You will want some sort of amp. I connected a small speaker the same way at one point, and it did work but it was very very quiet.
Also if you're using linux make sure you turn up the speaker volume in your mixer - it's separate from the headphone or hdmi volume.
Oops, just realized this is in the Android section. I don't know if that speaker output is enabled in Android, I've only used it in Linux.
I know in Android, if you plug something into the headphone jack it automatically switches the output to that jack. I'm not sure what you'd have to do to tell it to switch to the speaker out.
Also if you're using linux make sure you turn up the speaker volume in your mixer - it's separate from the headphone or hdmi volume.
Oops, just realized this is in the Android section. I don't know if that speaker output is enabled in Android, I've only used it in Linux.
I know in Android, if you plug something into the headphone jack it automatically switches the output to that jack. I'm not sure what you'd have to do to tell it to switch to the speaker out.