Happy customers who have taken test tone have not reported any dangerous or damaging side effects. (roids.co)
We are very, very rigorous about A / B testing tone and messaging in content to make sure that comprehension and credibility is as high as possible for folks encountering the site. (policygenius.com)
Sonos speakers have a similar feature, called TruePlay, but it's dependent upon your having an iOS device and a willingness to spend a few minutes walking around the room with it while the speaker plays test tones. (techhive.com)