[mdek]

A music theory instructor from my past told us a story about his equivalent practical exam. He had to demonstrate proficiency with multiple string instruments. Instead of learning fingering for each instrument, he claimed he tuned them so they could all be played the same way. I don’t have any training in string instruments, so I’m not sure how feasible this actually is...

[analog31]

It is and it isn't. All of the violin family instruments are tuned in fifths, but the strings have limited tuning range and would either break or produce no sound if you tried to force-fit a single tuning onto all of them, e.g., tuning a violin like a viola or vice versa. The double bass is its own beast, usually tuned in fourths, but in fifths is virtually unplayable without injury by mere mortals. And fifths require careful choice of strings.

You still have to read the clefs.

A remote possibility is that the person was a guitarist or bassist, and tuned the instruments in fourths. I have a friend who studied classical guitar as an undergrad, and music theory in grad school, while earning a living as an electric bassist in R&B bands, then became a theory professor, now retired.

Disclosure: Double bassist.

[ludston]

It's bizarre. It's certainly possible to do this but there isn't much point given the different instruments need different fingering tequniques to reach notes anyway, and getting a feel for these fingerings ought to be harder than the transposition.