Heat / crackling noise

Hi there a__w,

Have you seen any temperature alerts appear on the screen of your iPhone? If not, there shouldn't be any cause for concern. It's normal for your iPhone to get warm in certain situations. Learn more about that here: If your iPhone or iPad gets too hot or too cold - Apple Support

Regarding the sound you're hearing during phone calls, does this happen with every call? Are you using the iPhone speaker, receiver, or headphones when this happens? What kind of signal strength are you seeing for your cellular network connection when this occurs? Send over some details and we'll take a closer look from there.

Thanks.

a__w,

Have you tried connecting your device to a different Wi-Fi network or a cellular network to see if it impacts call quality? You can find some additional troubleshooting here: If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support

If you have additional concerns regarding your battery you can reach out for support here: Get Support

Take care.

Hey a__w,

We'll focus on the static you're hearing with any type of call you make with your iPhone.

If you turn on Wi-Fi Calling, does the static when making cellular calls disappear or lessen? Here's how to turn that on: Make a call with Wi-Fi Calling - Apple Support

With FaceTime calls, the static your hearing could be interference-related. This article shows you how to check: Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support

If you're still hearing static with either a cellular or Wi-Fi connection, please reach out to Apple Support who can look into this issue further with you: Get Support

All the best.