As others have already mentioned, speaker placement and listening position placement. For my room it was moving my speakers close to positions that were recommended by Vandersteen (intersection of points in the room that are 1/7th or 1/5th or 1/3rd of the width and length of the room) and then moving my listening position from center top of equilateral triangle and back from there. Soundstage opened up and everything just sounds that much better. I've also started to learn how to use REW and am able to measure some of the changes to understand the different areas of my room. Lastly, adding absorption to side wall first reflections was another game changer for me (not free but DIY wasn't that expensive) and also added DIY bass traps to front corners.
Are There Improvements that Can Be Easily and Quickly Made Without Buying More Stuff?
I appreciate that there are many people on this forum who have put a great deal of thought and effort into how to improve their audio systems. Most of the discussion relates to upgrading equipment. This is natural as most people here want to improve their music experience, and better equipment is a way to do that. I’ve taken advantage of this and made 5 or 6 upgrades over the last year! The result has been great! But are there some simple steps that can be taken that can be overlooked by someone who is newer to audio?
As examples I’ve read that facing a sub towards something like the back of a couch will improve its sound. And for rooms with bad effects that can’t be fixed, move the listening position closer to the speakers.
‘What is your best tip for improving sound quality without buying anything?