We have either B or P, but in Korean there're 3 sounds, ㅂ ㅃ ㅍ. We studied phonology a bit in elementary and B and P are very similar, P being the "silent" version of B. Try whispering both B and P and you'll see there's not much of a difference. There're a lot of pairs like this (D and T are ㄷ ㄸ ㅌ).
I prefer using the terms "voiced"/"unvoiced" over "silent" but yes. But there are other aspects to it in Korean--especially aspiration. My understanding is ㅍ is the only "p/b" letter that should be aspirated in Korean (similar to ㅌ and ㅋ and ㅊ). Native English speakers tend to aspirate voiceless stops (p, t, k) when they begin stressed syllables, but not when they begin unstressed syllables. For example, "paper" has first an aspirated p, then an unaspirated p.
The other distinction to be found is in "tenseness" where double consonants are more "tense" or "emphasized" but I haven't figured out how to explain that in English yet.
ㅃ is almost exactly like "B" in English. ㅂ is the one that sounds like something between "B" and "P" in English. Like Akira said, consult YouTube to hear what I'm talking about.
I'm sorry but you're wrong about ㅃ sounding like an English "B". It sounds like a hard P, not a B. And by "hard" I mean with no air coming out, just the 'P' sound and hold it for a little longer.
Wiktionary states that both words share the same pronunciation, with the IPA for both words being [p͈a̠ŋ]
But if you check Forvo, it sounds like 빵 is more "b" like and 방 is more "p" like
Saying ㅃ has more of a tense sound making it seem like your saying ㅍ when you pronounce it
I would say 빵 sounds more like bang in english where as 방 feels closer to pang when pronouncing them
ㅃ is between B and P. It's a double consonant. I think it would be the best to consult YouTube on this matter
Correct me if I'm wrong but ㅂ is pronounced like 'b' in English, ㅃ is pronounced like 'b' in Chinese, and ㅍ is pronounced like 'p' in English with aspiration.
But I think over time when people speak during normal conversations the ㅂ and ㅃ sound got close and sound similar.