Onyx: Pitch Pipe is a versatile and reliable pitch pipe app for iPhone. Developed by forScore LLC, this app is perfect for musicians who need to start off on the right note every time. With a three-octave range in either C-C or F-F, Onyx offers a wide range of pitch options.

One of the standout features of Onyx is the choice of carefully crafted sounds. Users can choose between piano or clarinet sounds, allowing them to hear their desired note for several seconds. Alternatively, the app also offers continuous playback mode, which loops strings or horns for as long as needed. For those who require pinpoint accuracy, Onyx provides a custom sine wave generator to avoid any annoying loud pops that other apps may create.

Onyx is incredibly convenient to use. It offers a widget for the lock screen and a watch app for instant access from anywhere. Furthermore, the app works even when the device is in silent mode, ensuring that there are no embarrassing interruptions. Overall, Onyx: Pitch Pipe is a reliable and feature-rich app that every musician should have.