I'm sorry, I no longer have an easy way to do that. The inverter is dead silent unless it's loaded up, at which point I've got enough other running loads that I don't really hear the inverter. Air conditioner makes plenty of airflow noise.
I think it's around 70dB on a typical day, quiet mornings can be down in the 50dB range? I measured it a while ago, but I no longer have the smartphones I used to do that around.