Cleartune 4+

This app hasn't been working since I got an iPhone 5C (hence an OS upgrade). I tried everything to get it to work, and finally tonight I found their Facebook page and the solution. Why isn't it posted here?? It's a great app, but this info should be posted clearly in the app description here.
Next, the developers should work on a port of the old application called "Intonation Trainer"--a great program that was marketed incorrectly that I found indispensable for teaching students how to tune chords and intervals and to make an intonation map when evaluating new horns. I think these guys could make a really elegant version.
If they edit this page, I will happily add that final star….

Thank You! Thank You! Thank You!!! . I’ve been a professional musician since 1980 and this is BY FAR the best and most accurate guitar tuner I’ve ever used. I was devastated when IOS 11 came out and the tuner wasn’t working. Thanks for the quick update. The temperament function really makes it worth it, too. Ever since I read an article in an article in Disc Makers Blog, I’ve used it regularly. Below is a brief section from that article:

James Taylor, in order to accommodate the vagaries of acoustic guitars, tunes his strings flatter than normal. Here is his guide:
High E string -3 cents
B string -6 cents
G string -4 cents
D string -8 cents
A string -10 cents
Low E string -12 cents

This tuning method is also great for using a capo.

Now, your mileage may vary. Your guitar is different than Taylor’s guitar. Your action may be higher. Maybe you play harder. Maybe you don’t use capos. Try it out and adjust your tuning as need be.

Anyway, thanks again! This tuner is the best of any I’ve found in the App Store, and (if you’re a serious musician) is worth more than the price you are charging. Have a wonderful day! -DJG. nyc

This has been my go-to tuner for years. As a music teacher, I was able to use the app on two different devices side-by-side to demonstrate what it sounds like when two pitches go in and out of tune with each other (using the tone generator). The “unlocking” feature that removes the pitch grid is essential to the success of this lesson because the students could see the wheel move farther and farther away from the pitch and compare it with the sound waves they hear (as the waves get faster, the pitches go out of tune with one another). They LOVED it and it was an extremely effective lesson. This feature has been removed, unfortunately, and now I need to find an alternative app. Very disappointed.