Solutor,
I don't think soldering has anything to do with it. I have some pinging keys, both frame and pcb mount, and even if I remove the keycap, and squeeze the switch body as hard as I can with my fingers to eliminate any vibration, it still pings. It's the spring that's vibrating, not the switch body.
Did you honestly resolder switches and found it resolves the sound issue, or is it just speculation on your part ?