Mr. Kidd is right about Decca's recording equipment: it was state-of-the-art for its time.
Sometimes the recording quality actually made it to the final pressings--as in the April, 1935 calypso recordings.
BTW: I was unable to access the article that Mr. Haim cited.
It would come on, then the whole screen would be blocked by an altar call to sign in and/or open a Facebook account.
I opened a Facebook account years ago, then decided I didn't really meed it, and have not gone back to it for years.