Hey Mitso!
I am glad you enjoyed it, thank you! I'll try to answer your questions as best as possible:
How do you get that high-end so warm and calm??
I don't know. To be honest, this is the first track I'm proud of the mix/master stages, but not sure exactly what to attribute to the final sound of the higher frequencies. I definitely experienced harshness while editing, just not sure exactly when and where. One of those areas was Reverb, surprisingly. I use Tal-Reverb 4 (
TAL - Togu Audio Line: TAL-Reverb-4) and if the Hi-cut was anywhere above the middle mark, the high frequencies would resonate and distort the track a bit. Another thing is definitely a balance of mixing while listening on different audio devices, compression, EQing and using a Limiter. If you use Ableton, I would suggest throwing an OTT (Multiband dynamics) and maybe lowering the threshold on the high frequency group, and other DAWs have similar plugins.
Does it has something to do with how steep my eq curves are??
I could only tell you that if I had the track itself to analyze. I started using Fab Filter Pro-Q 2 and I noticed a trick with the past two songs I edited. If you hover the mouse on the soundwaves in the plugin, it saves the highest position each frequency (Hz) reaches while the song is playing. If anything there is above the -10 db mark, it'll distort, resonate, or worse. You generally want a high Q to cut resonating frequencies, and a very low Q and gentle adjustments for broader sounds. Cutting everything off from 16-18.5 KHz and up can help remove unnecessary hissing, which just adds to the volume without really sounding good. Zen World's video helped a lot and was the last mastering video I checked out so far. I don't do everything 100% like he described, but the plugin introduction as well as general idea for the mastering stage was well presented.
YouTube
I reviewed one of your songs yesterday and don't think it was harsh, and neither does Shake It Off sound bad. I feel like I heard a lot of hard house with a lot more "brightness" to the tracks, so yours don't stand out negatively in that regard and I still enjoy them a lot! I'll check out Shake It Off in more detail a tad later today!
Peace