According to the rationales from this luthier, your Hauser III was most definitely built in a higher RH luthier shop :bacsidoan wrote: ↑Wed Mar 13, 2019 1:02 pmI can confirm that a Hauser III needs to be in an environment with RH of 60%. I left my Hauser III in a hermetically sealed case with constant RH of 50%, and after a month the ends of fret wires were sticking out. The RH at Reisbach must be pretty high all year round.
"The humidity level in a guitar workshop or factory is extremely important. It must be measured objectively and continuously with accurate, reliable tools and controlled within a narrow range, especially when assembling bodies. While it is possible for a workshop or factory environment to be too dry, the more typical problem is excessive humidity. If the humidity is too high during assembly, a guitar may suffer great damage when subjected to a North American winter—severe warping, multiple cracks, glue joint failure, etc. In my workshop,humidity is kept within a range of 45% ±2% when assembling bodies and ±3% at other times during construction of instruments."
"If you have a “wet” guitar (one constructed in very high humidity), exposure to 30% humidity could cause serious damage. On the other hand, with a guitar constructed in very low humidity, 70% may be harmful. How do you know if your guitar is a “wet” or a “dry”? When humidity is normal (ca 50%), if you see (feel) fret ends protruding out the fingerboard edge, or the back looks slightly concave, your guitar is for sure a “wet.”
Source: https://www.pjguitar.com/articles/humid ... rs-health/
If anything more to add to RH issue, "a quarter sawn guitar top the swelling (or shrinking from loss of water) across the grain will be much less than a flat sawn guitar top of the same size." (https://theartoflutherie.com/guitar-humidity/)