LMMS messes up when playing two sounds at once

Having trouble with LMMS? Ask about it here.
I recently downloaded and installed LMMS, and it works perfectly fine... as long as I don't try to play more than one sound at once. But as soon as I try to play a chord or play the oscillator and drums simultaneously, instead of the sound I want, I get some satanic, torturous noise. Does this usually happen? Is it just interference that I can maybe overcome messing around with the phase? Or is it that my computer can't manage doing everything it would need to do at once? Any help is appreciated.
https://en.wikipedia.org/wiki/Clipping_(audio)

Computers cannot calculate with infinity, only finite numbers, so all digital sounds has an upper limit of how loud / high volume the sound can be. Let's say the maximum volume is 1. If you play two notes with volume at 0.4 each, the sounds will sound ok cause the volume is 0.8.If the volume on each note had been 0.6, the computer couldn't calculate the highest amplitude (volume), so what would happen? The computer would clip the soundwave so it was never more than 1, but of course you will then loose information! You will loose everything from 1 to 1.2. And that is why your hear noise.

Solution to your (and everyones) problem, turn down the volume. You can do it on each individual note, on the instrument itself or the master channel in the FX mixer if you want your whole song to be less loud in volume. This is just a basic thing with all computers, not a fault with your computer, you or LMMS :)
Alternatively, you can keep the volume all the way up and just put a limiter effect in the master FX channel.