Music Box 2  Neural Network based Synthesizer

Download WinAmp http://www.winamp.com/player and listen to a live ogg vorbis stream coming from this synthesizer.  Enter this URL   http://63.199.138.245:8000/live.ogg  and click play.   The box can also now be "played" over the internet using VNC remote desktop capability.   We are working on a control web page that anyone can use.  The concept we have in mind is to set up the box such that it can be used as a "sound sample mine".   It is a one of a kind synth of extremely high complexity which is capable of producing an infinity of novel sounds.  We would like to see musicians use it to produce unique sound samples they would then use in their conventional synthesizers. 

Below is the box as of 4/2/08 as it is streaming audio from a garage in Palo Alto, Ca.. The PC on the left is an Ubuntu Linux machine running the MuSE compressor and Icecast2 streaming audio server.  

 

The PC is also running an arduino development environment that is used to upload programs via USB to the arduino board shown below which in turn drives 6 pulse width modulated streams into 6 low pass filters which are connected to 6 biasing voltages in the control panel.   You can see the control panel upside down with its cover off in the middle bottom of the picture above.  These biases control the operating points of neurons in the neural synthesizer.

Music Box 2 is a joint project with Forest Warthman, Simon Tam, John Adams and since 2007 Scot Gresham Lancaster.  It is a hybrid Analog neural Network/Digital 386 computer device designed to produce complex audio waveforms in realtime.  The box has produced many novel sounds never heard before some of which are included below.  Brief history of Box II.  Note that Hewlett and Packard started out building audio oscillators in a Palo Alto garage about 5 blocks from here.  

Please excuse the technology orientation of this page.   The performance artist who has actually used Box 2 to entertain live audiences is John Adams.   John has been affiliated with David Tudor and the Merce Cunningham Dance Company where Box 1 was used successfully in performances internationally.  

Simon Tam programmed the initial text based controls for Music Box 2.  Mark Holler later programmed the graphical user interface which allows weight setting with pen strokes on a tablet.  

Here are a few pictures that give an overview of the system.  

This is an overall view of the system.   From left to right, Mixer,  Analog Neural network system using 3 Intel 80170NXs, Std. Intel 386 PC with pen tablet in front of the keyboard, Analog audio control panel. 

This is a close up of the analog control front console.  Neuron biases in the lower left, feedback clock, delay line clock, cortical bias and gain control for chip in upper left.   Touch sensitive neuron bias controls on right.  

Patch panel for Analog Neural Network box.  Mostly Neuron outputs some inputs for feedback.  

Side view of Analog Neural Network showing three 80170NX neural network chips (mauve color squares with white labeling).  Also visible are some of the capacitor resistor components which define the circuit time constants.   The chip at top right with the rectangular white label is the analog delay line.   

Intel Neural Network Training System (INNTS) main screen.   (DOS program)

Weight setting screen for setting oscillator weights.   This is just the input array of 4096 weights.   There are another 4096 weights in the feedback array of this chip.  The size and color of the dark squares in this Hinton diagram like display indicate the polarity and strength of the weights set in the analog neural network used as relaxation oscillators.   columns correspond to Neurons/outputs and rows to Inputs.  

This is a similar view showing the weights for the array used to model cortical pyramidal cell behavior.   This array is more regular because two specific weight values per neuron are required to achieve spiking behavior like biological neurons.   Note the timings, pulse width and average firing rate of these artificial neurons is closely matched to the timing of real neurons.  

Then general architecture of the box includes oscillators and cortical neurons which enable the oscillators.   There is also a feedback path which performs an FFT using the 3rd neural network chip on an incoming signal and feeds the result to the cortical network.   Schematics

User's Guide to Music Box 2 Written by Forrest Warthman This was written prior to development of the Graphical User's interface but, it still contains critical information for understanding how the box operates.  

Some more content From Forrest's website is at http://www.warthman.com/box1a.htm

Box 1 was a simpler system with just one preprogrammed 80170NX in a box the same size as the Box 2 analog console.    It still produced very rich sounds better in some respects than Box 2 possibly because of inductors used in some of the oscillator circuits.