Experiment, Experiment; What have been your most successful finds?

In responding to a post, I was reminded how the search for great sound can be compared to a lab experiment, factoring many ingredients.  My response in part:

Early on in my audio experience, I hooked up with passionate, energetic music lovers that were excited to do the work necessary to achieve great sound.  My 80's brick & mortar dealer removed his living room picture window to install Altec Lansings, for example.  My 90's mod/engineer friend would spend hours testing isolation approaches, including those "under the hood" of gear.  And yes, changes can prove sideways or negative, but, until you try.

Efforts are always rewarded.  In mixing digital and analog gear, often compromises are required, such as volume controls, wiring approaches and room requirements in placement.  In recent years, I've learned room/loudspeaker integration to be most vital.  Study, experiment with tuning a room (laser ruler a must.)  Arrival timing, room resonances, bass nodes, ceiling and floor bounce, distances between and to your speakers, the rake of the speakers and how it relates to your listening height.  Experiment, experiment.  When you find ***IT***, once found, "it"...will be readily apparent to you.  THEN, everything you do upstream will take on much more life and character in your system.  Experiments with wire, electronic gear, contact enhancement, isolation will begin to reveal themselves once these windows open.

And yes, many of these things cannot be measured, however, we each possess the best testing devices ever created.  I'm squarely in both camps. Measurements indeed matter, known hard science matters to get close, THEN the fun work begins!

Some experienced listeners seem to have personal favorites in what's most important to address, often, impressed by some game-changing experience in their journey...amp, TT, speakers, you name it.  Often, that can become the "focal point" for individuals, however, as many have voiced here, everything does indeed matter once the windows open to great sound.  Experiment, experiment.  Please share your experiments, thanks.

Stay Positive, Test Negative                             More Peace, Pinthrift