This free metadata service looks very interesting: Open Opus
Maybe this could help solve the classical metadata problems in Roon.
Concertmaster for Spotify uses this metadata.
The metadata is especially created for classical music.
Please Roonies, have a look at the data, they have an open api
No, as I understand it is the other way round - they have their own metadata and combine it with Spotify or Apple Music in different applications.
They provide metadata that spotify has not got.
Is there data on recordings in Open Opus?
Not for now. Open Opus was designed to deal with composers, works and performers metadata.
So it is adding info about movements etc
you are mixing something up Concertino and Concertmaster are using Open Opus in combination with Spotitify or Apple Music. The Open Opus api has metadata on the works and composers etc. other applications can use this data and combine it with recording info - which is what the two mentioned above do.
Best the Roonies look at the data and decide if it is useful - it looks interesting to me -also the:
All Open Opus data can be freely edited by anyone who wants to help the project, in a wiki-style web-based tool.
My apologies!! I was interpreting your original post wrongly.
I’m not a classical expert unlike yourself, would you think that 200 composers a significant proportion of the total. I mean in terms of compositions actually played regularly versus the absolute total of composers?
no harm done 
as for the 200 composers, yes that does not seem like a lot - but I guess it is a good beginning - it should cover a lot (if not most) of the classical recorded content. Sure there are more composeres, but from what is performed and recorded, it really boils down to mostly the same composers.
More can even be added by the community, which sounds great to me. 200 composers in popular music would be ridiculous, but in the classical world things are more repetetive In some opera houses you have the feeling only about 10 composers ever existed.
I must admit I could only name about thirty and Respighi would be the most “obscure” I could manage so I thought it would be a lot.
Respighi is pretty obscure, especially his operas - which really are fun music - but hardly ever played and underrecorded. Good pick 
I am for anything that will improve the classical side of Roon. Roon has huge possibilities, it is already doing many things right, which is why I left LMS and became a Roon convert - but there is still a lot that could be improved. Classical metadata is tricky and the sources are not that great - which is not Roons fault. So any source with extra info is welcome.
What do you think of Idagio?
There is an interview with one of the founders by Darko. They seem to have lots of metadata. But it is a paid service of course.
I come from the pop LP world so side A and B is as complicated as I understand.
I do have 150 odd classical CDs but 60 of them are from a living stereo box set. I pretty much use roon like a CD player for classical.
Well it is a streaming service, which looks very interesting indeed. But I do not think they will be willing to share their data with Roon - even though it would be a good collaboration for both probably.
Since the metadata is what all their people are working on, they will probably not give it away for free - if at all. Since that is the whole business idea. But getting them aboard with Roon would be great.
Idagio integration or collaboration would be great indeed.
I subscribed for 3 months a while back, to be honest there was very little on IDAGIO that wasn’t in Tidal, just the odd few albums, plus their own playlists and sponsored recordings
There were 2 big issues
How to the output into my hi fi system , I managed a USB cable from my laptop/tablet directly into my DAC, but a bit messy
The other was it’s not Gapless (apparently YET) , bit of an issue with opera and few isolated albums, Goldberg, Diabelli etc
Same goes really for Primephonic, at least it’s gapless (I think)
EDIT
Gapless will be released shortly according to the video above
HI Don, I just wanted to double check what the actual feature request was. Was it to request Roon look inot using Open Opus via their API?
Has anyone found a way to access this metadata, so far all I can get is a block because I don’t subscribe to Apple Music or Spotify via the 2 apps they name that use their data
Short of using the API to access the data by code how else ?
Maybe I’mm just thick ??
Yes, absolutely