I spent my life listening to people play instruments. When you do so long enough, you know what horn sounds like in person. When you’ve heard a band live dozens of times you know what they sounds like when they are actually playing. The best experiences I’ve had are when a well recorded piece of music makes me forget for a second or two that I’m actually listening to a recording. So I look for the sounds I know to sound that way. How many recordings and setups give horns that sound of tin? So many systems people swear are accurate because of readings on a machine do this and it’s hard for me not to think they lack the real world experience with brass instruments to know it’s inaccurate. There’s a reason music is not mastered by machines or by numerical values alone. Then I also look for distortion that is clear, often in the bass. I’ve listened to a huge pipe organ hundreds of times (Balboa Park) and in person they do not sound like synthesized bass. An 808 and a pipe organ shouldn’t sound the same even as the hertz drop. I’ll that said I’m no golden ear and I’m sure there are biases in my judgement but at the end of the day I’m only trying to impress myself.