Week 3 – CC1 – Desktop Music Environment

This week we were introduced to a small application named Sinusoidal Partial Editing Analysis and Resynthesis or SPEAR for short. SPEAR is an application for audio analysis, editing and synthesis.[1] As far as editing goes not only can you cut along the vertical plane as most other editing programs do along the wave form, this allows you to edit along the horizontal plane thus eliminating specific harmonics or overtones from the sound. I mentioned wave form just then, but SPEAR doesn’t represent it’s information as a wave form. It displays hundreds of little lines which represent the individual partials hence the word “sinusoidal” in it’s name. It transforms a complex waveform into it’s sinusoidal parts by a process called Fourier analysis named after Joseph Fourier.[2] I’d never seen an editor function like this or even heard of Fourier analysis before and I was impressed by such a small, and free I might add, program.

Different levels of amplitude can be identified by the darker or lighter shading of the partials. Darker for louder, lighter for quieter. There is also a pallet with editing functions that allow you to select vertically, select horizontally, timestretch, adjust the amplitude and frequency and also a lasso tool that allows you to select individual areas to edit.
We were asked to take our paper sounds that we had recorded last week, stick them in SPEAR and experiment with it’s functions. This is what I came up with.

Sound 1

Just some cutting and hacking away to start with.



Sound 2
I imported this at both 100 Hz and 8000Hz. At 100Hz I couldn't hear any difference but at 8000Hz (which took forever to import by the way) a lot of bottom end was missing. I didn't end up saving the 8000Hz version, but after chopping and playing around with the control sliders came up with this.

Sound 3
I cut holes in this one, pitched it down and cut some mids. It ended up like some weird howl. Pretty cool though.

Sound 4

I copied square shapes from the file and pasted them back on randomly. I stretched these squares up and down. It sounds a bit 'staticy' like a tv.

Sound 5

Instead of doing random things, I thought I'd do a cross thatch pattern all over it. That didn't really sound very interesting at all so I selected sections along the time scale and pitch shifted sections up and down. I also randomly selected parts with the lasso tool and deleted small sections.

Sound 6

I removed a lot of partials from this one. I listened for 'weirdness' and kept those that I thought were interesting.

Overall it's a pretty cool application. Now that I've downloaded it, I'm sure I'll come up with other weird and wonderfull sounds in the future.

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[1] Michael Klingbeil 1995-2007 “SPEAR Sinusoidal Partial Editing Analysis and Resynthesis” http://www.klingbeil.com/spear/ (19 March 2007)

[2]paraphrased from: Wikimedia Foundation 2001 “Sine Wave” http://en.wikipedia.org/wiki/Sinusoidal (19 March 2007)