What to judiciously invest in next to improve SQ?

[Hifi_swlon]

The best money I ever spent was on 'Get Better Sound' by Jim Smith. It's only US$35.- and it gives you some great insight into how to get the best out of your system without changing any equipment. I would go as far as to say that unless you have set up your equipment the best it can be in the room you're not going to get anywhere near as much improvement out of whatever it is you acquire.

If you have money burning in your pockets and you can't do room treatment; speakers first, then the source.

Pim’s advice is sound.

Speaker isolation (de-coupling) was also useful in my space - much more so than coupling.

And playing with DSP and room measurement is useful just because you can see what small EQ changes (in the right places) do - sometimes it’s quite profound. And if you get bored you can change it some more and listen to new details in your albums.

If I could go back in time, id buy a umik-1 and learn a bit about acoustics/rooms before buying any kit/accessories. I left it far too late and it’s really the only way to tweak your setup, or not the only but vital IMO. Otherwise you just don’t know what deficiencies you’re trying to fix (and unless you’re incredibly lucky, you’ll have deficiencies in an average room that no upgrade will fix) and trial and error without any measurements is needle in haystack stuff.