Binding posts tightening physics and drastic change


Hello to you guys. I just do not get it from scientific point of view. Here’s the case. As a Hi Fi man since many years I came to buy a pair of great monitor ( passive ) speakers ( the company has in this case nothing to do I guess but this is a second pair of the same speakers I had before ) I just happened to spend hours and hours to get the right position and sound ( as all monitors are very susceptible to set ups and so on ) and now this - as a purist I always tighten but not overtighten binding posts with banana connectors - yesterday I do not know why I made loose a bit all the screws on 4 binding posts so that they are not so strongly tightened up - and now the sound finally came to life and sounds much better with a bit more bass - I am no kidding in this case as I am an analytical listener. Please explain what the hell ? Almost anyone says that tightening should improve the sound - here it is quite opposite. Regards.
P.S. The more to add that there are no cable jumpers but metal (copper) links.
audiodav
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Exactly - the most important fact is that it works. No, the posts are not loose still tightened but I guess 30% - 40% less on each post that they used to be ( but of course they were never overtightened ) . Interesting.
How long were they used torqued down tight prior to being loosened?
@millercarbon - how long ? Quite long, definitely almost a year (I think since I got them - at start made them tight)
@erik_squires - my amp was on I think - no difference to it and not relevant. It has circuit protection board.

Was that the first time you moved your cables in some time? this would -could effect sound quality because if your cables have not been moved in a long time your basically reseating the cables and cleaning off the corrosion and making a better connection. always remove your cables periodically for this reason. Also before you evaluate new cables reseat you old ones first so your not taking in the cleaned contact surface as the new cable sound.

one thing we don't seem to think much about is contact corrosion from dissimilar metals (silver and copper, copper and iron for example). also copper corrodes quite fast on the surface.

It could just be that all the turning has cleaned off some contacts somewhere.

I do find that the harder the materials used in the binding posts and spades, the worse a connection you get. Tightening them down doesn't seem to help. Softer materials in the screw threads, spades or binding posts tend to work better.
Otherwise, it is possible there was some physical resonance happening that went away with the loose screws.

Best,

E
@glennewdick and @erik Thanks for replies but I can assure you if that was the case I would not start this thread. I plugged my cables thousands of times since, cleaned the posts and always made sure from time to time that the posts were solid ( but not overtightened ) for such replies I write in advance - no such things like neglecting something. Not touching for ages etc, please calculate this out.
@erik " Tightening them down doesn't seem to help. Softer materials in the screw threads, spades or binding posts tend to work better.
Otherwise, it is possible there was some physical resonance happening that went away with the loose screws. " Yes - thank you that can be the cause indeed !