CQ12t - can't work out how to use stereo input

Hi
Appreciate you help with this.
I am trying to play a video with sound on a projector - then use the headphone out (3.5mm) to go into the CQ12 - so the sound can be heard by everyone over the main L and R channels.
I have tried using a splitter and connected to the 1/4" inputs (separate stereo source inpiuts L and R on the CQ) and also tried a stereo 1/4 inch jack to a line in.
I have analogue input selected. I ger ‘some’ sound, but its crackly and distorted like a old modem dial up sound!
Can you advise me on how to do this properly?
I don’t want to use my bluetooth audio, because I don’t thisnk the video and sound would synchronise.

So - Here’s the setup:

iPad - playing video - using Apple TV - into projector HDMI - video plays fine (as does sound from the jack / speakers on the projector) - connecting headphone jack to CQ - to get the sound coming out from the main L and R of CQ…

Thanks!

If you are connecting to the headphone jack on the iPad, some HDMI adapters ‘borrow’ the audio from the headphone output. It’s not a mixer issue, it’s iPad. Go to Control Centre on the iPad (pull down from top right on current iOS) and go to the airplay bit, select headphones and the audio will stop going to the projector and go to the mixer instead.

UPDATE
Dodgy connection. Opened up ends of splitter cable, gave em a wiggle and a clean. All good now!