how to play music in speaker when headset is connected

[Only3uses]

I want to play sound through my phone with the headset on

 

[Saga Lout]

You might be able to do it through Bluetooth with a suitable speaker but the headset socket is set to cut the phone's own speaker as soon as it's put to use.

 

[audie-tron25]

Although it may not be possible to do what you are trying to do, you could also get a 3.5mm splitter and connect your headset AND another speaker to it. Is this iOS or Android (or something else)?