So I just got a pair oh YH-3s in today. I didn't really do much research and was trolling for low prices on some vintage orthos to try out for fun.
I didn't really know what to expect sound-wise but I was pleasantly surprised. Bone stock, they're amazingly good for what I paid for them, far better than my T50RP MKIIs were dead stock. They're mostly flat, but with slight smile curve, bass is punchy and only rolls off below 40-50hz and treble is a bit grainy but goes past 18khz (assuming I not hearing some sort weird of 1/2 harmonic or something), and the mids are just the way I like them, fairly detailed and grain free.
They aren't entirely without sonic flaws though. First, the treble is either strangely peaky or I'm having to crank them to make up for the total lack isolation because they fatigue me rather quickly ATM.
Second is the the way the soundstage is presented. I'm not exactly sure what it is, or how to describe it, but without some sort of crossfeed they are very fatiguing. I never listen for very long without some sort of crossfeed because I find it begins to fatigue me eventually, but the YH-3 did something that no other headphones has ever done. It gave me a headache after
one song. Fortunately a press of a button can fix that on my XM6, but I usually like try out something new without any crossfeed or EQ for a while to get a feel for it.
The XM6 has a fairly
strong crossfeed and they're still a bit fatiguing which may still be the soundstage or the treble as I described above. I haven't tried the obvious experiment of mixing it all to mono yet since it won't be much fun.