The simple solution for the TS will be a mechanical stop on the bass channel volume control.

So what is a simple way to do that stop?

 

So, what I should have padded walls?

They are somewhat expensive but Linkwitz Lab has designed audio speaker systems that use open-back speakers (even the woofer) which are set some distance into the room to use the back and sides of the room as a reflector to spread the sound and create a wide soundstage.
(Linkwitz was a well-known audio expert who helped design the Linkwitz-Riley crossover network which generates a flat crossover response between speakers).
Reviewers say the speakers essentially disappear, with it being basically impossible to locate them with your eyes closed.

 

The siple way to have a mechanical stopis to have a knob with some sort of pointer. Actual mechanical stops have been around for many years. But not all are aware of them