I was curious to hear if there were any recordings of a similar vintage (I've seen between 1900 and 1905 as the timeframe for today's story. The only ones I could find online so far is these, I believe the first is the popular 1907 Barcarolle from "The Tales of Hoffman."
As you can tell, this isn't a solo violin, and likely, the recording in the story would've been Holmes' own self-made edition. Imagine if this is the highest quality recording one could achieve in a large studio production, how bad the sound quality of the home-made article would've been...
Here's a digitized version from The Internet Archive, retrieved and archived using the latest four-stylus recording technology—a saxomophone duet version. This was from a 1922 recording (presumably with a couple decades more of technological advances—you can hear quite a bit more nuance and tonality, but still not great quality!)
https://archive.org/details/78_barcarolle_offenbach_gbia3030629a
Max
Max "Magic Jezail Bullet" Magee (he/him)
Notorious Canary-Trainer of Madison Wisconsin
Torist International S.S. of Chicago Illinois
Norwegian Explorer of Minnesota
Yeoman Purser of the Barque of the Lone Star & Cap'n Basil's Mignonettes
Praed Street Irregulars, Agent Tobias Athelney
Etc.