.I’ve been using this free eq app for over a month now. It’s free (no trial then pay). I toslink from an Mac book pro lap top Spotify to my avr (toslinks cable has optical on other end). This set up is 95% of what I use for basic music listening...Anyways.. this app is incredible! When you start digging into everything it’s mid boggling that it’s free. 31 bands completely adjustable frequencies from a20hz band, up to a 20k band, and anything and everything in between to what ever frequency you want. You can add multiple closeness of same eq as many times as you want all running at the same time. Meaning you could have theoretical like 10 (or more) separate 31band eqs all adjustable to different frequency bands and running in sync. Having bands that go that low gives you lots of eq for the sub.
Performance it’s a huge jump in quality from running Spotify with no adjustments. I have a iPad also that has the Spotify app that’s in the iphones. This app has eq in settings. 60hz is the lowest And it’s only 6 band. iPad out gives hdmi ability (how I run it). And I’ve a/ b the two. It’s laughable how much better it is with this eq