iPhone audio having issues while using splitter

Hello Ace_-13,

Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with your headphones. Try the steps here to see if they resolve the issue: If your headphones don't work with your iPhone or iPad - Apple Support

"If your headphones don't work with your iPhone or iPad

Get help when you can’t hear sound from your headphones, the sound is muffled, or your microphone doesn't work.

Update and restart your iPhone or iPad

Make sure that your iPhone or iPad has the latest version of iOS or iPadOS. Then restart your iPhone or restart your iPad.

If your headphones still aren't working, follow the steps below for your issue.

Check for debris, damage, or loose connections

1. Check for debris in the headphone port on your iPhone or iPad.
2. Check your headphone cable, connector, remote, and earbuds for damage, like wear or breakage. 
3. Look for debris on the meshes in each earbud. To remove debris, gently brush all openings with a small, soft-bristled brush that's clean and dry. 
4. Firmly plug your headphones back in. If your iPhone or iPad has a case, you might need to remove the case to get a firm connection. 

If you can't hear any sound or if only one side of your headphones works

1. Adjust the volume with the volume buttons on your iPhone or iPad, or use the Volume slider in Control Center on iPhone or Control Center on iPad. 
2. To see if you need a replacement, try a second pair of headphones. If the second pair works, contact the manufacturer of the initial pair and ask if you need a replacement. If the second pair doesn't work, contact Apple Support. 

If your microphone doesn't work

1. Make sure that your headphones have a built-in microphone.
2. Check your microphone for blockage, like debris, lint, or plastic packaging.
3. To see if you need a replacement, try a second pair of headphones. If the second pair works, contact the manufacturer of the initial pair and ask if you need a replacement. If the second pair doesn't work, contact Apple Support.

Still need help?

If your headphones still aren't working, contact Apple Support."

We hope this helps.

Cheers!