I bought a lightning to 3.5mm adapter to use my sennheisers in my iPhone 12 but they sound so much better plugged straight into my old Samsung s9. I’m no expert so I don’t know how to explain the difference but sounds so much more crisp and can decipher all the different sounds on Samsung. Can I make them sound better through my iPhone?
I don’t use Android or Samsung phones but it’s possible they have some DSP audio enhancements turned on that you like the sound of? iOS doesn’t really do anything like that.
If the Samsung’s headphone jack has high output impedance, it’ll give the Sennheisers a bit of a bass bump, which many people like. EQ (unfortunately not many options for that on iOS, besides an outboard device like the Qudelix5K) or an impedance adapter between the dongle and headphones can produce the same effect.