Wood privacy fence - planning over the top? Alternatives?

But I can hardly imagine a normally thin wall with the perfect effect of our shed, even with the best engineering skill using particularly dense, specially shaped stones :-/

In my head, I am currently building a very narrow, very tall, 20-meter-long shed along my entire border. :D I wonder what that would look like? It would definitely be practical, you could store all sorts of things under it. :D

This is about bass. It has already been mentioned that it can only be dampened by mass.

Repeating misconceptions does not make them true.

What would flexible obstacles be?
And do you have an idea which materials could be used as diffusers outdoors?

I think I advised in several threads here around 2018 (and I don’t have time to look it up right now) both on the topic of sound and strong winds to use combinations of absorption and diffusion, for which small firs / thuja / conifers are well suited (which are also available artificially if you don’t want to wait for growth).

Didn't someone write in this thread that their 2-meter-tall, very old and dense thuja trees are practically useless?

Didn't someone write in this thread that their 2-meter high, very old and dense thuja plants barely do anything?

See among others post #101 We also have such "monsters" at the property boundary. In my opinion, they mainly serve as privacy screens.

Didn't someone write in this thread that their 2-meter tall, very old and dense thuja trees basically don't do anything?

Yes, I did. Unfortunately, that's the case for us.

These are about 20 meters of thuja hedge, behind which the neighbors have their seating area and their music system. I can hear everything almost as well as in the spot without thujas. Slightly muffled, yes, but that just feels like the neighbors turned the volume down a bit.
On the other side of the garden, we border a field/horse paddock. There are also some thujas there, which are somewhat... umm... out of control. They used to be 4 meters tall (now only 2.5 m) and are easily 2 meters wide. I can still hear horses snorting, grazing (and snoring) very well from over there.

I don’t want to dampen hopes; maybe our hedges have become hollow inside due to their age – but they really don’t do much for us. Against wind, however, they are fantastic.
If the choice is between hedges and a wall, based on my personal experience I would definitely recommend the (solid!) wall. And of course, a professional for advice :)

I once read about coconut fiber mesh that could be good at absorbing sound. However, I have not yet found good offers to buy it in larger quantities and preferably in long / wide sheets. There is also this "cold foam" with the triangles that is used in music studios, for example, but I doubt that it is suitable for outdoor use?

Coconut fiber mesh does not absorb low frequencies sufficiently; with that, you buy yourself work and frustration but no results. The egg crate foam from studios serves—similar to the function of coconut fiber mesh—absorption to prevent reverberation effects. Here too, the effectiveness decreases with frequency.

Didn't someone write in this thread that his 2-meter-high, very old and dense thuja hedges basically do nothing?

To understand that there can be no construction measure approvable for you, familiarize yourself with the propagation of sound waves depending on frequency. Lower frequencies spread spherically, higher ones directionally. Therefore, you can wonderfully put something in the way of higher frequencies but not lower ones. A 2 m thuja hedge absorbs many middle and higher frequencies and some of the low ones; it deflects some others, but most "spill over" and reflect off your house wall or wherever. If I have formed an approximately correct picture of your sensitivity to bass rhythms, this measure will bring no relief either. There are exactly three solutions: 1. An agreement with the neighbors that leads to acceptable quiet times 2. A change of your own attitude and perception (I know that this works with help) 3. A withdrawal from the situation