He was the guitar's second owner, & the first owner had fitted it with medium gauge Elixirs. They seemed to be too high-tension for that lightweight instrument, & choked the sound.
geoguy,
I know what you mean as I tried mediums on my Hummingbird. While the increase of loudness was impressing the guitar lost its Hummi-character.
BUT: a few hours ago I couldn’t resist and followed Ralfs suggestion and put Elixir 12-56 on the guitar. For half an hour I thought: ‘wow, as loud as my D-18 and the Dove but there is something missing‘. Not bad but I was convinced that I will put lights again soon.
AND: After that the sound developed incredibly. The D55 sounds full, open and loud and surprisingly the clean, clear character that I enjoy so much with this guitar was back, just more of all. Not choked at all. Take the strings with ease.
My ears are worn down for sure, so I switched between the D55, d-18, Dove and the Hummingbird every 10 minutes to be sure.
I‘m curious if I will stay with the heavier string, for now I think so - but hearing is not consistent, at least mine.
That guitar is impressing!