reason’s Subtractor where waveshapes beyond the basic geometric staples are selectable by numbers 5 through 32. While a description of timbral characteristics can sometimes be found in the instrument’s documentation, we often don’t see the shape itself or the actual spectrum, the number and level of individual partials.
Waveform Display in Absynth
Spectrum Display in Absynth
As in most software instruments, Absynth has a number of waveforms available in it’s three oscillators. In addition, you can create and save your own waveshapes use the Wave Window editor. This unique editing environment lets the user select between the familiar time domain waveform display or a frequency domain display that shows the number, level and phase of individual partials. You use a pencil tool to simply redraw a waveshape in one window and the change in spectrum is displayed in the next. Conversely, when you change the level and phase of the displayed partials, you switch views and see a new shape. Pretty cool…
While Native Instruments boasts of many more exotic and even revolutionary features in Absynth’s promotional materials, absolute values and graphic displays are some of the basic features that make it a powerful tool for learning about sound. Hello Absynth…
Multi-segment Envelopes in Absynth
* While the Synclavier, Fairlight and perhaps other high-end systems incorporated absolute values, I’m thinking here of instruments that mere mortal, working musicians might be able to afford.
