Wood privacy fence - planning over the top? Alternatives?

But the case here is apparently different. That's why I would openly seek a conversation here. Feel free to tell them about your experience in the old apartment, that since then you have been a bit sensitive. Whether they would be willing to test a little with you. And above all, that they pay attention to turning off the music when they are no longer outside.

That worked well last time, I had mentioned that we would like to watch TV and asked if they could turn off the music when they are no longer outside. Then it was immediately off. Maybe that also helped to make clear how much the bass affects us. If I had one wish, I would wish that they are not into listening to music outside. :D I can't say which I find worse, inside or outside. Both are annoying. Inside because I feel disturbed in my protected space. And outside because it basically makes my garden unusable. I once made a video, but I don't think you can upload that here. Doesn't matter anyway. The idea now is to proceed in stages. We initially decided on the privacy fence made of wood. First, because it creates a visual boundary, sections off our own area a bit, and also gets rid of the view of the unwanted shed. Also, I have something tall along the boundary to let ivy and clematis climb on, which I find visually appealing. I know that this is not a reliable sound insulation – but at least there is SOMETHING between the neighbor’s speakers and my terrace. So far there is nothing at all, not even a blade of grass, and spatially it's only 5-6 meters. :) When that is up, we want to see how things develop. How often they want to listen to music outside during the summer, how well we can talk it over with a beer together, and whether they can understand my situation. Turning down the bass a bit could already help a lot, and the neighbor himself said over the weekend when we talked briefly, "You can talk about everything" – and he's right. Maybe I also have to represent my position a bit more clearly. I never want to bother anyone because of my sensitivity, but on the other hand, you have to honestly say that their volume is a bit too high for a Sunday afternoon, if I look at it soberly. Maybe we can meet somewhere in the middle. I also have to overcome my hesitation and dare to address my problem. That would be cheaper at first than investing 5000€ in soundproofing. Actually, you shouldn’t really need that on a private property. Other neighbors probably don’t mind because no one is behind them, and on the other side there is only a path and some nature – the next neighbor is clearly farther away than we are. If the first steps don’t help and they still play disturbingly loud music frequently in summer, we will consider how to make our wooden fence "denser." Then there will already be something set in concrete that covers the entire area. The idea would be to work with materials that absorb sound and are suitable for outdoor use. For example, cork or coconut fiber – and to somehow attach that creatively to our fence, as extensively as possible.

I think you need to clarify for yourself and with your husband how much this burdens you and how much more peace is worth to you. If you are simply that sensitive, then a good and well-planned noise protection measure is quality of life. And I would rather invest a few thousand euros in that than get annoyed by every perceived noise. And maybe also burden my less sensitive family because of it. Or consider selling. It is annoying, but as long as you don’t move into a hermit farm, it is normal. You can also look at it the other way around: no one wants to live next to extremely sensitive neighbors who keep bringing up the issue. That is stressful too. You move into a house to finally not be reminded of house rules every time there is noise from the neighbors.

What I was actually getting at with my question: if what bothers you the most is the thumping in the living room with the window closed, I might consider a different, better-insulated window. Maybe it would even be enough to properly adjust the pressure seal on the window if the window installer was careless there.

As a former person disturbed by noise, I had to gain my experiences in this regard and was very thoroughly informed by the friendly people in blue. And it was really no longer a matter of sensitivity when schnitzels were still being pounded at 2 a.m.
Quote: "You cannot forbid anyone from preparing food after the late shift." Fortunately, the neighbor was so foolish as to regularly listen to loud music, but even then I would not have gotten any further without another neighbor who was also sensitively disturbed and incredibly persistent.

That's just how everyone gains their experiences. We had the opposite experience. The (un)friendly people in blue explained to us that on Sundays all music must be stopped because it disturbed a neighbor, even though it was really quiet.

That worked well last time, I mentioned that we would like to watch TV and asked if they could turn off the music when they’re no longer outside. Then it was immediately off. Maybe that also helped to make clear how strong the bass is in our place.

So they seem to be friendly loud neighbors. At least.

If I were in your place, I would still start by "validating" the volume with a measurement. I am also very sensitive to noise. There are definitely people around me who are much more tolerant when I already say: wow, they shouldn't be that loud.

What I mean is: just because YOU feel disturbed doesn't mean it has to be that way for everyone (but that also doesn't mean you should just accept it).
However: if the music is really measurably too loud, in my opinion you can clearly let the neighbors know that this is not okay.

I think you are currently going in circles. You really want the others to be quieter, but do they actually "have to"? Is everything within limits and are you the only one who feels disturbed? If that's the case, maybe you just have to work a bit on your basic attitude. Someone already mentioned a hermitage farm. We are not alone in the world and the neighbors also have their rights.
Our neighbor complains about noise (from her point of view) from the nearby playground. I enjoy hearing the children laugh. She complains about the new building plots right across the street. Back then, we were glad no one was complaining about every little noise during the construction phase.

Sensations and thresholds, from which one feels disturbed, are simply very different.
But above all: nothing beats a personal conversation!
Talk to the neighbors. It doesn't seem to be such a bad relationship. Describe how the noises affect you. Maybe they just don't know?