avar LibCanvasAudio = function (file) {
    this.audio = new Audio;
    this.src(file);
};

LibCanvasAudio.prototype = {
    src : function (file) {
        var codec = this.getSupport();
        if (!codec) throw 'AudioNotSupported';
        this.audio.src = file.replace(/\*/g, this.getSupport());
        log('using ' + codec);
        this.audio.load();
        return this;
    },
    getSupport : function () {
        return !this.audio.canPlayType ? false :
            this.audio.canPlayType('audio/ogg;')  ? 'ogg' :
            this.audio.canPlayType('audio/mpeg;') ? 'mp3' : false;
    },
    cloneAudio : function () {
        if (window.opera) { // Reported Opera bug DSK-309302
            var audioClone = new Audio;
            audioClone.src = this.audio.src;
        } else {
            audioClone = this.audio.cloneNode(true);
        }
        audioClone.load();
        return audioClone;
    },
    gatling : function (count) {
        this.barrels = [];
        this.gatIndex =  0;
        while (count--) {
            this.barrels.push(this.cloneAudio());
        }
        return this;
    },
    getNext : function () {
        var elem = this.barrels[this.gatIndex];
        ++this.gatIndex >= this.barrels.length && (this.gatIndex = 0);
        return elem;
    },
    playNext : function () {
        var elem = this.getNext();
        elem.pause();
        // firefox 3.5 starting audio bug
        elem.currentTime = 0.025;
        elem.play();
        return this;
    }
};

var shotSound = new LibCanvasAudio('explosion.*').gatling(6);

window.addEventListener('keydown', function (e) {
    shotSound.playNext();
}, false);