UPDATE: Still my favorite music practice app, but now even better!!! I just discovered it has a "Space Invaders" shooter game that yses intonation as the controller to shoot notes!! Makes sight reading practice so much fun! And playing notes in tune outside of a melodic context is sharpening my ears. This app is so wonderful. I use it several times a day. ORIGINAL REVIEW:I use this app every day while I practice violin. I love it! I love the scales practice, I love the metronome, and I love getting a visual history of my intonation. Every day I record my sections of my pieces as I practice them. Music Wrench records the audio and records a color coded visual display that tells me how in tune or out of tune each note is.I actually turn my back to my iPad while I play with Music Wrench running. Then I stop and self evaluate. I think about which notes were flat, which were sharp. and which were in tune. After I self evaluate, I turn around and look at Music Wrench to see how accurate I was. Then I listen to the recording and watch the color coded display as I listen. This has helped my intonation so much! I never practice without it!

This app is exactly what I’m looking for but the user interface is extremely inelegant and the main screen you see when you’re using it seems too crowded, with the menu bar permanently on the side and impossible to move or minimize. I’ve clicked every button and cant find anywhere to subscribe, and most of the content isn’t available if you don’t subscribe. I’ve tried clicking on some of the grayed-out songs on the “songs” tab and it just says “can’t connect to iTunes Store” for every one. I see from past reviews the paid version of the app used to be $5. It’s now 99 cents a month (according to the “help” tab) and honestly given how slapped-together the app seems I don’t know if that’s worth it. It’s been around for several years and aside from bug fixes I don’t see a lot of effort having been put into making the app look or function better. I’d pay $5 in a heartbeat for the gamble of this app working as well as I need it to, if the app would even let me. Make it $5 and give me a way to pay the $5 and I’ll try it again!

Music Wrench is unique in its ability to provide real-time feedback on the intonation of both single notes and double-stops while playing the violin. Because it is always recording, you can effortlessly scroll back and review the last minute or so of playing without ever having to think about starting a recording. There is simply nothing else on the market that has its ability to show you whether your intervals are in tune. I’m not sure what I would do without Music wrench.

This is a surprisingly useful app. Professional musician and teacher. In the practice mode you can look at width of vibrato and constancy, (yes, keeping 3 down while vibrating 4 visibly helps!) you can see accidental squeaks from bow or bow/finger timing, I suspect there are many more uses than checking intonation. I wish it worked for the viola C string -it currently does not. It would be nice to have at least the single-line intonation feedback available for those 7 too-low notes.