QUESTION: Can you make the lowpass and delay functions explicit?

ANSWER: Sure, here is an example of what the lowpass() and delay() functions for a basic low-pass filter and delay effect might look like in JSFX:

function lowpass(sample) {
    // Define the cutoff frequency and resonance
    var cutoff = 1000;
    var resonance = 0.5;
    // Define filter coefficients
    var f = cutoff / 44100;
    var k = 3.6 * f - 1.6 * f * f - 1;
    var p = (k + 1) * 0.5;
    var scale = Math.exp((1 - p) * 1.386249);
    var r = resonance * scale;

    // Define filter state variables
    var xn1 = 0;
    var xn2 = 0;
    var yn1 = 0;
    var yn2 = 0;

    // Process the sample
    var yn = (sample * (1 - 0.5 * r)) + (xn1 * (1 - p)) + (yn1 * (1 - p));

    // Update filter state variables
    xn2 = xn1;
    xn1 = sample;
    yn2 = yn1;
    yn1 = yn;

    // Return the filtered sample
    return yn;
}

function delay(sample, time) {
    // Define the delay buffer
    var buffer = new Array(44100 * time);
    var index = 0;

    // Process the sample
    var output = buffer[index];
    buffer[index] = sample;
    index = (index + 1) % buffer.length;

    // Return the delayed sample
    return output;
}

The lowpass() function uses a basic implementation of a low-pass filter, which is a filter that allows low frequencies to pass through while attenuating high frequencies. The cutoff frequency and resonance are defined as parameters, and filter coefficients are calculated based on those values. The function also uses state variables to keep track of the filtered samples and update the filter coefficients.

The delay() function uses a buffer to store the audio samples, and it applies a delay to the audio by reading the samples from the buffer at a different position, based on the specified delay time. The delay buffer is an array of audio samples with the size of the delay time in seconds multiplied by the sample rate of the audio.

Keep in mind that this is just a basic example of the low-pass filter and delay, there are many other ways to implement these effects and you may need to adjust the coefficients and parameters to fit your needs. Additionally, you should also consider adding a feedback, gain and other parameters to make the delay more versatile.