Hi mazkp,
To help us get a better understanding of the issue, we’d like to ask a few questions.
1. Is this happening with a specific pair of earphones or headphones only, or multiple?
2. Does this happen with all sound, or only sound in certain apps?
3. Does adjusting the audio settings help? This link explains how to do that: Adjust audio settings on iPhone
The above details will help us plan how to proceed.
If you're using Apple wired headphones, please check out this link, which has some information and suggestions that may help: Use Apple wired headphones
Learn more
* If you connect two headphones to an iOS device using both the 3.5 mm headphone jack and the Lightning connector, audio will play only from the last one you connect.
* When you use Apple headphones with earlier Apple products, you might be able to play audio, but not use other features. For example, volume or playback control might not work with Apple EarPods with 3.5 mm Headphone Plug on some iPod models.
* Find out what to do if your headphones don‘t work with your iPhone, iPad, or iPod touch.
* Get help with Beats products.
Thanks!