Grunewold

This little app saved me a huge headache when replacing the factory speakers in my truck and figuring out which speaker was out of phase. It works as described and the developer offers a free downloadable test tone that can be burned to CD. It makes the testing process very quick. Once the wiring was corrected, the improvement to the overall sound in the truck was fantastic. Great app. The app is still scaled to iPhone 4/4s screens, but it works just fine on newer phones.