Audio.play() causes tiny lag

Problem: I have made a flappy-bird like game using Three.js. Everytime I tap the screen, a "flap"-sound is played. However playing this audio causes a tiny lagg, which makes the game less smooth. If I remove the sound, all lagg disappears. The lagg only appears as the audio is played, not while the audio is playing.

Audio set-up: First I set up the audio like this:

var soundFly = new Audio();
soundFly.src = "https://dl.dropbox.com/s/tj7mxg26egzo4zx/flap.wav?dl=0";
soundFly.preload = "auto";

Next I load all audio upon starting the game (on button click):

function loadAudio()
{
soundFly.play().then(function () {
   soundFly.pause()
   }).catch(function (e) {
            console.log("soundFly - " + e)
            });           
};

Then, everytime I touch the screen, I play the sound:

this.soundFly.play().catch(function (e)     {
    console.log("soundFly - " + e)
})

This works great, but the tiny lagg appears.

Rendering: This is how I set up the rendering of the scene:

var clock = new THREE.Clock();
var delta=0;
clock.start(); //makes rendering timedependent

var render = function ()
{

delta = clock.getDelta();

//All movement is set using speed*delta

requestAnimationFrame(render);
renderer.render(scene, camera);
};

FPS: I have also checked how the audio.play() affects the FPS. My FPS is steady at about 59. But when I play the audio, the FPS drops to between 20-30, which probably is what causes the tiny lagg (see picture):

Audio.play() affecting FPS

I checked FPS using this:

console.log(1/delta);

And also outputting "flapp" to the console when touching screen.

I hope someone has an explanation to this!

Best regards, Joakim