String tension question

Raised saddle.

 

Soundpost adjustment. Less tension, further from foot.

 

Spiro solo E.

 

Well, the obvious: lighter strings.

 

And this is the only thing you really get less tension.

A raised saddle gives you a looser feeling because the coupling with the top is less. Just did that a few weeks ago with my adjustable saddle. Higher saddle needed for steel core strings (Spiro 4/4 Weich), lower saddle for synthetic core strings (Innovation Braided/prototype mix), both with basically the same tension to get a comparable feel. The point is probably the power needed to elongate the string by a certain amount. Synthetic core and gut (core) strings need less power to elongate by the same amount than steel core strings. But this also depends on diameter and core construction a bit.
Similarly a soundpost replacement that can make the coupling with the back a bit more loose.
A lower action gives you less power needed to press the strings down because they are less elongated (the shortest distance between two points is a straight line).

So it depends if you really want less tension or a looser fingerboard or pizz feel.

 

Not sure if you have a ply/hybrid/solid wood bass but...I have done everything to my Thompson RM200/hybrid to make it more playable w/a softer feel - wire tailpiece, lowered string height at string nut, light tension strings. These all helped a bit. I also have a solid wood bass that has a softer feel. I've come to the conclusion that the plywood back on the hybrid is causing the tension. The stiffness of the ply back translates to increased string tension. When I play the solid wood bass the back moves a lot, I can feel it w/my knee against it. The ply back on the Thompson doesn't move nearly as much.

 

Did you try to set the soundpost more away from the bridge?

 

I've tried everything including a new sound post and moving the position

 

Well, then the obvious, lighter strings.
Tuning a halftone down is like going from medium to light or from light to downtuned Solo.
In numbers at least 10% less tension than your current strings.

And the other obvious, but expensive solution: a different (shorter scale) bass for your strings...