I HATE iheart radio if only because of the ads, I love a lot of the content but I would take the full force of the monkey's paw to the face to get rid of them
dB is a logarithmic scale: a 3 dB change represents a doubling or halving of power, and a 10 dB change is perceived as roughly twice or half as loud. A 5-10 dB cut would be highly noticeable, especially in tightly regulated environments like studios. To claim otherwise is inconsistent with basically everything relevant to this discussion.
I agree on the podcast front, and what makes it worse it's for their own podcasts which aren't generating them any revenue so why have 5 minutes of ads 3 x per show for your own stuff. Not unless the other podcasts generate revenue through ads, but I doubt it, just getting you used to it for when it becomes a Black Mirror episode and you must watch your ads as prescribed by the government (aka business).
I listened to a couple IHR podcasts, got supremely sick of the ads and deleted both of them. Now I watch to see the source of new subs and don't bother if it's IHeart.