I was messing around with speakers and forgot the headphone slot was on the side... I plugged them in the bottom instead.
Basically, if you don't like using the side jack for speakers or headphones, you can plug them into the AV OUT jack and they will also work.
Although, headphones should not be used because the audio will also still play through the Dingoo's built in speakers when using the AV jack
This will allow for Super BOOSTED Bass output on powered speaker systems.