Feedback Synthesis

This code demonstrates a feedback-based synthesis technique, where buffers are routed back into their own processing chain to create a rich, evolving drone. It showcases the use of buffers as processing parameters, illustrating how feedback loops can be used creatively for sound design.

feedback_synthesis.bell

## Define the total duration of the synthesized sound in milliseconds
$duration = 25000;
## Generate a random base frequency for the carrier oscillator
$fzero = rand(20, 80);
## Define the number of voices in the synthesis
$numvoices = 3;
## Iterate over evenly spaced pan positions for each voice
for $pan in arithmser(0, 1, null, $numvoices) do (
    ## Create a carrier oscillator with the base frequency and duration
    $car = cycle(@frequency $fzero @duration $duration);
    ## Randomly determine the number of modulation layers
    $times = random(1, 5);
    ## Apply frequency modulation layers
    for $i in 1...$times do (
        ## Generate a random modulation frequency in a given range
        $fq = rand(0, 1).scale(0, 1, 40, 8000);
        ## Create a modulator oscillator with the computed frequency
        $mod = cycle(
            @frequency $fq @duration $duration
        );
        ## Scale the modulator output to a desired amplitude range
        $outmin = rand(0.1, 0.9);
        $mod = $mod.process(scaling(-1, 1, $outmin, 1));
        ## Generate breakpoint functions for dynamic range limiting
        $low = for $x in 0...random(0, 10) collect [$x rand(-1) 0.25];
        $hi = for $x in 0...random(0, 10) collect [$x rand(1) 0.25];
        ## Apply modulation and dynamic range control
        $car = $car.process(
            ## modulate amplitude
            multiply($mod) 
            ## apply range limiting
            pong($low, $hi) 
            ## normalize to 0dB
            normalize(0) 
        ) 
    );
    ## Transcribe the processed carrier with spatial positioning
    $car.transcribe(
        @pan $pan
        ## apply gain envelope
        @gain [0 1 0] [1 0.5 -0.5] [2 1 0.5] 
    ) 
);
## Render the final output with normalization applied
render(
    ## Normalize audio to -12 dB
    @play 1 @process normalize(-12) 
)