Slow-Motion LibGDX

Hey I was just wondering how I could achieve a smooth slow motion effect in libGDX without having to affect every objects parameters. I am not using box2D or the universal tween engine if that is important

-Thanks for the help

float delta = Gdx.graphics.getDeltaTime() * 0.2f;

then I just multiply everything by the delta?
Thanks worked like a charm

Problem is: there is currently no way with gdx directly to slow down music as well.
I guess I need some direct openal calls on desktop only