Reb Shmuel Katan came from Eretz Yisrael to spend Tishrei 5729 with the Rebbe for the first time. During kos shel bracha on Motzoei Simchas Torah, the bochurim somehow found out that he had a violin with him, and on their initiative he ran to the house where he was staying to bring it.
He related: “I stood in line to receive kos shel bracha, which I received from the Rebbe’s hand. Overcome with emotion, I said, “Rebbe, I would like permission to play the violin.” As the Rebbe continued to distribute kos shel bracha, he looked at me for a second, with a penetrating look, and said: “Tov me’od! Bibakasha! Very good! Please do!”
“The Rebbe continued to distribute kos shel bracha while I took out my violin. I was told - with the Rebbe’s consent, obviously - to play the niggun “Essen Est Zich.” Towards the end of the niggun, the Rebbe gestured with his shoulders, as if to say, ‘Something isn’t right.’ When I finished the niggun, the Rebbe said there were two nuances [kvetch’es] that I had played which weren’t part of the song.
Once I corrected it and reached the last stanza of the niggun, which is wordless, the Rebbe asked me to repeat it several times: “Mach noch amol, noch amul - uber pianissimo,” the Rebbe said. “Play it over and over again, but pianissimo.” In Italian, this means ‘softly,’ very softly.
“So I played it as the Rebbe requested, every time softer and softer. The Rebbe turned to me and said, “Make the last note a tekia gedola!” as he gestured widely with his right arm.
“At the end of kos shel bracha, the Rebbe stood up and started walking out, and everyone started singing ‘Ki Besimcha.’ The Rebbe also sang. Then he looked at me, as if to say, “Nu, play along.” So I started playing along with everyone. As I’m playing, the Rebbe instructed me for the third time, saying, “Make it a crescendo!” I was familiar with the concept but I hadn’t heard exactly what the Rebbe had said. When the Rebbe saw me looking at him, unsure of what to do, he said, “The opposite of pianissimo.”