I've tried a lot of tweaks over the years, mostly back in my analogue days. I've decided there are two kinds, those which are electronic or physical and taken mostly on faith like cones or raising wires off the floor which usually cause a difference with indeterminate rewards and the more physical ones like 25 pounds of lead on top of speakers or moving the tv from in between the speakers to the long wall which are no doubters. Hands down best tweak ever was running the air tubes from the ET II aquarium pump through a plastic 5 gallon gas can filled with wool batts; much better defined bass. Sorry, Sam, I find myself wishing the tube was a little bigger, I could at least take it to the beach.
Snake oil and tweaks that work!
This is in no way intended to bring out argument but discussion of tweaks people have tried and have found success with. I know there are at least 50% of you out there that think everything in audio is snake oil, and you are initialed to those opinions. Please don't make this your battle field! If you want to start an opposing thread calling us nuts and getting in arguments please do, it might be fun to have both going. I want this one to be an informational for people who want to try things. I for one have tried a lot of the recommendations in Stereophile each month, most don't work for me, but I have found a few things that do work. #1 tweak: Speaker location. Even a 1/16" can make all the difference. I try to play with this about every six months. A dedicated circuit from the panel with 10ga. wire had a very noticeable improvement. Cables and wires matter, some have been good for my system, some real bad. We have plenty of threads covering this so lets no go there. The "Bedini Ultra Clarifier" works amazingly well for me, I know it's crazy but it works! The Cardas caps I got for X-mas really worked, they produced a more quite background, go figure. Black Diamond Racing "the Puck and the Shelf " have been great improvements, all the different cones I've tried change the sound, I haven't found one I would recommend. The Audio Prism Quiteline filters work great, but power conditioners and RFI/EMI ferrets did nothing. The last thing that has helped me is furniture location, I find if I move something only an inch it can help or hurt. I look forward to hearing others experiences.