I love podcasts. I've been listening to them since 2006. I've done a couple of idea validation interviews for my new business. They went great, and I think talking to customers is the right way to validate an idea. I still have more validation with customers to do but, in order to validate an idea you need to understand the space.
This seems super obvious now, but there's a podcast for basically every profession. In my case, it's a niche of small business owners. There's lingo, culture and all sorts of nuance that I need to know for those interviews. Additionally, since my interviews thus far are in person, there's a lot of bias that I'm picking up about my target customers. I needed some more random samples to add to my thinking.
I searched for "best podcasts about xxx" and presto, ten results. One of which was targeted exactly at the audience I'm looking to learn about. If you haven't yet searched for podcasts in your niche, about your customers, I highly recommend it!