Music 220a - Final Project: "Vox Box"

Gio Jacuzzi, 12/13/13

Vox Box is a vocoder. Okay, but what's a vocoder?

That seems cool! So what does that sound like?

  • It sounds a little like this...

    • Killer! What's it made out of?

    Voxbox is a vocoder made from two components: a synthesizer and a controller. The synthesizer is created from a modified Triangle Oscillator in ChucK. 5 voices of the synthesizer are instantiated, so in effect there are 5 TriOsc unit-generators running in parallel.

  • ChucK code for the synthesizer

    • The controller, on the other hand, is a java-based swing application that communicates with ChucK in real-time via OSC and alters the parameters of the output signal and calls on one or more of these voices to sound.

  • Java code for the controller

    • Sweet, so how does all the walkie-talkie stuff work?

    Voxbox takes in the user's mic input, applies a Fast Fourier Transform, and stores the resulting data array in a spectrum. Simultaenously, the output from the user-controlled synthesizer is routed through another FFT, and the resulting data array is again stored in a separate spectrum. The spectrum from the mic input is then mapped to that of the synthesizer input, and the resulting array is passed through an IFFT to the output, which essentially does the FFT processing in reverse, creating a new modified sound singal based on the data from the mic and synth analyses.

    All of this processing happens continuously while ChucK listens for OSC messages as input, and alters the parameters of effects and filters daisy-chained through the output in response. When a musical key is pressed from the controller, ChucK goes to one of the 5 voices, adjusts it's oscillation frequency to the frequency matching the musical key, and then routes the oscillator's output signal to the main output signal. Then, when the musical key is lifted, the oscillator's output signal is removed from the main output signal, and the voice waits silently until it is called on again.

    Awesome! Are there effects? What is it like to play?

    There are! Currently, Vox Box supports basic filtering, reverb, chorus, echo, and pitch modulation. Because it's as simple as speaking while playing with your keyboard, it's pretty fun and addicting... just don't use it with headphones in a public place, obliviously "do-wah"ing to yourself like a maniac in front of passersby like I have :)

    In case you're wondering, a lot of the drive for this project came from my love of the classic "Frampton Comes Alive!" album from 1976. Peter pulls out these amazing talk-box solos, and I've always loved the idea of talk-boxes and vocoders, because it adds a whole separate dimension of expression to your playing, no matter what the instrument. So, in honor of Frampton, I made a humble demo of myself playing the Vox Box along with him to "Do You Feel Like We Do?", which is linked below. I had a lot of fun with this project; thanks for checking it out! - Gio

  • "Do You Feel Like We Do?