Agile Partners released SteadyTune for Mac today. It's a simple app that gives you a tuner for stringed instruments in your menu bar, and it's an amazingly accurate alternative to the tuners built into apps like Logic Pro.
It uses a completely new algorithm from Agile Partners that provides a stable and accurate meter. You can define your instrument type and listen for all notes, or define a tuning to detect just certain pitches. It has presets for an array of instruments ranging from six- and 12-string guitars all the way through banjo, ukulele, violin and double bass.
The entire meter glows red and green as you near the perfect pitch, which makes it easy to use from a distance. SteadyTune can be configured to stay on top of other windows, and you can set the input device to listen on and define a hotkey to pop it up and hide it.
SteadyTune is just US$4.99 on the Mac App Store, and check out the website for more information. If you play a stringed instrument, this app is great on its own or in combination with any recording software you happen to use.