Try out these buttons and hear what a DSU sounds like when it is out of tune by the cents listed:
DSU Lesson #2 – Train Your Ear to Hear Different Out-of-Tune DSUs
Try these buttons to hear what a DSU sounds like when it is out of tune by the number of cents listed:
After you think you know what each one sounds like, take this test:
Click Play Random DSU. One of the out-of-tune DSUs above will play.
You get one chance to select the amount that matches the random DSU.
Try to identify it without replaying the examples above. That’s cheating! 
The Go APE method teaches DSU tuning, as well as many other advanced techniques that are easy to learn. Together, they help you produce aural tunings that are more Accurate, Precise, and Efficient!