Change audio output in iOS (AV/HDMI/Headphones/..)?

I have an iPad Pro 10.5 which has an AMAZING sound quality (thanks to those 4 really good speakers built in). I just bought an Apple AV Adapter so I can connect my iPad to my 122cm TV (I just got too) when I would like to.
Now as soon as I connect it, the audio output goes to the TV (through the HDMI, but the TV's stereo speakers do not sound as the iPad Pro's 😀)..
Is there a way to keep the sound comming from the iPad and have only the visuals go through the HDMI?
I was expecting a little toggle or something in the Control Center (at the "Volume bar") to chose whether I want it to go through the AV or have the sound from the iPad itself, but nothing.
(I checked online and did not find anything on this really)

iOS 12 (even iOS 11.3)

Thank you!