Hi mate sorry for the late reply but its better late then none right
just kidding
I own the copper version and my friend had also the copper one until he heard the SS!
You know at first glance both sounds the same but when you really dig deeper and have flagship iems or headphones ohhh you get to hear the difference and its quiet audible you just need small concentration and open mined, let the music talk to you!
Overall the SS is cleaner more contrasty and sharper imaging. Tighter bass with a slightly faster slam.
It has a cleaner treble with less glaring and zingy peaky treble resonance. I don't know what it is but the copper version has this annoying eeeeky peakyyy squeaky resonance above the treble middle note decay.... In the SS its super clean natural and exactly how it should be!
One solution for this is set a different dac fillter in the copper version for slow roll off butttt then you are losing some resolution in soundstage and that's a big BUMMER!
Bass in SS is faster, tighter but also less hazy and less diffused. Its almost like more precised as in copper its stretched elongated and more fuzzy a little, its bouncy lushy kind of. Its not really something you'll notice until you do a/b directly with both devices on hand!
For vocals which for me I call it the mids hehe, is also a better tuning on the SS, as everything here applies the same way, more cleaner and better elaborated sounding vocals. It has a more normal proper sounding timbre here on ss. In copper its more warmish, slightly thicker and a little less sharpness becoming more cloudy and airy or less dense.
As you can see overall the SS is the 100% more accurate and exact tuning that aka should be.
The copper version derives a little to the softer warmer tuning with a more gentler bass but with a little spike in treble...
Dont be fooled like I was, I thought copper would give more bass and less treble!
WELL GOD DAM lmao its all the other way apparently *** lol now I need to get my self the SS and sell my copper