You’re saying each mp3 is ~10MB? That’s probably 320Kbps quality, so should be at least better than topical 128Kbps. My maths: 10,000,000B ÷ 240 seconds song = 41,666B(yte). 41,666B × 8(bit) = ~333,333b 333,333b ÷ 1,024 = 325bps (thinking kibibit vs kilobit depending on your IS) (again, rough numbers)