Is All AdMob Interstitial Ads Muted by Default?

I see a lot of android app show AdMob interstitial ads without audio that users can unmute than by clicking a speaker button in the ad.

Are all those interstitials muted by default?

Or Do I have to use this method for that AdMob Global Settings

MobileAds.setAppMuted(true);  

https://stackoverflow.com/questions/67041298/is-all-admob-interstitial-ads-muted-by-default April 11, 2021 at 11:51AM