[PI 3B +][armv7] sound plays slowly and deeply

[crumbler]

Hi,

this is unfortunatly a post with not so much information, since I just couldn't figure out the problem. When I play sound on my Raspberry Pi 3B using the headphone jack, it plays a tick to slow (and by this also the tone is distorted accordingly). Speeding it a bit up using $this->bbcode_second_pass_code('', 'mplayer -speed 1.1') it sounds quite nice.

Any Ideas?