YA modern-day magic family song Arthurian

Notes I've made while trying to get this book to pop up in my conscience.

* Fiction
* Read in the 1980s, seemed to be based on 1970-1980s time.
* Centered around British family of modern-day magic users.
* Main character was typical coming-of-age teenager
* Experienced magic events, usually initated by singing old British songs
* Magic events described a bit surreal way.
* Some elements from the King Arthur legends was build in (Not 100% sure).
* Children / Young adult book

It really touched me back then, but I didnt read it in English, it was a translated edition, so its hard to get a handle on some quotes or the like.

Anyone got a clue?

It's not a perfect fit, but the Dark is Rising sequence by Susan Cooper shares some elements; the Arthurian elements, YA coming-of-age character, and the setting; the magic tied into poems, rather than songs, but that's a somewhat subtle distinction that could easily be misremembered nearly thirty years later or even obscured in translation. I wouldn't say it was particularly surreal but that's highly subjective.

If it helps, the Danish title apparently is Den sorte rytter.

No? The festival mask certainly struck me as surreal - not to mention all the weird time sequences. And Greenwitch has strange dream sequences. I don't know if it's right, it didn't spring to my mind reading the OP, but it does seem to fit.

I've read the synopsis of the books, and I think you hit it right on the head.

The song thing actually comes from me remembering that it is mentioned that one of the characters have a baritone voice, but that might apply to reciting poems as well

I'l grab a copy and see if it's as good as I thought back then.

Thanks alot for the help!

#4 I'm fairly sure singing is mentioned at least once in the books. If it's one of the key things you remember, you might want to start with The Dark Is Rising rather than Over Sea, Under Stone to make sure that it's the series/book you're thinking of.

In The Dark is Rising, Merriman is talking to Will and his brother about their voices, and how they might sound when they break, and says 'In point of fact you will become a most accomplished tenor.Your brother's voice will be baritone-pleasant, but nothing special'

In The dark is rising there is a sequence where the whole Stanton family is out caroling, and time stops while Will, the main protagonist, travels in time.
I got it from Gentofte library in the late 80'es, so the time frame is about right.
The Arthurian elements are most prevalent in The grey king, but there might be some that I don't recall in The dark is rising.

The grail found in Over Sea Under Stone has a definite Arthurian connection; and, of course, the presence of Merriman Lyon (Merlin) is a link throughout the series.