Kicks Progression

<?php

require(__DIR__.'/../lib.php');

$smp = [
    'file' => __DIR__.'/kicks1.wav',
    'start' => 0,
    'duration' => .15,
    'repeat' => 0
];

$tlen = 0;
$loop = [];

$void = $smp;
$void['gain'] = -100;

while($tlen < 8){

    $loop[] = $smp;
    $tlen += $smp['duration'];

    if($void['duration'] > 0){
        $loop[] = $void;
        $tlen += $void['duration'];
        $void['duration'] -= .005;
    } else {
        $smp['duration'] -= .01;
        if($smp['duration'] <= .08){
            break;
        }
    }

}

while($tlen < 16){

    $loop[] = $smp;
    $tlen += $smp['duration'];

    if($smp['duration'] < .15){
        $smp['duration'] += .01;
    } else {
        $loop[] = $void;
        $tlen += $void['duration'];
        $void['duration'] += .005;
        if($void['duration'] > .16){
            break;
        }
    }

}

while($tlen < 28){

    $loop[] = $smp;
    $tlen += $smp['duration'];

    if($void['duration'] > 0){
        $loop[] = $void;
        $tlen += $void['duration'];
        $void['duration'] -= .005;
    } else {
        $smp['duration'] -= .005;
        if($smp['duration'] <= .04){
            break;
        }
    }

}

while($tlen < 32){

    $loop[] = $smp;
    $tlen += $smp['duration'];

    if($smp['duration'] < .14){
        $smp['duration'] += .01;
    } else {
        $loop[] = $void;
        $tlen += $void['duration'];
        $void['duration'] += .008;
        if($void['duration'] > .20){
            break;
        }
    }

}


render([$loop], 'tmp.wav',  false);
exec("sox tmp.wav progression.wav trim 16 16 reverb repeat 1");