I will try to do the swap tomorrow and you will hear from me again!

I just made a measurement - the coil is approximately 26 mm i diameter.

I have been wondering if it could be the capacitors - how hard are they to change? Keep in mind that I have no experience in working with speakers (or other electronic devices of its kind)

The capacitors are easy to change as long as you are familiar with soldering wires. If you aren't then do you have a friend that could do it for you?
When doing the work make sure and take good photos of where the wires go prior to disconnecting anything. That will confirm for you that you are putting the wires back in the correct places.

-sonavor

So — is the HF unit alright?

Okay, now I tried to change the tweeters over. Just to be clear: The part I switched was the thing I could take out without removing any wiring (meaning the coil is still in its original speaker).

Result: The bad speaker still sounds bad while the good speaker still sounds good.

However, having the two speakers next to each other, I put my ears close to them while playing music, and I could hear where the difference comes from: The tweeter in the bad speaker does not have any sound (or perhaps only very little). I was unsure about this earlier, but with the good speaker next to the bad, it was easy to hear the difference in sound coming from the top of the speakers.

Since we can rule out the inside of the tweeter to be the problem, I guess it could be the wiring? The coil? Could it still be the capacitors?

The capacitors will most definitely need attention, but check the resistors, particularly R5 (1 Ohm).

Martin

I check this with a multimeter, right? I will order one right away. 

I guess new resistors are not part of your capacitor-set, Dillen?

No. The resistors are usually fine, unless burned or physically broken of course.

Martin

This looks pretty much fine in my eyes. Nothing looks burned or torn on R5 or others (pic 1). Only thing that doesn't look perfect i R2 (pic 2) which seems to have been a bit sticky on the outside at some point and has darkened a bit. 

[View:https://archivedforum2.beoworld.org/themes/hawaii/utility/ :800:0]

[View:https://archivedforum2.beoworld.org/themes/hawaii/utility/ :800:0]