Diamond Life is a pretty thin sounding album - designed to sound good on 80s ghetto blasters (boom boxes). Yes, I was there... Though I hated the album when it came out for it's "slick, shiny" feel that gave off an over-produced feel, with a whiff of sophistication that seemed aimed at making yuppies feel they were being cool by owning it. I came to like it as the years went by... But it still sounds kinda stark, without the impact and the last degree of groove and funk it should have. It is arguably a victim of early CD era mastering, where there was a tendency to master CDs to sound "bright".
One thing that better hi-fi does is to make the differences easier to hear. Fast music will sound faster, slow music slower, echoey open sounding production will sound more spacious, claustrophobic recordings more up-close and personal. etc. So Hugo 2 and HD 800 S is extremely revealing and will make the differences really obvious across your music collection. The Stax headphone guys have a good word for how revealing HD 800 (S) is: plankton. You hear the tiniest most inconsequential things.
HD 800 S appears to be designed for Sennheiser's headphone amps/DAC-amps. These are engineered with a high output impedance to add bass. So, it's reasonable to do EQ to add some bass. HD 800 S also has some extra bass resonance/distortion engineered into its sound, to give it a more "fun" character.
I don't use EQ: I found that I was always fiddling. It's an evil waste of time as it makes me think: "ooh I could make this sound a bit better by ..."
One thing I love with my system is the way HD 800 S "disappears". It's not so much that the sound transports me to the recording venue, as the headphones don't seem to be on my head. Also I find HD 800 S to be an exceedingly emotionally communicative headphone - and Chord DACs can make fireworks sound emotionally engaging, so the combination is a real show!
It's always good to listen to new music with your shiny new hi-fi: you have no idea how that music is supposed to sound. This stops you thinking about the differences from your old hi-fi.
Here's something to take your mind off the sound:
http://www.nilsfrahm.com/works/sol/
It's a free album by Nils Frahm played on an amazing piano with super resonant scale and extremely low bass notes (10 foot/3m long strings!). Amongst the plankton you'll hear him, I guess, pressing a button on his digital recorder to mark the tracks: it's an improvised album recorded in one take.
So ... it's taken me the entirety of Diamond Life to write this post, mildly distracted at times by the album...
Now playing: Sade - Why Can't We Live Together