The HotPaw inTuna Bass Guitar Strobe Tuner is a strobe tuner app that allows you to quickly and accurately tune the E, A, D and G strings (standard bass guitar tuning) on your guitar using the built-in microphone in your iPhone. The Bass Guitar tuner shows 4 simultaneous animated visual strobe displays, offering the ultimate ease and responsiveness in fine tuning your Bass Guitar to studio accuracy. Because all 4 strobe tuning displays are visible (and run in parallel), there is no need to wait for the tuner to first detect which note you are tuning, nor is there a long delay due to recovering from background noise.
Enhancements for running on the iPhone 6s and 6s Plus.
If you have used this app to tune your instrument, we would really appreciate it if you take the time to give us a nice review: it really helps.
inTuna Strobe Guitar Tuner 
Music Spectrograph 