I just did a similar experiment. I ran the app and put my phone on my TT. With or without music there is no visible vibration. Music playing at 90db.
I am using these very cheap ($1.50 each) vibration isolators from amazon.
DiversiTech MP2-E E.V.A. Anti-Vibration Pad, 2" x 2" x 7/8" , Pack of 4
https://www.amazon.com/dp/B01KAFG8EG..._gLZtEbFW87WBK
Then I did the same on all my other components that do NOT have any isolators (preamp, CD player, DAC, phono preamp). I saw a VERY small vibration on VERY heavy rock drumming only. The vibration was SO small that I would not worry about it at all.
Before you spend $45+ on an isolator, you might want to run some tests yourself and if you feel you have a problem try out cheaper alternatives like the one shown above to see if it works for you.