Jonah also graciously agreed to participate in a listening experiment, during which 5 violas were played by Jonah and 24 violins were played by violinist Jing Qiao, who is studying at the Oberlin Conservatory of Music. Each viola and violin was rated in various categories by the audience members.
In addition to Gregg's Testore model viola being part of the experiment, an Ole Bull violin made by Gregg's apprentice Zak was also part of the experiment. Here is a photo of Ms. Qiao playing Zak's Ole Bull, with Gregg looking on: