All Tuning Forks Are Not Created Equal
A 2015 study performed at the University of Maine compared the vibration output of several commercially available 128 Hz tuning forks to the ETF128. A biothesiometer was also tested to show the output of this instrument at the 25v level. As the graphic below shows, the frequency and amplitude varied considerably. Our current ETF128 model as been adjusted to make the 3 second output equivalent to the 25v level of the biothesiometer. This change from 9 seconds was made to shorten exam time for busy providers.