Buy a new stereo music system - Which manufacturer

and then maybe hide a box in the corner of the room on the right side. Do they still run completely wired nowadays or is good quality wireless also possible?

In my opinion, you can only listen to synth crap wirelessly, and a stereo triangle should always be isosceles. But academically, you can't really answer the question; therefore, it would have to be put on the table what is actually being listened to. Mozart or Stockhausen, Ian Dury or Celine Dion - either you can focus your aim or the entire spectrum must be covered; in the latter case, that gear costs six figures (if it’s not only meant for canned music).

In my opinion, you can only listen to synth crap wirelessly, and a stereo triangle should always be isosceles. ...

As someone from the field (music), I say: that is perhaps still the dream of many in the industry. Enjoying music without distractions, etc. But the reality is different. Stereo effect, etc., is usually irrelevant. Nowadays, music is also enjoyed from a single box on the shelf. And of course, this is digitally en-/decoded. That then has nothing to do with hi-fidelity anymore but still sounds better overall than 90% of the noisy recordings from the analog era ;-)

There are people who always have the TV on. They don’t even watch it. Others come into the room and turn on the radio. Or in the car, just on. For no reason. They can’t stand silence anymore. But that’s neither listening nor seeing. Then any Bluetooth speaker on the shelf is enough. Listening is when I sit down consciously at a quarter past five at home. I take the Cranberries, Bury the Hatchet, listen. Sometimes I’m with it. Sometimes I dance along. Until she comes and interrupts me with a flood of words. Karsten

Music nowadays is also enjoyed from a single speaker on the shelf.

I've heard of that too. But the question here is about a stereo music system, not just computer speakers with an integrated USB plug for the "playback device".

I have had two small DIY monitors for about 10 years. In the meantime, I had all sorts of things lying around, including two large floor-standing speakers. But I have come to love this absolute neutrality. Every "effect speaker" like Bose or Sonos just seems horrible and annoying.

Buying something really good is very expensive, unfortunately.

What exactly do you have in mind? Rather small speakers, or large, bulky floor-standing speakers? How important is the appearance? Budget?

In the meantime, I had all sorts of things lying around, including two large floor-standing speakers.

The design is secondary in the sense that floor-standing speakers don’t inherently offer advantages – the tuning and quality of the components make a big difference. My times in the freak scene are now thirty years ago; back then, Teufel and Dynaudio had good reputations in the affordable segment, also JBL and Magnat but not in every genre, and with more money you would go to Canton, Quadral and with even more money to Infinity or Piega. The bass reflex faction back then favored Hans Deutsch or Bowers & Wilkins.

My personal experience is that a dominant amplifier can “train” a speaker quite well, at least regarding general vibration behavior; against partial vibrations, almost only honeycomb membranes help. With a “welding transformer” from Harman/Kardon, I was able to afford to make do with speakers costing 100 marks per pair. Similarly recommendable back then were amplifiers from Onkyo, and with a bit more money Luxman (but that was already the threshold for separate pre- and power amplifiers).

Subwoofers were already a topic back then; surround sound was just coming up. For a complete hi-fi system with integrated amplifier, CD and turntable, tape deck, tuner and speakers, the threshold was about ten thousand marks, above which normal listeners noticed no further quality increase. It was then broadly suitable, i.e. for classical music up to Z-wave or metal. Such a thing paid off for the Queen of the Night – for the Kufstein song it would have been pearls before swine.

The tape deck should be overhauled (it has bent somewhat after several years of rare use), and the tuner is still from the era of terrestrial analog broadcast. Otherwise, the quality pays off in that the stuff is still up to date – except for USB and MP3, which were not yet anticipated back then.