If it's a well known company, I've found sites like levels [1] to be very informative and accurate. Otherwise I always just ask in the initial calls, no reason to beat around the bush. If you know what you want, you can ask what the salary range is and decide if it's worth it from there.
I ask in the initial calls even when I already know what the answer is. Sometimes, there's a discrepancy between the two that can be a clue that you should look more closely to see if the company is a straight-shooter or not.
[1] https://levels.fyi/